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Gomar
2012-Nov-13, 02:11 AM
expert says aliens dont exist

http://www.thesun.co.uk/sol/homepage/features/4631083/UFO-expert-Dr-David-Clarke-asks-whether-its-time-to-admit-aliens-dont-exist.html

ifcourse the white man did not exist until he landed in the New World and Australia.

tnjrp
2012-Nov-13, 07:57 AM
Robert Sheaffer was less than convinced about the expertise of the previous "UFO expert" who said basically the same thing, as can be found out in this thread:
http://cosmoquest.org/forum/showthread.php/139270-They-want-to-believe-but-it-s-just-so-very-hard

Clarke would seem to have a little stronger legs to stand on tho. Just because of that, here's his original text that got quoted in The Sun:
http://drdavidclarke.co.uk/2012/11/04/ufology-dead-again/


Most seasoned observers will agree the numbers of significant and evidential UFO events have declined in the past decade as the debate has become increasingly focussed upon the twin myths of “saucer crashes” and alien abductions. As the obsession with abductions has died away, we have seen the resurrection of tired old sacred cows such as Roswell and the new Roswell (Rendlesham), both endlessly revived and re-revived for new audiences

Jens
2012-Nov-13, 08:19 AM
expert says aliens don't exist


I think the title is deceptive, or wrong. The person isn't saying he doesn't believe aliens exist, but rather that he doesn't believe that aliens are visiting the earth. Whether they exist or not is a completely different question. Personally, I think it is quite likely they exist, but very very unlikely that they have ever visited us.

ravens_cry
2012-Nov-13, 08:36 AM
Oh, yes, that is indeed a very, very different scenario. Given the distances involved, the rather fundamental laws that Nature seems to insist on for how fast we can even go theoretically, and the energies required to even attain those speeds, I would say that, while it is possible Earth could have visited sometime in its history, perhaps even when there has been life, the chance seems minimal and the evidence rather lacking.

primummobile
2012-Nov-13, 12:31 PM
I think that if aliens had visited us, particularly at any time in the last century, they would have made their presence known and attempted to communicate. I think that things like the so-called "Prime Directive" are overly idealistic and a little silly. If there is any other intelligence out there then they evolved from the same "stuff" from which we evolved.

Solfe
2012-Nov-13, 12:53 PM
I think that if aliens had visited us, particularly at any time in the last century, they would have made their presence known and attempted to communicate. I think that things like the so-called "Prime Directive" are overly idealistic and a little silly. If there is any other intelligence out there then they evolved from the same "stuff" from which we evolved.

In these UFO scenarios, why don't the aliens ever want "Tribal Artwork" or land for development? They seems to make it to the point of stealing women or water, but strangely never both at the same time. :)

tnjrp
2012-Nov-14, 06:07 AM
Among the most compelling reasons I've heard for aliens to come visit us would indeed be our "tribal artwork". The higher the emergence layer, the more divergent we probably are from the hypothetical visitors and given that culture is piled on top of biology piled on top of chemistry piled on top of physics it's our best chance to offering them something they haven't though of themselves yet. Forget about them landing on the White House lawn, they'll head straight for the ticket queue of the next big Lady Gaga concert.

ravens_cry
2012-Nov-14, 08:15 AM
'Tribal art' is possibly the only thing we would *have* of value beyond our solar system's raw materials. After all, the laws of physics are the same everywhere, so certain technologies might crop up repeatedly, and even if ours are unique they may not be any better.

primummobile
2012-Nov-14, 12:27 PM
...they'll head straight for the ticket queue of the next big Lady Gaga concert.

I wouldn't be too sure of that. They might think that Lady Gaga is one of them.

Solfe
2012-Nov-14, 08:05 PM
I wouldn't be too sure of that. They might think that Lady Gaga is one of them.

As I saw on one of the internets "Holy Cow, Batman! Lady Gaga has kidnapped The Commissioner again."

eburacum45
2012-Nov-14, 10:04 PM
Dr David Clarke is one of the most level-headed experts on the UFO phenomenon it is possible to find.

Nowhere in that essay does he say aliens don't exist; that comes from the headline-writers at the Sun, who are probably the most appalling headline writers it is possible to find.

tnjrp
2012-Nov-15, 07:13 AM
The aliens might be tempted to come and read those headlines. "Teh w0rst in teh Universez, man!"

Colin Robinson
2012-Nov-15, 08:05 AM
I think the title is deceptive, or wrong. The person isn't saying he doesn't believe aliens exist, but rather that he doesn't believe that aliens are visiting the earth. Whether they exist or not is a completely different question. Personally, I think it is quite likely they exist, but very very unlikely that they have ever visited us.

I agree that the headline goes way beyond the content. Whether "aliens" exist, and whether they have visited Earth are indeed quite different questions. For that matter, whether they've ever visited Earth is a different question from whether they've been visiting Earth in the past few years, in craft that get seen and reported as UFOs…

The argument about camera phones is only relevant to the last of these three questions, surely?

R.A.F.
2012-Nov-15, 03:02 PM
... whether they've ever visited Earth is a different question from whether they've been visiting Earth in the past few years...

Well, it may be a "different" question, but the answer is the same for both...ie. there is no credible evidence that the Earth has EVER been visited by ET's.

primummobile
2012-Nov-15, 03:04 PM
As I saw on one of the internets "Holy Cow, Batman! Lady Gaga has kidnapped The Commissioner again."

Just proves that you can't trust E.T.

Paul Wally
2012-Nov-15, 08:24 PM
Well, it may be a "different" question, but the answer is the same for both...ie. there is no credible evidence that the Earth has EVER been visited by ET's.

Even if aliens did ever visit the Earth, there wouldn't necessarily be any evidence of that.

KaiYeves
2012-Nov-15, 08:59 PM
I wouldn't be too sure of that. They might think that Lady Gaga is one of them.

I believe this parody music video (http://www.youtube.com/watch?v=h47fNaOb-JU) is relevant...

ravens_cry
2012-Nov-15, 09:35 PM
Just proves that you can't trust E.T.
Would you trust someone who looked like a shrivelled up hot dog?
E.T. I mean.:p

R.A.F.
2012-Nov-15, 10:02 PM
Even if aliens did ever visit the Earth, there wouldn't necessarily be any evidence of that.

Since there is no evidence, the default answer MUST be no alien visitors.


...or do you disagree?

Paul Wally
2012-Nov-15, 10:09 PM
Since there is no evidence, the default answer MUST be no alien visitors.


...or do you disagree?

I thought the default answer was we don't know.

Selfsim
2012-Nov-15, 10:43 PM
Even if aliens did ever visit the Earth, there wouldn't necessarily be any evidence of that.

I thought the default answer was we don't know.There's no credible evidence that aliens exist elsewhere, as well.

R.A.F.
2012-Nov-15, 11:01 PM
I thought the default answer was we don't know.


That makes the assumption that the 2 ideas, (that aliens have visited, or that aliens have not visited), are somehow equally likely...they are not.

Paul Wally
2012-Nov-16, 12:37 AM
There's no credible evidence that aliens exist elsewhere, as well.

Correct, but it's usually the inferences drawn from lack of evidence that tend to become problematic, e.g. the fallacy that absence of evidence is evidence of absence.


That makes the assumption that the 2 ideas, (that aliens have visited, or that aliens have not visited), are somehow equally likely...they are not.

I agree that they are not equally likely, but I reject your notion that not knowing somehow implies taking the '2 ideas' as equally likely.

R.A.F.
2012-Nov-16, 12:46 AM
...I reject your notion...

That's fine as I'm not trying to convince you of anything...just stating the obvious.

Colin Robinson
2012-Nov-16, 07:44 AM
Correct, but it's usually the inferences drawn from lack of evidence that tend to become problematic, e.g. the fallacy that absence of evidence is evidence of absence.

Well said.

There may be occasions when absence of evidence is evidence of absence. It depends what sort of evidence would be expected, if critters of a particular sort were in a particular place at a particular time. For instance, absence of spider-webs in a basement is quite good evidence of current absence of web-building spiders. But it doesn't prove there was never a spider in the basement.

The argument in the article cited by the OP, is that if, in an age of camera-phones and the internet, the Earth was being visited by extraterrestrial space craft, enthusiastic amateur photographers would take pictures of the craft and circulate the pictures online. In which case, absence of convincing online photos of ET spacecraft is good evidence that there are none here now.

But does this argument say anything about whether Earth has ever been visited by living things from other worlds? Surely not. Supposing a scientific mission from another star dropped in for a visit one billion years, or one million years ago, or even one thousand years ago, it would hardly have been photographed by a camera-phone!

Jens
2012-Nov-16, 07:58 AM
But does this argument say anything about whether Earth has ever been visited by living things from other worlds? Surely not.

I can hardly see anybody disagreeing with that.

Selfsim
2012-Nov-16, 08:47 AM
Correct, but it's usually the inferences drawn from lack of evidence that tend to become problematic, e.g. the fallacy that absence of evidence is evidence of absence.Nah ... the real problem is when folks succumb to the temptation of incessantly dwelling on speculative discussions, which then conjure up inferences about the 'likelihood' or 'prevalence' of exo-life throughout the obs. universe. (Which then, for some strange, inexplicable reason, seems to then reduce to 'rareness' of certain lifeforms, or rareness of remotely detectable 'bio-signs'... ie: the Fermi paradox, and the ensuing counter 'explanations' for the apparent lack of remnants, or present evidence).

That there's such a huge yawning gap in evidence needed in support of speculative exo-life 'rareness' explanations, by necessity, calls for the admission of the logical fallacy you mention. (If it weren't admissable, then your default answer of: 'we don't know', would be at odds with the imbalance created by the rejection of the fallacy).
So which of these 'evils' is it to be?

The inconsistency of the speculative framework for discussion would seem to be the culprit(??)
One can only conclude that such speculation would probably not be scientific speculation but something different ... like sci-fi, where there is no real need for such framework.

Solfe
2012-Nov-16, 11:44 AM
Pttf. I will continue to paint. Proof of aliens or not, my "tribal artwork hobby" is enjoyable. :)

R.A.F.
2012-Nov-16, 02:58 PM
There may be occasions when absence of evidence is evidence of absence. It depends what sort of evidence would be expected, if critters of a particular sort were in a particular place at a particular time. For instance, absence of spider-webs in a basement is quite good evidence of current absence of web-building spiders. But it doesn't prove there was never a spider in the basement.

Irrelevant comparison...we don't have to assume the existance of spiders, we know they exist. The same can not be said for aliens, past or present.

Colin Robinson
2012-Nov-16, 08:04 PM
Irrelevant comparison...we don't have to assume the existance of spiders, we know they exist. The same can not be said for aliens, past or present.

That depends what you call an "alien".

If you mean a living thing from one world visiting another, then the Apollo astronauts who walked on the Moon were "aliens" while they were there.

We know that life exists in the universe. We know that space travel exists. We don't know how common either life is or space travel is.

Another thing we don't know, is whether interstellar space travel (with a payload of living organisms) has ever happened or ever will happen.

R.A.F.
2012-Nov-16, 08:16 PM
That depends what you call an "alien".


Really?....that's your non-answer...semantics???


Nice dodge...you completely ignored the irrelevance of your comparison.

Colin Robinson
2012-Nov-17, 05:18 AM
Really?....that's your non-answer...semantics???

Nice dodge...you completely ignored the irrelevance of your comparison.

Semantics is the study of what words mean...

Are you saying that the meaning of a word like "alien" is irrelevant to this thread?

Selfsim
2012-Nov-17, 05:33 AM
That depends what you call an "alien".

If you mean a living thing from one world visiting another, then the Apollo astronauts who walked on the Moon were "aliens" while they were there.
...
Semantics is the study of what words mean...

Are you saying that the meaning of a word like "alien" is irrelevant to this thread?C'mon Colin … you were using an Apollo astronaut as an example of an alien!!!

I think most here know the difference between semantics word-play (like: 'Apollo astronaut= alien') and an exo-lifeform 'alien'!??

RAF wasn't implying anything!

Colin Robinson
2012-Nov-17, 07:15 AM
C'mon Colin … you were using an Apollo astronaut as an example of an alien!!!

As an example of a life-form from one world visiting another world. Yes.


I think most here know the difference between semantics word-play (like: 'Apollo astronaut= alien') and an exo-lifeform 'alien'!??

Terms like "exo-lifeform", "ET", "extraterrestrial" are based on a conceptual division of the Earth from the rest of the universe — the pre-Copernican distinction between what is terrestrial and what is celestial.

Yesterday, Selfsim, you made the following statement...


There's no credible evidence that aliens exist elsewhere, as well.

It is true that we don't yet have conclusive evidence of life on worlds that we haven't yet explored at all thoroughly for life. And only a life-form from one of those unexplored worlds would count as "an exo-lifeform 'alien' ".

On the other hand, the only planet we have explored thoroughly for life, turns out to have living things all over it.

Generalizing from a sample size of one is not the best way to draw conclusions about life in the universe. But it has to be better than forgetting about the one and only case study we have.

Paul Beardsley
2012-Nov-17, 08:27 AM
I think it's actually quite easy to use suitably tentative language to cover all bases accurately:

Based on our substantial but far from complete knowledge and understanding of biological processes and planetary formation and development, it seems very likely that life has arisen elsewhere in the universe. However, given that we do not at this point have a full understanding of how non-living chemicals give rise to life, the claim that extraterrestrial life exists remains an extraordinary one.

Given our understanding of the scale of the universe, the difficulties of space travel, and the inability of people to keep secrets, it seems extremely unlikely that aliens are currently visiting Earth. There is no evidence that aliens visited Earth in the past; this does not rule out the possibility that it has happened at some point, but such a claim would be another extraordinary one.

I think I understand Colin's point. It may be true to say, "We don't know!" but our ignorance is much more educated than it was; saying "We don't know!" for decade after decade suggests we haven't learnt anything new. Unfortunately we find we have to still say it because people keep making extraordinary claims.

Colin Robinson
2012-Nov-17, 10:22 AM
I think it's actually quite easy to use suitably tentative language to cover all bases accurately:

I appreciate your effort to cover all bases, Paul.


Based on our substantial but far from complete knowledge and understanding of biological processes and planetary formation and development, it seems very likely that life has arisen elsewhere in the universe.

Yes!


However, given that we do not at this point have a full understanding of how non-living chemicals give rise to life, the claim that extraterrestrial life exists remains an extraordinary one.

Given our understanding of the scale of the universe, the difficulties of space travel, and the inability of people to keep secrets, it seems extremely unlikely that aliens are currently visiting Earth. There is no evidence that aliens visited Earth in the past; this does not rule out the possibility that it has happened at some point, but such a claim would be another extraordinary one.

I'd add that if Earth has ever been visited by creatures from another world, microbes from ancient Mars, riding space rocks, are more likely than beings in hi-tech space craft from another star system.


I think I understand Colin's point. It may be true to say, "We don't know!" but our ignorance is much more educated than it was; saying "We don't know!" for decade after decade suggests we haven't learnt anything new. Unfortunately we find we have to still say it because people keep making extraordinary claims.

What about the words in the title of this thread (from the headline of the article quoted) "aliens don't exist"? Do they also constitute an extraordinary claim?

I think they do, because (taken literally) they claim that Earth, as an abode of life, is unique in the universe.

Paul Beardsley
2012-Nov-17, 10:37 AM
What about the words in the title of this thread (from the headline of the article quoted) "aliens don't exist"? Do they also constitute an extraordinary claim?

I think they do, because (taken literally) they claim that Earth, as an abode of life, is unique in the universe.

Yes, of course. It is asserting a conclusion that is not supported by evidence. If anything it is worse than saying, say, "There is definitely life at Tau Ceti," because at least that statement could, in principle, be confirmed or disproven.

But the (perceived) readership of The Sun is not interested in considered statements of probability. It wants alien invaders or a scarily empty universe.

R.A.F.
2012-Nov-17, 04:25 PM
Are you saying that the meaning of a word like "alien" is irrelevant to this thread?

So you like playing word games, eh?


Are YOU saying that you can not rationally address my post regarding your irrelevant comparison of "known to exist" spiders, with "not known to exist" space aliens, without playing word games??


What?...you don't like it when someone "puts words" in your mouth??...well, guess what? neither do I.


Now if you would like to try again, and come up with a comparison that doesn't involve "things that we know exist", then be my guest.

Colin Robinson
2012-Nov-17, 06:00 PM
So you like playing word games, eh?

I like considering and discussing the meaning of the terms we use. Yes.


Are YOU saying that you can not rationally address my post regarding your irrelevant comparison of "known to exist" spiders, with "not known to exist" space aliens, without playing word games??

The word "space" in your term "space aliens" means what?

Is the surface of a planet a place in space? Or does "space" just mean the space between planets?

Or does "space" mean anywhere except Earth? If so, why is Earth conceptually bracketed off from "space"?


What?...you don't like it when someone "puts words" in your mouth??...well, guess what? neither do I.

You don't like it when people raise questions about your arguments?


Now if you would like to try again, and come up with a comparison that doesn't involve "things that we know exist", then be my guest.

Thank you... We know spiders exist. We don't know whether any particular basement has spiders until we go down into the basement and have a look. We know life exists in the universe. We won't know whether (for instance) Europa has life without close-up investigation using space probes.

R.A.F.
2012-Nov-17, 06:23 PM
The word "space" in your term "space aliens" means what?

Is the surface of a planet a place in space? Or does "space" just mean the space between planets?

Or does "space" mean anywhere except Earth? If so, why is Earth conceptually bracketed off from "space"?


I don't respond well to "what is is" type of responses....particularly when used to avoid "troublesome" realities.




You don't like it when people raise questions about your arguments?


What argument? I was simply pointing out the obvious...that your comparison was irrelevant to this discussion.

Why are you having such "difficulity" admitting that?




We know spiders exist. We don't know whether any particular basement has spiders until we go down into the basement and have a look.

Irrelevant to this discussion.




We know life exists in the universe.

Yes....as "we" are part of the Universe...what we don't know is if life exist elsewhere. Meaning that your "comparison" using spiders is irrelevant.

Colin Robinson
2012-Nov-17, 06:29 PM
What argument? I was simply pointing out the obvious...that your comparison was irrelevant to this discussion.

Why are you having such "difficulity" admitting that?

What seems "obvious" to you may not seem obvious to others.

That is one reason discussions like this happen...

Selfsim
2012-Nov-17, 06:30 PM
Yes, of course. It is asserting a conclusion that is not supported by evidence. If anything it is worse than saying, say, "There is definitely life at Tau Ceti," because at least that statement could, in principle, be confirmed or disproven.How can this statement be proven or disproven in practice?

R.A.F.
2012-Nov-17, 06:38 PM
What seems "obvious" to you may not seem obvious to others.

It isn't a matter of opinion...either your comparison is relevant, or it is not...

Colin Robinson
2012-Nov-17, 06:48 PM
It isn't a matter of opinion...either your comparison is relevant, or it is not...

Lets backtrack a little. My point about the spiders was in response to Paul Wally's point...


Correct, but it's usually the inferences drawn from lack of evidence that tend to become problematic, e.g. the fallacy that absence of evidence is evidence of absence.

Would you like to tell us what you think about that point, RAF?

R.A.F.
2012-Nov-17, 08:10 PM
Lets backtrack a little.

Nope...not interested in changing the subject. I've made my point. If any posters (besides you, of course :)) want to contest that point, then I'll be back to discuss that, otherwise, I'm out of this thread.

Swift
2012-Nov-17, 08:33 PM
That depends what you call an "alien".

So you like playing word games, eh?
Both of you knock it off.

Colin Robinson, you are playing word games. We all know what it meant by "alien" in the context of this tread, and your semantics discussion is a complete derailment.

R.A.F., you are just being needlessly aggressive and argumentative. Frankly, I think you like to pick fights with anyone who shows even a hint of a non-mainstream idea.

You want to discuss the linked article - then do say. Now knock off the rest of this nonsense.

Paul Beardsley
2012-Nov-17, 11:57 PM
How can this statement be proven or disproven in practice?

By travelling to Tau Ceti and taking a look. I didn't say it would be easy but it is at least conceivable, hence "in principle". OTOH if someone said there was no other life anywhere else in the universe, it would not be possible to prove the statement correct, even in principle, though it might be possible to prove it wrong.

The spider analogy is quite useful here. Just as the presence of cobwebs indicate that spiders are likely to be present, so too the presence of free oxygen in a planet's atmosphere would indicate that life-as-we-know-it is likely to be present. Whereas the absence of free oxygen, like the absence of cobwebs, indicates that the life form is unlikely to be present.

Colin Robinson
2012-Nov-18, 01:10 AM
By travelling to Tau Ceti and taking a look. I didn't say it would be easy but it is at least conceivable, hence "in principle". OTOH if someone said there was no other life anywhere else in the universe, it would not be possible to prove the statement correct, even in principle, though it might be possible to prove it wrong.

The spider analogy is quite useful here. Just as the presence of cobwebs indicate that spiders are likely to be present, so too the presence of free oxygen in a planet's atmosphere would indicate that life-as-we-know-it is likely to be present. Whereas the absence of free oxygen, like the absence of cobwebs, indicates that the life form is unlikely to be present.

I'm glad that someone finds my spider analogy useful!

What you say about oxygen may be right if you're thinking in terms of complex life. If life-as-we-know-it includes anaerobic microbes, Earth itself seems to have already had those for about one billion years before substantial amount of free oxygen started to appear in the Great Oxygenation Event (http://en.wikipedia.org/wiki/Great_Oxygenation_Event).

Paul Beardsley
2012-Nov-18, 05:17 AM
What you say about oxygen may be right if you're thinking in terms of complex life. If life-as-we-know-it includes anaerobic microbes, Earth itself seems to have already had those for about one billion years before substantial amount of free oxygen started to appear in the Great Oxygenation Event (http://en.wikipedia.org/wiki/Great_Oxygenation_Event).

Yes indeed, but I was talking about evidence, not proof. Similarly, the cobwebs in your cellar might have been made by spiders which have since departed; conversely, the absence of cobwebs does not rule out wolf spiders, trapdoor spiders and tarantulas.

Selfsim
2012-Nov-18, 05:22 AM
By travelling to Tau Ceti and taking a look. I didn't say it would be easy but it is at least conceivable, hence "in principle". Yep .. and "in practice" it is not conceivable as well, eh?
(The reason being that it is not presently practical to travel to Tau Ceti to conduct the tests, nor is it presently practical to transmit results back. In fact, the tests may not be able to be designed so as to eliminate false positives or false negatives, either .. depending on metabolism (if any) .. which is 'unknown' in advance of the testing).

The OP link talks about inferences between UFO sightings and aliens. I can't see much difference between this and our undemonstrated, believed abilities to remotely sense alien life over light year distances ..?? I mean .. we've sent life sensing tests to Mars, and still returned nothing conclusive, so where is the evidence that we can conclusively eliminate all other possible sources of supposed exo-'life signs' (like UFO sightings ≠ (necessarily) alien sightings)?

OTOH if someone said there was no other life anywhere else in the universe, it would not be possible to prove the statement correct, even in principle, though it might be possible to prove it wrong.Which would be just about the same as saying: "life is rare and there is other life elsewhere in the universe" … because it is also not possible to disprove it.


The spider analogy is quite useful here. Just as the presence of cobwebs indicate that spiders are likely to be present, so too the presence of free oxygen in a planet's atmosphere would indicate that life-as-we-know-it is likely to be present.
Whereas the absence of free oxygen, like the absence of cobwebs, indicates that the life form is unlikely to be present.So, Mars has free oxygen, Ganymede does, Europa has dissolved (free) Oxygen (model based), the rings of Saturn do, Abell 30 does, etc .. Therefore, life-as-we-know-it is likely to be present there?
(I realise you did reference a 'planet's' atmosphere .. so you may not agree with the moons and the latter two, however, at the moment I can't see much difference 'in principle' .. ie: as far as the point goes ..(??))

If life-as-we-know-it is not found in these locations, (particularly in the case of Mars), then the generalised statement is falsified, and thus the presence of free oxygen in a planet's atmosphere would not indicate that life-as-we-know-it, is likely to be present(??)

Paul Wally
2012-Nov-18, 03:56 PM
Nah ... the real problem is when folks succumb to the temptation of incessantly dwelling on speculative discussions, which then conjure up inferences about the 'likelihood' or 'prevalence' of exo-life throughout the obs. universe. (Which then, for some strange, inexplicable reason, seems to then reduce to 'rareness' of certain lifeforms, or rareness of remotely detectable 'bio-signs'... ie: the Fermi paradox, and the ensuing counter 'explanations' for the apparent lack of remnants, or present evidence).



You should perhaps investigate why other people engaging in what you call "speculative discussion" is a problem to you. How does their speculation become your problem?

Anyway, there are different kinds of likelihood statements. One is an absolute likelihood statement which asserts a likelihood based on subjective intuition. That's just people expressing their opinion on the matter, and it doesn't bother me much, why should it? Since it's just their opinion based on some intuition they may have, there's no point in arguing because there's no data either way that could decide one way or the other.

There is however a different kind of likelihood statement based on pure mathematical reasoning, and that is a conditional probability statement. Conditional probability means that if some conditions hold true then the probability follows logically. For example we could say if there are a million civilizations like us in the galaxy with an equiprobable distribution over the 200billion stars then that would be 1 star in every 200 000. We could then proceed to make calculations like the average distance between civilizations, and from that we could then do interesting comparisons like comparing how far radio signals of some power level could travel in comparison to the average distances, or how much power a radio signal must have at the transmitter end in order to be detectable over the aforementioned average distance. It gets more complicated, but it's for instance possible to calculate the probability of detecting a radio signal of some power level (with current SETI technology), from a random star, if there are a million civilizations transmitting at that power level.

The Drake equation defines a space of possibilities and therefore provides a framework for formulating different conditional probabilities, but it's not an empirical equation that tells us anything about what the actual state of affairs is. Included is every possibility, from zero life in the galaxy to an intelligent civilization in every solar system. The truth is somewhere in that finite space of possibilities.

With regard to the Fermi paradox, the above-mentioned kind of calculations could be used to work out upper bounds on the number of civilizations with radio communications of a certain power level. For example what is the largest number of civilizations that could exist such that SETI still couldn't detect them with sufficient probability. Or we could work out a lower bound. What is the least number of civilizations such that we should have detected a signal by now. These calculations would also be conditional on the radio power level and that they are using radio at all etc. They could be using subspace transmissions, but that would be an example of speculation. :)

R.A.F.
2012-Nov-18, 04:02 PM
If any posters want to contest that point, then I'll be back to discuss that

Per this post, I will now continue...



The spider analogy is quite useful here.

It begins from a flawed premise....that spiders and aliens both exist...we do have conclusive proof of one, but not the other.


Lets see if I can make it any clearer...allow me to substitute a few words from your own post...


Just as the presence of cobwebs indicate that (something that we KNOW exists) are likely to be present, so too the presence of free oxygen in a planet's atmosphere would indicate that (something we DON'T know exists) is likely to be present.


See what I'm saying?....if not, please explain why not.

Selfsim
2012-Nov-18, 08:39 PM
Conditional probability means …
…
The truth is somewhere in that finite space of possibilities.
...
calculations could be used to work out upper {and lower} bounds ...
...Statistics don't reveal 'truths'. Even a likely outcome is not a dead certainty.

Of all the UFO sightings here on Earth, you think we could calculate the upper and lower bounds constraining the likelihood that one, or some of them, contained aliens, eh?

Statistical 'calculations' with no evidence basis, merely serve to obfuscate reality and support fixed beliefs ... which it seems, is precisely where over-speculation which trivialises the lack of initial evidence, may have led in this instance.

The OP's linked article by UFO investigation expert David Clarke, makes the point that evidence is the only thing which matters, and en-masse technology to date, has actually disproven the alien activity idea. Statistical calculations are irrelevant to this argument.


but that would be an example of speculation. :) .. and the rest of your calculations wouldn't be, eh?

Jens
2012-Nov-19, 01:48 AM
What about the words in the title of this thread (from the headline of the article quoted) "aliens don't exist"? Do they also constitute an extraordinary claim?


It certainly would be an extraordinary claim, and in fact I made that very point in my first post in this thread. I don't think that's really what the headline writer was trying to say though, I think it's just poorly worded.

Jens
2012-Nov-19, 01:52 AM
Yes, of course. It is asserting a conclusion that is not supported by evidence. If anything it is worse than saying, say, "There is definitely life at Tau Ceti," because at least that statement could, in principle, be confirmed or disproven.


This is a bit of a nitpick, but I think that's not quite correct. It could in principle be confirmed, but not disproven, because there would always be the chance that life exists in some form that we can't detect.

Paul Beardsley
2012-Nov-19, 07:05 AM
This is a bit of a nitpick, but I think that's not quite correct. It could in principle be confirmed, but not disproven, because there would always be the chance that life exists in some form that we can't detect.

I was envisaging either a planet teeming with life, or a rocky, moonlike world (or no world at all) with nothing in between, but yes, you're right.

Paul Wally
2012-Nov-19, 05:20 PM
Statistics don't reveal 'truths'. Even a likely outcome is not a dead certainty.

Depends on what you mean by 'statistics', empirically gather data points or mathematical probability theory. I was referring to the latter, which does reference intrinsic truths of probability. And a likely outcome is exactly what it says, a likely outcome. In probability theory the likelihhood of the outcome is the certainty. If there really is a 50% chance then it is certain that it is a 50% chance.


Of all the UFO sightings here on Earth, you think we could calculate the upper and lower bounds constraining the likelihood that one, or some of them, contained aliens, eh?

Well, we don't even know whether many of those UFO sightings were sightings of actual containers, not to mention containers of aliens. It's completely different case from calculating probabilities from what we know about propagation of radio waves through space.


Statistical 'calculations' with no evidence basis, merely serve to obfuscate reality and support fixed beliefs ... which it seems, is precisely where over-speculation which trivialises the lack of initial evidence, may have led in this instance.

This looks like bunch of sweeping generalizations to "obfuscate reality" for yourself. What specifically are you referring to?



.. and the rest of your calculations wouldn't be, eh?

I guess not. Are radio waves speculative?

Selfsim
2012-Nov-19, 09:13 PM
Paul;
Are you saying anything of relevance to the thread topic? (If so, I apologise in advance. I must have missed it) ...

Conditional probability means that if some conditions hold true …{etc}… And the conditional probability statement says nothing about the veracity of that assumption, so why are we even discussing this?

A.DIM
2012-Nov-19, 10:48 PM
Since there is no evidence, the default answer MUST be no alien visitors.


...or do you disagree?

I disagree.
"We don't know" is the only, and default, answer we have, RAF. True skepticism is withholding judgment in the face of insufficient evidence.

A.DIM
2012-Nov-19, 10:52 PM
That makes the assumption that the 2 ideas, (that aliens have visited, or that aliens have not visited), are somehow equally likely...they are not.

I'm interested in hearing how you quantified the 2 ideas, so that we know which is more likely.

pzkpfw
2012-Nov-19, 11:04 PM
"We don't know" is the only, and default, answer we have, RAF. True skepticism is withholding judgment in the face of insufficient evidence.

I would disagree with that.

"When you hear hoofbeats behind you, don't expect to see a zebra." Theodore Woodward

Or as often stated: "When you hear the sound of hoofbeats in the night, think first of horses not of zebras", as, for example on the NZ Skeptic website: http://www.skeptics.org.nz/ who I'd note state (my bold) "Skeptics look for the simplest explanations first, but are willing to consider other possibilities in the light of unambiguous evidence".

So when some unambiguous evidence for extra-terrestrial visitors comes along, sceptics will consider the possibility.

tnjrp
2012-Nov-20, 07:00 AM
I would say that "we can't be certain" is the default answer of a skeptic when faced with insufficient evidence for a proposition. However not all things that we can't be certain of are equally likely to have a factual existence, even if the exact numbers thereof cannot be calculated.

Selfsim
2012-Nov-20, 09:07 PM
I would say that "we can't be certain" is the default answer of a skeptic when faced with insufficient evidence for a proposition. However not all things that we can't be certain of are equally likely to have a factual existence, even if the exact numbers thereof cannot be calculated.Hi tnjrp;
Well, I guess the interesting question is how do we then support that: "not all things that we can't be certain of are equally likely to have a factual existence"?

Inference based philosophy is one way (inductive, abductive and deductive logic). But I wouldn't classify any of these with anywhere near the same 'status' as the role observational/measurement plays in physical science. Inductive reasoning can lead to either correct or incorrect conclusions (once physically tested).

I'm apprehensive about a general, unsupported assertion of non-equality. Artifical constraints, (posits, principles, speculation, etc), seem to have to be accepted before inequality appears(??)

Paul Wally
2012-Nov-20, 09:28 PM
… And the conditional probability statement says nothing about the veracity of that assumption, so why are we even discussing this?

I actually agree with you on that one. The conditional probability statement says nothing about the veracity of the condition (the 'if' part). "Assumption" is a bit strong though, because it's not something believed to be either true or false. The purpose of such a mathematical investigation will be to explore the implications of the condition, rather than the truth of the conditions. However, it could happen that the implications of the condition contradict empirical findings, implying reductio ad absurdum.



Are you saying anything of relevance to the thread topic? (If so, I apologise in advance. I must have missed it) ...

I was responding to what you had to say on 'likelihood' in post #27. I'm trying to illustrate that not all likelihood talk is of the speculative kind that you're referring to here:


Nah ... the real problem is when folks succumb to the temptation of incessantly dwelling on speculative discussions, which then conjure up inferences about the 'likelihood' or 'prevalence' of exo-life throughout the obs. universe. (Which then, for some strange, inexplicable reason, seems to then reduce to 'rareness' of certain lifeforms, or rareness of remotely detectable 'bio-signs'... ie: the Fermi paradox, and the ensuing counter 'explanations' for the apparent lack of remnants, or present evidence).

Paul Beardsley
2012-Nov-20, 09:39 PM
How about this?

Our knowledge about the prevalence of extraterrestrial life is zero.

But if life as we know it does exist, it is more likely to be located in the goldilocks zone of a star than below the star's surface.

Colin Robinson
2012-Nov-20, 11:16 PM
I would disagree with that.

"When you hear hoofbeats behind you, don't expect to see a zebra." Theodore Woodward

Or as often stated: "When you hear the sound of hoofbeats in the night, think first of horses not of zebras",

This makes sense up to a point, but can be taken too far, especially when you're looking at unfamiliar territory.

A historical example — in the 17th century, Dutch seafarers found islands near the west coast of Australia, and noticed populations of a small furry animal on the islands. One captain described the animal as a wild cat. Another took a closer look at the animal — a herbivore with a round back, a long nose and tail — and described it as a large rat.

The 17th century explorers didn't know it, but the creature they had found was neither cat or rat, nor a close relative of either, but a creature more exotic than a zebra. It is the quokka, a smaller relative of the kangaroo. But in those days kangaroos were unknown to European zoology...


as, for example on the NZ Skeptic website: http://www.skeptics.org.nz/ who I'd note state (my bold) "Skeptics look for the simplest explanations first, but are willing to consider other possibilities in the light of unambiguous evidence".

So when some unambiguous evidence for extra-terrestrial visitors comes along, sceptics will consider the possibility.

Surely unambiguous evidence is enough to make a proposition an established fact, not just a possibility to consider?

I'd suggest that when considering comparatively unfamiliar territory — especially other planets and moons, but also Earth billions of years ago — it's a good idea to consider a range of propositions which are consistent with whatever ambiguous evidence we may have. And then to consider what sort of unambiguous evidence we would need to find, in order to either verify or falsify particular propositions...

tnjrp
2012-Nov-21, 06:21 AM
@ Selfism

I assume you aren't at all "apprehensive" of "specified assertions of non-equality" however. Unless I'm much mistaken, you are willing to concede that while we may still find a new species of a largeish mammal living somewhere on Earth, it's not quite as likely to be an invisible pink unicorn as a member of the deer family.


Inference based philosophy is one way (inductive, abductive and deductive logic). But I wouldn't classify any of these with anywhere near the same 'status' as the role observational/measurement plays in physical science. Inductive reasoning can lead to either correct or incorrect conclusions (once physically tested)Inference doesn't need to be based on philosophy as such. It can quite easily be based on what on what has been previously established by empirical observation and tested theories that explain those observations. This is in fact one way how science advances as such extrapolation is strongly involved in formulating hypotheses.

Selfsim
2012-Nov-21, 07:05 AM
@ Selfism

I assume you aren't at all "apprehensive" of "specified assertions of non-equality" however. Unless I'm much mistaken, you are willing to concede that while we may still find a new species of a largeish mammal living somewhere on Earth, it's not quite as likely to be an invisible pink unicorn as a member of the deer family.Sure ... somewhere else today, I made a post which clarified some my own bounds on all this. We seem to have a bunch of folk who spend a lot of time wrangling with Conspiracy Theorists, and some ATMers, who, I think, are dealing with more extreme aspects, than I was perhaps initially envisaging. I was assuming we were discussing speculation bounded by established scientific theory and process. Within this scope, I think disparities between various speculative propositions are far less obvious, and can be frequently balanced on the basis of existing theory and hypothesis. The paucity of available empirical data, frequently results in an inability to distinguish what is more 'probable' or 'improbable' ...

I might add that I'm happy to say there'll be no arguments from me about ruling out notorious 'invisible pink unicorns'!


Inference doesn't need to be based on philosophy as such. It can quite easily be based on what on what has been previously established by empirical observation and tested theories that explain those observations. This is in fact one way how science advances as such extrapolation is strongly involved in formulating hypotheses.In the case of exo-life however, it is extremely difficult for us to eliminate the anthropocentric bias. Very specific tests, (and resulting data types), are needed to do this and it doesn't seem to matter how much inductive, abductive or deductive logic is applied to established theory, at the end of the day, a single instance of different Chemistry or non-Standard Genetic Code based life, is required to separate the 'chalk-from-the-cheese'.

I might also add that Biological Science demands empirical test results and weights these far more highly than inferences taken from theory. This aspect requires far greater emphasis than appears to be forthcoming from those well versed in Astrophysics, especially when discussing 'equality/inequalities' of exo-life speculation.

tnjrp
2012-Nov-21, 08:03 AM
The paucity of available empirical data, frequently results in an inability to distinguish what is more 'probable' or 'improbable' ...

I might add that I'm happy to say there'll be no arguments from me about ruling out notorious 'invisible pink unicorns'!So you are happy with dismissing an invisible pink unicorn out of hand since it's a specific "far-out claim", but in the case of invisible lifeforms in general, due to paucity of evidence, nothing much can be said in regards to if finding one is as likely or less likely than finding a regular visible new lifeform?


I might also add that Biological Science demands empirical test results and weights these far more highly than inferences taken from theoryI wasn't aware that biology is so logical positivist in attitude that extrapolation as a tool for generating hypotheses is not proper biology, but since I'm not a biologist myself I guess I'll take your word for it. That certainly would seem to relocate not only your pet peeve astrobiology but also abiogenesis studies completely outside of biology at the very least at this present time.

Selfsim
2012-Nov-21, 10:33 AM
So you are happy with dismissing an invisible pink unicorn out of hand since it's a specific "far-out claim", but in the case of invisible lifeforms in general, due to paucity of evidence, nothing much can be said in regards to if finding one is as likely or less likely than finding a regular visible new lifeform?Hmm ... now if we're still running with the possibility that we 'may still find a new species of a largish mammal living somewhere on Earth', then I think I'd probably be dismissing 'invisible lifeforms in general' on the same basis as the dismissal of 'invisible pink unicorns'. Mind you, the specification: 'invisible pink unicorns' is an oxymoron, since 'pink' and 'invisible' are normally, mutually exclusive attributes of the EM spectrum aren't they? Almost the same goes for 'invisible lifeforms in general' when we're discussing the possibility of finding a 'largish mammal'(??)

This is a highly useful exercise for me, and I thank you for it ... it has certainly gotten me thinking ...
My original contention was that artificial 'constraints' (or definitions, speculations, posits, theories etc) seem to have to be accepted, before (qualititative) inequality appears. I think that may be exactly what I'm doing in dismissing the two propositions(??) .. interesting ...



I might also add that Biological Science demands empirical test results and weights these far more highly than inferences taken from theory I wasn't aware that biology is so logical positivist in attitude that extrapolation as a tool for generating hypotheses is not proper biology, but since I'm not a biologist myself I guess I'll take your word for it. Its interesting ... since predictions in Physics are logically based, the incidence of 'data-less predictions' (ie: speculation), seems to be much higher than in the biological sciences. One might even say that due to the far greater complexity of biology, predictions are usually probability based, and are therefore built on a foundation of existing data.

In the earliest days of genetics, 'gene finding' was based on experimentation on living cells and organisms. Statistical analysis of the rates of recombination of several different genes could determine their order on a certain chromosome, and this was then combined to create a genetic map which predicted the rough location of known genes relative to each other.

Compare this with Physics predictions that are based on postulates alone, where there was no existing empirical data at the time, such as the bending of light by gravity.

There's a fundamental difference in approach (caused by the complexity of the subject matter) and Astrobiology has to accept the greater demand for an empirical basis, when raising speculative hypotheses.


That certainly would seem to relocate not only your pet peeve astrobiology but also abiogenesis studies completely outside of biology at the very least at this present time.Perhaps a somehwat extreme measure, but, maybe .. and that would also be kind of like removing the 'biology' suffix (ie: the 'heart') from 'Astrobiology' (ie: the 'body').

tnjrp
2012-Nov-21, 11:46 AM
Mind you, the specification: 'invisible pink unicorns' is an oxymoron, since 'pink' and 'invisible' are normally, mutually exclusive attributes of the EM spectrum aren't they?Well, it almost always eventually comes down to "invisible pink unicorn doesn't exist" being a truism (or a strawman or whathavewe) since rather obviously it can't have a colour if it's invisible. However you cannot infer from the common denomination of the hypothetical species alone that it cannot become visible occasionally and appear pink when it does so. This is obvious when looking at how critters are named in general, see for example the common name for Carcharodon carcharias.


Almost the same goes for 'invisible lifeforms in general' when we're discussing the possibility of finding a 'largish mammal'(??)So "invisible lifeform" (as in a lifeform that should be large enough to be seen by an average human but isn't due to as-of-yet-unspecified reasons) is still a specific enough claim that it can be "almost" dismissed out of hand? I'm trying to understand where you draw a line as to general claim where it's dangerous to say that "it's likely/unlikely that X" as opposed to a specific claim where it's safe to assign a tentative likelihood. Is it really just dependant on the attributes relating to the claim, such as invisibility (which is certainly difficult although not perhaps entirely impossible to accomplish) in this case?

Jerry
2012-Nov-21, 01:41 PM
In these UFO scenarios, why don't the aliens ever want "Tribal Artwork" or land for development? They seems to make it to the point of stealing women or water, but strangely never both at the same time. :)

Duck tape. Don't forget they envy duck tape.

Paul Wally
2012-Nov-21, 03:38 PM
Its interesting ... since predictions in Physics are logically based, the incidence of 'data-less predictions' (ie: speculation), seems to be much higher than in the biological sciences. One might even say that due to the far greater complexity of biology, predictions are usually probability based, and are therefore built on a foundation of existing data.

In the earliest days of genetics, 'gene finding' was based on experimentation on living cells and organisms. Statistical analysis of the rates of recombination of several different genes could determine their order on a certain chromosome, and this was then combined to create a genetic map which predicted the rough location of known genes relative to each other.

Compare this with Physics predictions that are based on postulates alone, where there was no existing empirical data at the time, such as the bending of light by gravity.

There's a fundamental difference in approach (caused by the complexity of the subject matter) and Astrobiology has to accept the greater demand for an empirical basis, when raising speculative hypotheses.

Perhaps a somehwat extreme measure, but, maybe .. and that would also be kind of like removing the 'biology' suffix (ie: the 'heart') from 'Astrobiology' (ie: the 'body').

The above simply doesn't reflect the reality of biological research. There is as much, if not more, hypothesizing in biology as there is in physics. The field of molecular biochemistry would hardly have existed today were it not for the scientific process of postulating hypotheses and testing them. How do you think complex biochemical processes like protein synthesis are discovered without postulating an hypothesis first? It's virtually impossible, to discover these processes and mechanisms without formulating hypotheses precisely because the cell environment is so incredibly complex. Without an hypothesis we wouldn't know what variables to isolate and investigate in more detail, and without isolated variables we don't have any statistics either.

Selfsim
2012-Nov-21, 08:40 PM
The above simply doesn't reflect the reality of biological research. There is as much, if not more, hypothesizing in biology as there is in physics. The field of molecular biochemistry would hardly have existed today were it not for the scientific process of postulating hypotheses and testing them. How do you think complex biochemical processes like protein synthesis are discovered without postulating an hypothesis first? It's virtually impossible, to discover these processes and mechanisms without formulating hypotheses precisely because the cell environment is so incredibly complex. Without an hypothesis we wouldn't know what variables to isolate and investigate in more detail, and without isolated variables we don't have any statistics either.I was referring to the greater credence given to the empirical test results end of the process, (following the scientific hypotheses precursor) …

I might also add that Biological Science demands empirical test results and weights these far more highly than inferences taken from theory.The speculative phase in biological sciences is regarded more as: 'Yeah? ... (yawn) ... show me the lab results (and/or trial results)!'

Another eg: Darwin predicted, on the basis of Evolution and Natural Selection, that a plant with a deep flower would require an animal to have evolved, which would have a long snout to feed from it. After Darwin's time, a certain moth was discovered which matched the prediction. Note that there was existing 'matching' (symmetry-inferred) data, (the plant), in order to make the prediction. There was no such empirical data, with the bending of light prediction I mentioned previously .. (I'm sure there are other examples of this in Physics).

There is something of relevance to notice here in the comparison of how Physics works, as compared with Biology .. and it impacts the approach to be taken in Astrobiology .. and I think its missing in that field (or at least, 'toned down' markedly(??)).

AstroRockHunter
2012-Nov-21, 10:29 PM
Since there is no evidence, the default answer MUST be no alien visitors.


...or do you disagree?

R.A.F.

Others have disagreed with this, and I must say that I disagree also.
However, my reason for disagreeing is that by accepting your default answer, one would be proving a negative which is a logical fallacy.

Selfsim
2012-Nov-21, 10:34 PM
So "invisible lifeform" (as in a lifeform that should be large enough to be seen by an average human but isn't due to as-of-yet-unspecified reasons) is still a specific enough claim that it can be "almost" dismissed out of hand?Hmm … 'invisibility' is a problem …


I'm trying to understand where you draw a lineSo am I .. I'm not sure I've put my finger on it, yet … :)
… as to general claim where it's dangerous to say that "it's likely/unlikely that X" as opposed to a specific claim where it's safe to assign a tentative likelihood. Is it really just dependant on the attributes relating to the claim, such as invisibility (which is certainly difficult although not perhaps entirely impossible to accomplish) in this caseY'know, I think the problem is being cornered into having to pass judgement on something which is, 'gut-feel', fundamentally unsupported (/unsupportable). Taking a stand on 'unknown' being a valid state for knowledge to be in, I think, is honest and unbiased. The counter-arguments coming from the 'pink and invisible' claimant, are so uninteresting (for me) that I lose interest within almost the first sentence ..

The more I think about the reasons for 'dismissal' of the concept of unsupportable imbalance between 'likely and unlikely', the more I come up with the answer 'no reason' .. which, I think, is perfectly consistent with what I'm saying … I'm deliberately, desperately trying to not make the claimaint 'wrong' (by acting out of my own unjustifiable beliefs, and seeking the 'buzz' which usually comes from being 'right') .. its just that there's no value forthcoming from such a discussion .. so I can walk away from it, labelling it as more entertainment, sci-fi, (or some other mindless, low value past-time).

Maybe this is why I don't pay much attention to the Conspiracy Forum(??) ..

As to the difference between general vs specific, it comes back to what constitutes a generalised theory in science. It is (sorry .. just verbalising here) … an explanation for a phenomenon, (or a class of phenomena). Using a generalised theory, as the basis for passing judgement on some claim, is not really, (for me), what science is about. People do that. Courts of Law do it that .. politicians do that by shaping the perspectives of the masses … and all that's external to Science's purpose (for me).

A Law in Physics is about as 'firm' a basis for the (human) purpose of judgement, as it gets. But even Laws are still open to being restated in the light of contrary examples being found. Even with the firmness attributable to this 'weight', it is still inappropriate for being used to demonstrate 'truth' because it can easily be demonstated that even a 'likely' outcome, isn't a dead certainty.

.. I'm trying hard here .. I appreciate your 'coaching' assistance .. (always open to more of that …)
:)

I recognise its a fine line I'm treading also .. and one I think many ATMers and pseudoscientists cite as well, (hence perhaps the alarms bells going off with those familiar with the argument). But deliberately not stepping in, to fill the gap left by sticking with the 'unknown' line, is what distinguishes this from ATM or pseudoscience. It is a very clear line for me .. and there are a lot of distinctions behind it.

Cheers

Selfsim
2012-Nov-21, 10:50 PM
R.A.F.

Others have disagreed with this, and I must say that I disagree also.
However, my reason for disagreeing is that by accepting your default answer, one would be proving a negative which is a logical fallacy.Hi AstroRockHunter;
Well, in the light of what I just posted, I can see the consistency of where you're coming from here. Its interesting that you are forced into having to cite a reason in order to defend what is probably a gut-feel, which goes against some fundamental philosophical commitment to not use logical fallacies .. (which is all fine .. we all make our own particular, sometimes deliberate, sometimes subconscious, commitments on priorities …). I've also recently found that the grounds set by some counter-arguments should actually allow for the legitimate admission of logically fallacious arguments! I suppose proceediing with one, would also be a demonstration of consistency (or integrity in respect of the bounds of such a discussion, eh?)

However, from hereon, it seems that 'agreement' might the only way to resolve any gaps. Is agreement science, or philosophy?

TooMany
2012-Nov-27, 07:20 PM
Getting back to the subject of this thread, the sound bite is "aliens don't exist". If you read the article what's actually being argued is that the claimed evidence for alien visitation (lights in the sky, marks on the ground, dead cows, strange glows, witnesses, abductions) is not really evidence of alien visitation. However, going on from that to conclude that "aliens don't exist" or even that "aliens have never visited earth" is without foundation.

I could make another (speculative but nevertheless plausible) argument that aliens do exist and that in all probability they have visited earth. First I suggest that life (organic life as we know it) emerges pretty much where ever the opportunity exists for it to arise. We now know that planetary systems are quite common and that occasionally one will contain a planet suitable to create and support life. We also know that biological evolution leads to increasingly complex nervous systems which eventually results in a species like our own. We as a species are already taking our first baby steps beyond our planet and there is every indication that we will pursue interstellar travel despite the patience required to get something back from the endeavor.

At the same time we are beginning to create artificial intelligence which because of various advantages over biological systems will far exceed our abilities as organics beings. In other words we can foresee a transformation of biological intelligence into a new non-biological from of life. I further suggest that this non-biological life is for practical purposes immortal (although not necessarily fully so) and possesses the patience needed for interstellar travel. Moreover this non-biological intelligence is perfectly capable of mass production of cognitive machines capable of exploring the galaxy.

The galaxy is far older than the sun and earth and over that time the evolution of such intelligent life capable of interstellar travel has undoubtedly occurred many times. So we should expect that the galaxy has already been explored even if for no other purpose than to take a census. To expect that we should find evidence of that is naive. Perhaps the intelligent life that evolves and explores the galaxy has no interest in being detected by us and can easily hide using technology far in advance of our own. Perhaps a "prime directive" ethic does develop or has even been enforced by a founding race in the galaxy. It would require some rather sloppy work on the part of this advanced intelligent race to sprinkle evidence around of their existence, if they prefer not to.

As to why SETI has not found anything may not be difficult to answer. It's because it would require a rare coincidence that another intelligent civilization would exist near enough to detect while also being at the same stage of advancement that we ourselves are (i.e. using broadcast radio and what not). An overlap of a few centuries is very small in comparison with the billions of years required for intelligent life to evolve.

There are many other possible explanations of the Fermi paradox as well that don't require life as we know on earth to be an extreme rarity. I have just picked one as an example. Regardless of our failure to find aliens, what we already know about the universe is pretty good indication that they should exist. The solution to the Fermi paradox is extremely unlikely to be that we are alone, so I think it is worthwhile to consider other possibilities.

Absence of evidence is not dependable evidence of absence.

R.A.F.
2012-Nov-27, 08:24 PM
I could make another (speculative but nevertheless plausible) argument that aliens do exist and that in all probability they have visited earth.

When you post that something is plauable/probable, then you are not speculating, you are advocating.


We don't even know if aliens exist elsewhere, and you are saying that it is "probable" that they have visited Earth?....you don't see anything wrong with that?

TooMany
2012-Nov-28, 12:07 AM
When you post that something is plauable/probable, then you are not speculating, you are advocating.


We don't even know if aliens exist elsewhere, and you are saying that it is "probable" that they have visited Earth?....you don't see anything wrong with that?

No, nothing at all. Let's call it a thought experiment based on what we do know. I explained the line of reasoning that leads to the probability. Can you tell me what's "wrong" with it?

Is suggesting that something is plausible and even probably advocating? Are you using "advocating" to connote "promoting"? Like I have some mission with an unstated motive?

Not at all, I just think that the hypothesis that there are no aliens is a very remote possibility so I'm thinking about why we haven't encountered them, i.e. the so-called Fermi paradox.

Jens
2012-Nov-28, 12:09 AM
When you post that something is plauable/probable, then you are not speculating, you are advocating.
We don't even know if aliens exist elsewhere, and you are saying that it is "probable" that they have visited Earth?....you don't see anything wrong with that?

I don't see anything wrong with it, personally. I am doing the same thing. I am saying that I do not know the truth, but my belief (not in the sense of religious belief, but as in "I think that") based on the evidence I'm aware of is that life probably exists elsewhere and that aliens have never visited the earth. If somebody wants to come up with a different belief based on their reading of the evidence, I can't see why that would be a problem.

TooMany
2012-Nov-28, 12:35 AM
I don't see anything wrong with it, personally. I am doing the same thing. I am saying that I do not know the truth, but my belief (not in the sense of religious belief, but as in "I think that") based on the evidence I'm aware of is that life probably exists elsewhere and that aliens have never visited the earth. If somebody wants to come up with a different belief based on their reading of the evidence, I can't see why that would be a problem.

Why do you believe that aliens have never visited earth?

Selfsim
2012-Nov-28, 02:08 AM
Why do you believe that aliens have never visited earth?
Not attempting to answer on behalf of Jens, (please forgive me Jens ..) … but as an example of what I'd think would be a good answer to that question, (following what Jens posted), would be: 'myeah … no real reason'. :)

Cheers

R.A.F.
2012-Nov-28, 04:01 AM
Is suggesting that something is plausible and even probably advocating?

If we are talking about alien flying saucers visiting Earth as we speak, then yes...you are advocating.



Are you using "advocating" to connote "promoting"? Like I have some mission with an unstated motive?

I have no idea what your motive might be...



I just think that the hypothesis that there are no aliens is a very remote possibility...

See, that's the thing..you take something, a question that might not even be answered in our lifetimes, and you make it PROBABLE.

You are not speculating...you are making statements of fact.



....so I'm thinking about why we haven't encountered them, i.e. the so-called Fermi paradox.

Oh, I got an easy answer for ya....but you're not going to like it...

Sure...literally billions of other civilizations....scattered throughout the Universe, but only one per Galaxy.


Since there is no evidence whatsoever for ET life, that last sentence is just as "probable/plausable" as anything I've seen proposed here.....

R.A.F.
2012-Nov-28, 04:04 AM
Why do you believe that aliens have never visited earth?

More telling would be, why do you believe what you believe, because you seem to be starting off from a very "alternative" viewpoint.

Jens
2012-Nov-28, 04:10 AM
Why do you believe that aliens have never visited earth?

As a result of a combination of a number of factors. 1, the distance involved is so great that I doubt it is realistic. 2, there clearly aren't any now, which is understandable given 1 but would sort of need explaining if there had been visits in the past. And 3, there is no evidence for it, so I see no need to go against the conclusion reached from 1 and 2.

Hornblower
2012-Nov-28, 02:22 PM
My educated guess is that numerous lifeforms comparable to us or even more advanced are scattered throughout the universe, but that the formidable energy requirements for an interstellar voyage, not to mention an intergalactic one, have precluded any visit to Planet Earth.

I can envision a scenario in which an alien spacecraft landed millions of years ago and then departed without leaving any hardware behind. Ordinary weathering and biosphere activity then obliterated all traces of any impact the spacecraft made on the ground. That would be a good hypothetical example of absence of evidence not necessarily being valid evidence of absence.

eburacum45
2012-Nov-28, 04:07 PM
I can envision a scenario in which an alien spacecraft landed millions of years ago and then departed without leaving any hardware behind. Ordinary weathering and biosphere activity then obliterated all traces of any impact the spacecraft made on the ground. That would be a good hypothetical example of absence of evidence not necessarily being valid evidence of absence.
That is correct. Even if alien spacecraft landed here once every million years, but left no traces behind, they would have been here thousands of times in our planet's long history and we would be none the wiser. Of course that implies that each one of those thousands of visits was equally careful to leave no traces; but on a planet like the earth, where the surface is constantly renewed by geological processes, that could probably be achieved quite easily.

One thing that might last for a long time would be biological traces- if the aliens emptied their garbage-bin or toilet tank on the surface, then some alien bacteria might have survived. The possibility remains that we might all be descended from such an unintended consequence.

TooMany
2012-Nov-28, 04:42 PM
If we are talking about alien flying saucers visiting Earth as we speak, then yes...you are advocating.


Well, I have no idea about the "as we speak" speak part. All I'm doing is extrapolating to suggest the possibility/probability of visitation at some time or other.



See, that's the thing..you take something, a question that might not even be answered in our lifetimes, and you make it PROBABLE.

You are not speculating...you are making statements of fact.


Here is yet another possible/probable speculation. It appears that terrestrial (rocky) planets like earth are found in other systems. I will speculate with some confidence that the mineral quartz exists on the surface of most of these planets. Now this is also a question that will probably not be answered in our lifetimes; do you deny that it is probable?



Oh, I got an easy answer for ya....but you're not going to like it...

Sure...literally billions of other civilizations....scattered throughout the Universe, but only one per Galaxy.


Since there is no evidence whatsoever for ET life, that last sentence is just as "probable/plausable" as anything I've seen proposed here.....

I don't see why this would be as just as probable at all. Why would there at most one or exactly one civilization per galaxy? What argument do you propose for that?

TooMany
2012-Nov-28, 05:01 PM
As a result of a combination of a number of factors. 1, the distance involved is so great that I doubt it is realistic. 2, there clearly aren't any now, which is understandable given 1 but would sort of need explaining if there had been visits in the past. And 3, there is no evidence for it, so I see no need to go against the conclusion reached from 1 and 2.

Imagine a scientist in the eighteen century. At that time they knew the distance of the moon. Don't you think they probably would have concurred that "the distance involved is great that I doubt it is realistic" to travel to the moon? At that time I wonder whether anyone had even thought about the possibility of building a big enough rocket to go to the moon.

What is the foundation for "they clearly aren't [visiting earth] now"? For 3 "there is no evidence for it", I'd simply repeat that absence of evidence is not firm evidence of absence. Your assumption seems to be that if they did visit us here and now, we would know. How would we know, if they didn't want us to know? We're talking about technology far superior to our own, right?

TooMany
2012-Nov-28, 05:23 PM
One thing that might last for a long time would be biological traces- if the aliens emptied their garbage-bin or toilet tank on the surface, then some alien bacteria might have survived. The possibility remains that we might all be descended from such an unintended consequence.

That applies only if the aliens never took the evolutionary leap beyond their original biological form. Given the progress that has been made in my own lifetime with computers, I have little doubt (unless mankind suffers a major setback) that will we create cognitive "machines". These will eventually be beings of greater intellectual stature than ourselves without our biological limitations. I'm not saying we are anywhere near that yet, but we will get there, perhaps within the next century even.

Human brains work quite differently from computers however there is no neurological process in the brain that is impossible to mimic with electronics. People right now are studying the structure of the brain and attempting to create hardware that mimics it. One difference will be that instead of a synapse operating with a 1 millisecond delay there will be synapses reacting with < 1 nanosecond delay (one million times faster). What happens then is anybody's guess. My main point is that our thinking is anthropomorphic when we assume that aliens would arrive as bio-chemical life forms.

Paul Beardsley
2012-Nov-28, 05:30 PM
Imagine a scientist in the eighteen century. At that time they knew the distance of the moon. Don't you think they probably would have concurred that "the distance involved is great that I doubt it is realistic" to travel to the moon? At that time I wonder whether anyone had even thought about the possibility of building a big enough rocket to go to the moon.

Add the word "again" and you're pretty much describing any 21st century scientist!


What is the foundation for "they clearly aren't [visiting earth] now"? For 3 "there is no evidence for it", I'd simply repeat that absence of evidence is not firm evidence of absence. Your assumption seems to be that if they did visit us here and now, we would know. How would we know, if they didn't want us to know? We're talking about technology far superior to our own, right?

It is indeed conceivable that invisible aliens are among us, but as the scenario is (by its very nature) unsupported by evidence and pretty much unfalsifiable, it's probably best filed under "fruitless speculation", and for this reason most people take the default position to be that it isn't happening.

As I understand it, science isn't much concerned with the unknowable.

Paul Beardsley
2012-Nov-28, 05:40 PM
That applies only if the aliens never took the evolutionary leap beyond their original biological form. Given the progress that has been made in my own lifetime with computers, I have little doubt (unless mankind suffers a major setback) that will we create cognitive "machines". These will eventually be beings of greater intellectual stature than ourselves without our biological limitations. I'm not saying we are anywhere near that yet, but we will get there, perhaps within the next century even.

Human brains work quite differently from computers however there is no neurological process in the brain that is impossible to mimic with electronics. People right now are studying the structure of the brain and attempting to create hardware that mimics it. One difference will be that instead of a synapse operating with a 1 millisecond delay there will be synapses reacting with < 1 nanosecond delay (one million times faster). What happens then is anybody's guess. My main point is that our thinking is anthropomorphic when we assume that aliens would arrive as bio-chemical life forms.

You're coming up with science fictional scenarios - possibly even good ones, possibly even ones that will turn out to be true - but they are nevertheless nothing more than speculation.

Surely it's anthropomorphic thinking to suppose the aliens will follow the same path of us with electronics?

And what's so significant about faster synapses? Surely that just means the post-humans will see the world slow down. And given that electronics are more durable, is it even necessary for the synapses to be faster? A 10 millisecond delay might be handy when you're waiting for your favourite TV programme to come on.

TooMany
2012-Nov-28, 06:14 PM
You're coming up with science fictional scenarios - possibly even good ones, possibly even ones that will turn out to be true - but they are nevertheless nothing more than speculation.


So? If you're not interested in speculation, why are you interested in this thread? Do you feel that speculation has no place in science?



Surely it's anthropomorphic thinking to suppose the aliens will follow the same path of us with electronics?


Perhaps. Maybe they will just click and whir for a short while and then decide to turn themselves off? (Not likely.) Is it unreasonable to conjecture that we will strive to create artificial intelligence that behaves somewhat as we do (in our own image so to speak)? (I'm not going so far as to propose that these new beings will look like Data.)



And what's so significant about faster synapses?


Obsolesce of biological intelligence.



Surely that just means the post-humans will see the world slow down. And given that electronics are more durable, is it even necessary for the synapses to be faster? A 10 millisecond delay might be handy when you're waiting for your favourite TV programme to come on.

But are you overlooking the fact that the machines can place themselves in a pause state or a state of partial operation when they are "bored". That makes interstellar travel not only less painful but also much more practical. We don't have to imagine that a 20,000 year trip will require the housing and nurturing of 100 generations of biological beings. For the artificial being the trip may be quite short. No reason to sit around clicking and whirring for 20 centuries while waiting to arrive at the locale of interest.

Paul Beardsley
2012-Nov-28, 06:24 PM
So? If you're not interested in speculation, why are you interested in this thread?

Where did I say I was not interested in speculation?


Do you feel that speculation has no place in science?

I think it has a valuable place, but I get concerned when it appears to be presented as a conclusion.

TooMany
2012-Nov-28, 08:27 PM
Where did I say I was not interested in speculation?



I think it has a valuable place, but I get concerned when it appears to be presented as a conclusion.

But I'm not drawing solid conclusions, I'm making possible/probable (not known) conclusions. What is your concern? Is there some potential damage? We are talking about things of which we have no direct knowledge. That requires us to extrapolate using the knowledge that we do have. This is a worthwhile endeavor (even though speculative) because we can search the space of possibilities based on what we know to make guesses about what is possible and even probable. When can use those guesses to help us find what interests us, in this case aliens. There is nothing wrong with thought experiments. Even though they are not based on direct observation, they are (famously) useful.

I brought up some of these "science fiction" ideas to see what ideas others have and to see what useful conjectures we might make or exclude using our collective intelligence.

Someone pointed to an article about SETI which complains that the type of search being done was not the best. It is helpful to conjecture about the aliens as part of the effort to actually discover them. E.g., perhaps expecting radio transmissions is akin to expecting smoke signals. That's not to say it isn't a good idea to look for radio transmissions, but just that we should speculate using what we know and what we can imagine to assess the probable value of our search methods and innovate new ones.

R.A.F.
2012-Nov-28, 10:13 PM
But I'm not drawing solid conclusions, I'm making possible/probable (not known) conclusions. What is your concern?

The concern is that without sufficient data, you shouldn't be drawing ANY conclusions...and that you are "substituting" speculation for actual evidence.

We will, or we will not know these things given enough time and evidence....however if you try to "rush" things along by massive speculation, you will end up arriving at the wrong conclusion.

R.A.F.
2012-Nov-28, 10:24 PM
Well, I have no idea about the "as we speak" speak part.

As we speak = at this very moment.

I was asking about current sightings. Do you think that evidence indcates that aliens are visiting Earth right now.




All I'm doing is extrapolating to suggest the possibility/probability of visitation at some time or other.

But is it actually "probable/possible"?....or do you just wish it was?



Here is yet another possible/probable speculation. It appears that terrestrial (rocky) planets like earth are found in other systems. I will speculate with some confidence that the mineral quartz exists on the surface of most of these planets. Now this is also a question that will probably not be answered in our lifetimes; do you deny that it is probable?

Are you seriously comparing ET life, to a rock?...do you really, sincerely think that a "fair" analogy?






I don't see why this would be as just as probable at all. Why would there at most one or exactly one civilization per galaxy

Because that's the way I arbitrarily decided it. It no different than any other unevidenced speculation, yet you "find fault" wth it?

What makes your speculation any more special than mine?



What argument do you propose for that?

Why just as you have, I'm making NO ARGUMENT....I'm just speculating.

R.A.F.
2012-Nov-28, 10:30 PM
...there is no neurological process in the brain that is impossible to mimic with electronics.

Right....

TooMany
2012-Nov-28, 10:40 PM
The concern is that without sufficient data, you shouldn't be drawing ANY conclusions...and that you are "substituting" speculation for actual evidence.

We will, or we will not know these things given enough time and evidence....however if you try to "rush" things along by massive speculation, you will end up arriving at the wrong conclusion.

I guess then you don't buy that there is any benefit to giving the subject some thought without additional evidence? We have evidence of life on earth. of organic molecules in space, of evolutionary processes, of the existence of other planetary systems, of our own technology moving toward space exploration and artificial intelligence, but we should not make use of that evidence to formulate ideas about what might be because we could be wrong?

Suppose we do end up arriving at some wrong conclusion. How is that more harmful than not even trying to draw possible conclusions from what evidence we have?

Just to be sure that you don't misunderstand me, I'm not suggesting that there is unique conclusion which we should strive to reach. Rather that we should examine the space of possibilities and see what conclusions are possible and/or probable.

TooMany
2012-Nov-29, 12:03 AM
As we speak = at this very moment.

I was asking about current sightings. Do you think that evidence indcates that aliens are visiting Earth right now.


I have not seen anything convincing. In fact, as I already stated, it's likely that if there are aliens visiting earth, they do not wish to be discovered. This is one reason that I am rather skeptical of "sightings". If the conjectured advanced aliens wanted to be known to us, then they could have introduced themselves. I conclude that if they do exist and visit us, they do not want to be detected. I would allow that a sufficiently advanced technology could do a respectable job of staying hidden. Given that theory, a sighting would indicate a failure of their advanced technology or some sort of accident. Presuming that the technology is far superior, multiple failures resulting in sightings seems unlikely.



But is it actually "probable/possible"?....or do you just wish it was?


What do you mean by "actually"? Do you want to provide an argument why aliens do not exist or cannot travel between the stars? Perhaps an argument that life is extremely rare, or that intelligent life is all but impossible or that technology cannot be developed sufficiently beyond what we already have to make interstellar travel possible?

There may be an element of wish here: Wouldn't it be really interesting to find another intelligent life form? On the other hand we need to be careful what we wish for. In our own planet's history, contact with aliens from faraway continents possessing superior technology hasn't usually worked out very well for those who were visited. I think Stephen Hawking seriously suggested that we should be careful not to advertise our existence lest earth become prey.

However I might feel about the possibility of alien life or visitation (positive or negative), I can look at the facts we have and extrapolate some possibilities. You seem to have marked disdain for such extrapolation.



Are you seriously comparing ET life, to a rock?...do you really, sincerely think that a "fair" analogy?


Well it's only unfair if we take for granted that life is far less likely to form on a planet (even under favorable conditions) than a certain type of rock.

I said, "Why would there be at most one or exactly one civilization per galaxy"?



Because that's the way I arbitrarily decided it. It no different than any other unevidenced speculation, yet you "find fault" wth it?

What makes your speculation any more special than mine?


You offered no justification for your speculation. If I haven't made that part of my speculation clear, then I'll spell it out a little. There are 100 billion stellar systems in our galaxy. It is now believed that perhaps 1/2 have planets. Suppose that only 1 in 1,000 systems has a nice earth-like planet and suitable star. That's 100,000,000 opportunities for alien intelligence to form (via a path that we already know is possible). And so on...

That's what makes the speculation that aliens exist much more special than the speculation that there are none.



Why just as you have, I'm making NO ARGUMENT....I'm just speculating.

Everything I've speculated about I've based on things we already know and plausible consequences. If I missed some explanation then I'll be pleased to provide it.

TooMany
2012-Nov-29, 12:09 AM
I said: "...there is no neurological process in the brain that is impossible to mimic with electronics."


Right....

I can't tell; is that agreement or sarcastic disagreement?

Jens
2012-Nov-29, 12:25 AM
Imagine a scientist in the eighteen century. At that time they knew the distance of the moon. Don't you think they probably would have concurred that "the distance involved is great that I doubt it is realistic" to travel to the moon? At that time I wonder whether anyone had even thought about the possibility of building a big enough rocket to go to the moon.

That's certainly true, but you can't simply assume that anything is possible just because people have been wrong in the past about what is possible. I'm not saying there is anything wrong with you speculating that we might somehow find a way to achieve interstellar travel. I see no evidence for it now, and it seems technologically impractical, so I am just concluding that it probably hasn't been done. But I emphasize again that I'm not saying you're wrong for doubting my position.


What is the foundation for "they clearly aren't [visiting earth] now"? For 3 "there is no evidence for it", I'd simply repeat that absence of evidence is not firm evidence of absence. Your assumption seems to be that if they did visit us here and now, we would know. How would we know, if they didn't want us to know? We're talking about technology far superior to our own, right?

Sure, absence of evidence is not evidence of absence. But I'm not claiming evidence of absence. I'm just appealing to Ockham's razor. If I see no evidence of something, and there is no reason to think it is likely, then I conclude it probably isn't true.

R.A.F.
2012-Nov-29, 12:44 AM
In fact, as I already stated, it's likely that if there are aliens visiting earth, they do not wish to be discovered. This is one reason that I am rather skeptical of "sightings". If the conjectured advanced aliens wanted to be known to us, then they could have introduced themselves. I conclude that if they do exist and visit us, they do not want to be detected. I would allow that a sufficiently advanced technology could do a respectable job of staying hidden. Given that theory, a sighting would indicate a failure of their advanced technology or some sort of accident. Presuming that the technology is far superior, multiple failures resulting in sightings seems unlikely.

So you agree that the evidence for current alien visitation is not credible....good...



Do you want to provide an argument why aliens do not exist or cannot travel between the stars?

The argument is....they are not here Given the age of the Universe, I would expect a large portion of this Galaxy to be colonized by now....that is, if life is abundant in the Universe.



Perhaps an argument that life is extremely rare, or that intelligent life is all but impossible or that technology cannot be developed sufficiently beyond what we already have to make interstellar travel possible?

I hope this is the last time I have to say this....STOP PUTTING WORDS IN MY MOUTH.

Address statements I actually make, not statements you 'think" I am making.



There may be an element of wish here...

Ya think? Who in this whole world wouldn't be thrilled to have the answer to the ultimate question...is there life "out there".

Personally, I can wait until there is conclusive evidence for life elsewhere...



However I might feel about the possibility of alien life or visitation (positive or negative), I can look at the facts we have and extrapolate some possibilities. You seem to have marked disdain for such extrapolation.

I have a "marked distain" for speculation masquerading as "fact".




You offered no justification for your speculation.

Yes....you finally get the "point".

R.A.F.
2012-Nov-29, 12:51 AM
...absence of evidence is not evidence of absence.

I am so friggin' tired of hearing this mantra as if it somehow explains the absence of any credible evidence for ET....it does not...absence of evidence also means that the idea being proposed isn't a very good idea...

We will learn what is the truth, and what is baseless speculation.

What we won't do, is learn anything about the Universe, by disregarding the importance of evidence.

R.A.F.
2012-Nov-29, 12:54 AM
I said: "...there is no neurological process in the brain that is impossible to mimic with electronics."



I can't tell; is that agreement or sarcastic disagreement?


Lets just say I disagree...:D

Paul Wally
2012-Nov-29, 01:02 AM
You offered no justification for your speculation. If I haven't made that part of my speculation clear, then I'll spell it out a little. There are 100 billion stellar systems in our galaxy. It is now believed that perhaps 1/2 have planets. Suppose that only 1 in 1,000 systems has a nice earth-like planet and suitable star. That's 100,000,000 opportunities for alien intelligence to form (via a path that we already know is possible). And so on...


What we can do now is to calculate an average distance between civilizations, if 1 in 1000 systems have a civilization. That should give us some idea of the distance the nearest alien civs would have to travel to come visit us.

Selfsim
2012-Nov-29, 02:02 AM
What we can do now is to calculate an average distance between civilizations, if 1 in 1000 systems have a civilization. That should give us some idea of the distance the nearest alien civs would have to travel to come visit us.Which would also be a totally meaningless statistic, if it is based on the similarly meaningless "100,000,000 opportunities for alien intelligence to form" statement.

There is no established, evidence-based relationship between the presence of life on one planet called 'Earth', and its emergence … (… 100,000,000??, 1010??,1020??,1050??, etc - it makes zilch difference).

Construction of a phenomenological hypothesis, is similarly thwarted by a lack of non-Earth based data.

It doesn't matter how many "nice earth-like planet(s)" there are out there … until either of these relationships is established in evidence, none of this 'idea' is constrained, other than by opinion and belief.

I recommend that a heavy electron tax be applied to such speculations, as distortion of the perception of science and mathematics, is what results. Multiply this by the numbers of speculations dressed up to look like science, (like this one is), and an encyclopedia of sci-fi, is all that results.

Its a 'racket', I tell ya!

TooMany
2012-Nov-29, 02:28 AM
So you agree that the evidence for current alien visitation is not credible....good...


Exactly.



The argument is....they are not here Given the age of the Universe, I would expect a large portion of this Galaxy to be colonized by now....that is, if life is abundant in the Universe.


It seems that you are assuming that aliens who reach the intellectual and technical maturity necessary for interstellar travel would want to colonize the Galaxy. I think that's a questionable assumption. If a particular alien race were in desperate need of something that they could not obtain in their system or if they were concerned that their star was unstable, then I suppose they would attempt to colonize one or more nearby systems. Other than that, what need would this superior intelligence and technology have for running around the Galaxy colonizing biologically favorable planets, particularly if they have already made a transition away from biochemical life?



I hope this is the last time I have to say this....STOP PUTTING WORDS IN MY MOUTH.

Address statements I actually make, not statements you 'think" I am making.


Sorry, I truly don't mean to put words in your mouth. I was trying to guess what your thinking was since you seem to so strongly disagree with the notion that aliens exist and may have visited earth. You didn't say why that I can recall.



Ya think? Who in this whole world wouldn't be thrilled to have the answer to the ultimate question...is there life "out there".

Personally, I can wait until there is conclusive evidence for life elsewhere...


Well, we haven't much choice but to wait to actually know. But there's nothing illegal, immoral or unscientific about considering the possibility. That is exactly how the "Fermi paradox" came to be. A respected scientist, having lunch with some friends, was apparently seriously considering the high probability of intelligent alien life but noted that the idea appears to be in conflict with the fact that we haven't met them. I have no idea where Fermi's thinking went on from there.

Myself, I would not easily give up the idea that alien life should be common (especially over the age of the Galaxy). So one possible answer to Fermi's paradox is that yes the aliens do exist and do travel among the stars but have no desire to reveal themselves to us or alter our course of history. There are other possibilities as well.



I have a "marked distain" for speculation masquerading as "fact".


Good , but who is claiming that the speculation is a fact?



Yes....you finally get the "point".

No, I'm sorry but I don't get the point. Is it that speculation based on extrapolation from knowledge is no different from arbitrary speculation absent of justification?

theNater
2012-Nov-29, 02:43 AM
All right, going back a few posts to handle a few claims that really need to be double checked.

First I suggest that life (organic life as we know it) emerges pretty much where ever the opportunity exists for it to arise.
Unknown. We only have one example; the only conclusion we can draw from it is that organic life as we know it can arise. We certainly do not know that it is inevitable in favorable conditions, as you suggest.

We now know that planetary systems are quite common and that occasionally one will contain a planet suitable to create and support life.
Occasional implies a non-negligible frequency. Many people would not apply it to something happening less frequently than 1% of the time, and for all we know suitable planets are one in a billion.

We also know that biological evolution leads to increasingly complex nervous systems which eventually results in a species like our own.
Incorrect. As with the emergence of life, we can only conclude that it is possible, not that it is inevitable.

We as a species are already taking our first baby steps beyond our planet and there is every indication that we will pursue interstellar travel despite the patience required to get something back from the endeavor.
Should we survive essentially as we are indefinitely, I agree. However, extinction level events are still possible, and it is possible that evolution or our own actions will change us in some way as to make us cease pursuit of interstellar travel.

At the same time we are beginning to create artificial intelligence which because of various advantages over biological systems will far exceed our abilities as organics beings.
Unknown. It is not certain that artificial intelligence will ever be realized. Also, it is possible that such intelligences will require physical housings with frailties comparable to(though certainly not identical to) those of biological bodies.

In other words we can foresee a transformation of biological intelligence into a new non-biological from of life.
Indeed we can.

I further suggest that this non-biological life is for practical purposes immortal (although not necessarily fully so) and possesses the patience needed for interstellar travel.
Unknown. Without knowing more about the construction of such life, we cannot make any reasonable conclusions about its capabilities and inclinations.

Moreover this non-biological intelligence is perfectly capable of mass production of cognitive machines capable of exploring the galaxy.
Unknown. Without knowing the resource requirements for such cognitive machines, we cannot conclude that their mass production is possible.

The galaxy is far older than the sun and earth and over that time the evolution of such intelligent life capable of interstellar travel has undoubtedly occurred many times.
This is only undoubtable if all of the maybes above are the certainties you suggest they are.

So we should expect that the galaxy has already been explored even if for no other purpose than to take a census.
It is uncertain that alien life, should such exist, will desire to perform a thorough census. We do not know that their motivations and procedures will resemble ours in any way.

There are many other possible explanations of the Fermi paradox as well that don't require life as we know on earth to be an extreme rarity. I have just picked one as an example. Regardless of our failure to find aliens, what we already know about the universe is pretty good indication that they should exist. The solution to the Fermi paradox is extremely unlikely to be that we are alone, so I think it is worthwhile to consider other possibilities.

Absence of evidence is not dependable evidence of absence.
Lacking further information, we cannot conclude how likely or unlikely it is that we are alone. However, the point behind Occam's Razor is that while absence of evidence isn't evidence of absence, there are so many things we have no evidence for that it is safest to assume none of them exist. Assuming they all exist is impractical, and selecting specific ones to assume extant and others to assume not is just begging to show off our biases.

R.A.F.
2012-Nov-29, 04:06 AM
Sorry, I truly don't mean to put words in your mouth. I was trying to guess what your thinking was since you seem to so strongly disagree with the notion that aliens exist and may have visited earth.

I don't "disagree" with anything...I simply think that if aliens exist, speculating isn't going to prove one way or the other what the correct answer is.

Only actual, credible, testable evidence can do that.


...and since I tire of "explaining" my posts to you, I'm "out" of this thread...respond if you like, but I won't be reading it.

TooMany
2012-Nov-29, 03:50 PM
What we can do now is to calculate an average distance between civilizations, if 1 in 1000 systems have a civilization. That should give us some idea of the distance the nearest alien civs would have to travel to come visit us.

True, can you come up with a figure?

TooMany
2012-Nov-29, 06:19 PM
All right, going back a few posts to handle a few claims that really need to be double checked.

Unknown. We only have one example; the only conclusion we can draw from it is that organic life as we know it can arise. We certainly do not know that it is inevitable in favorable conditions, as you suggest.


I'm not saying that any of this is a fact. While it is logically correct that we don't know that life is very likely or inevitable under favorable conditions, consider the converse assumption: Even with favorable conditions, life very rarely develops. In order to support that speculation you need to postulate something like this: Although we can with some confidence infer that organics will exist in other systems and although we know that primitive biological molecules form spontaneously in asteroids, in space and in laboratory experiments, the chances of that leading to life are extremely slim.

Why would that be? Perhaps because it's just too big a gap from some organic molecules to something that can reproduce and inherit? We lack knowledge of the steps to get from organic molecules to a reproductive structure. Does that leave us bewildered about how it could ever happen and with the conclusion that it is very rare? We may learn more about possible paths to life in the near future and perhaps that could unseat this idea that life is a very unlikely accident.

We don't know exactly when life began on earth. It certainly didn't start with something as large and complex as bacteria. It's very difficult to trace it back to an origin. However, some biologists believe that life started shortly (in geological terms) after conditions on the surface were non-sterilizing. Wiki:
Abiogenesis likely occurred between 3.9 and 3.5 billion years ago, in the Eoarchean era (i.e. the time after the Hadean era in which the Earth was essentially molten). It's even possible that it started multiple times only to be wiped out by sterilizing asteroid impacts.

We do not know with certainty, that is true, but why should we believe that there is something very special or accidental about life forming on earth?



Occasional implies a non-negligible frequency. Many people would not apply it to something happening less frequently than 1% of the time, and for all we know suitable planets are one in a billion.


That doesn't jibe with the current evidence that are about two planets per star (on average). It's true that we don't yet know the precise probability of terrestrial planets in the habitable zone but one in a billion?



Incorrect. As with the emergence of life, we can only conclude that it is possible, not that it is inevitable.


100% percent certainty is required for an absolute conclusion, that is true. So? That doesn't mean we cannot speculate. If life is not inevitable under proper conditions, we also need an explanation for that.



Unknown. It is not certain that artificial intelligence will ever be realized. Also, it is possible that such intelligences will require physical housings with frailties comparable to(though certainly not identical to) those of biological bodies.


Not absolutely certain, true. However, what do barrier do you foresee that could prevent artificial intelligence from becoming a reality?

Concerning the frailty, that is contradicted by the mechanisms that we already have. For example we send machines to explore Mars. While they are not yet autonomous, there are clear advantages of working toward that goal. The cost of putting on man on Mars dwarfs the cost of a mechanism exactly because of the frailty and required support structure for exploration by biological beings. No human could survive the conditions that Curiosity easily endures without a large and complex support system. (IMO the whole man-in-space idea is impractical in comparison with the alternatives that are in development.)



Lacking further information, we cannot conclude how likely or unlikely it is that we are alone. However, the point behind Occam's Razor is that while absence of evidence isn't evidence of absence, there are so many things we have no evidence for that it is safest to assume none of them exist. Assuming they all exist is impractical, and selecting specific ones to assume extant and others to assume not is just begging to show off our biases.

I don't see where safety is involved. What danger do we put ourselves in by speculating? Imagine a general in a war. He does not know exactly what the enemy will do next, so he thinks about it deeply and speculates in order to gain an advantage. Stephen Hawking apparently feels that we should be concerned about keeping our existence hidden and thus avoid possible alien exploitation. He is speculating but it's worthy of consideration (IMO).

TooMany
2012-Nov-29, 06:47 PM
Construction of a phenomenological hypothesis, is similarly thwarted by a lack of non-Earth based data.


That's simply not true. We do not need further evidence to construct an hypothesis. Scientists in fact have already constructed this hypothesis (that life will develop elsewhere if conditions similar earth's are present.) That hypothesis is the driving force behind our search for exoplanets similar to our own. We are spending considerable money on this endeavor (over 1 billion for Mars Curiosity) and there are scientists who are basing their careers on this hypothesis.



It doesn't matter how many "nice earth-like planet(s)" there are out there … until either of these relationships is established in evidence, none of this 'idea' is constrained, other than by opinion and belief.


Then I guess you are dead set against any venture based on this idea that is only "opinion and belief"?



I recommend that a heavy electron tax be applied to such speculations, as distortion of the perception of science and mathematics, is what results. Multiply this by the numbers of speculations dressed up to look like science, (like this one is), and an encyclopedia of sci-fi, is all that results.

Its a 'racket', I tell ya!

Fortunately we have plenty of scientists who dare to speculate and are not subject to your proposed tax. We would still be living in trees in the absence of freedom to speculate.

Paul Wally
2012-Nov-29, 07:35 PM
True, can you come up with a figure?

Some googling revealed that the first TV broadcasts should have reached about a thousand stars by now. So what is that, about 75 years ago x 2 is 150 light years. It's of course not completely correct but it gives a rough idea.

NoChoice
2012-Nov-29, 10:44 PM
Lacking further information, we cannot conclude how likely or unlikely it is that we are alone. However, the point behind Occam's Razor is that while absence of evidence isn't evidence of absence, there are so many things we have no evidence for that it is safest to assume none of them exist. Assuming they all exist is impractical, and selecting specific ones to assume extant and others to assume not is just begging to show off our biases.

I agree with everything in your post, except the last 3 sentences I'm quoting.
Unknown is unknown. End of story. No further qualification needed.

Why then assume anything as you do in the last 3 sentences?
When a scientist is asked "Do green unicorns exist?", the only possible answer (s)he can give as a representative of current scientific knowledge (and not just uttering personal opinions) is "We don't know."
No other answer should be given.

Why should science assume anything about "green unicorns"? It must neither assume they exist nor they don't exist.

TooMany
2012-Nov-29, 11:18 PM
Some googling revealed that the first TV broadcasts should have reached about a thousand stars by now. So what is that, about 75 years ago x 2 is 150 light years. It's of course not completely correct but it gives a rough idea.

I hope that doesn't mean someone's on the way to start harvesting us for food. Seriously, those sorts of speculations you see in some sci-fi are quite easy to dismiss. Imagine, we've got a civilization capable of traveling among the stars but they have a food shortage problem that they cannot solve short of harvesting food from earth? This is one reason that it's interesting to think about these things, even though we don't know anything for sure. Not knowing doesn't prevent us from making a realistic assessment of the possibilities so we can stop worrying about being eaten by aliens.

Paul Wally
2012-Nov-30, 12:09 AM
I hope that doesn't mean someone's on the way to start harvesting us for food. Seriously, those sorts of speculations you see in some sci-fi are quite easy to dismiss. Imagine, we've got a civilization capable of traveling among the stars but they have a food shortage problem that they cannot solve short of harvesting food from earth? This is one reason that it's interesting to think about these things, even though we don't know anything for sure. Not knowing doesn't prevent us from making a realistic assessment of the possibilities so we can stop worrying about being eaten by aliens.

If I have to guess, I'll say that 1 in 1000 is probably a best case scenario as far as intelligent space faring civilizations are concerned. But let's take the 150 light year distance. How long will it take humans to get that far? A thousand, a million or billion years from now? Perhaps if we could figure out how long it would take us, that would give us some idea of how long it would take other civilizations.

whimsyfree
2012-Nov-30, 01:37 AM
When a scientist is asked "Do green unicorns exist?", the only possible answer (s)he can give as a representative of current scientific knowledge (and not just uttering personal opinions) is "We don't know."
No other answer should be given.


Unicorns are horses with horns and are referenced, AFAIK, only by legends, ballads and other sources generally regarded as fictional. So if by "unicorn" one means a creature from one of these fictions then the question is already answered. It doesn't exist in the same way that Aslan from Narnia doesn't exist. Maybe somewhere on a distant planet there is an animal that looks like a horse with one horn, but it's not the creature mediaeval writers wrote about.


Why should science assume anything about "green unicorns"? It must neither assume they exist nor they don't exist.

The problem with that is that science is a series of activities, not just a collection of statements about the state of scientific evidence. When I'm planning my next field trip should I consider a search for green unicorns or not? "We don't know" is not a useful answer in that context. The decision is made by applying reasoning heuristics (such as Occam's razor) and our experience with which sorts of hypotheses tend to provide fruitful research activities (such as ones about peptide folding and planetary motions) and which sorts don't (such as searches for fairy-tale creatures). We would probably consult the list of areas for which funding was available fairly closely too.

NoChoice
2012-Nov-30, 03:08 AM
The problem with that is that science is a series of activities, not just a collection of statements about the state of scientific evidence. When I'm planning my next field trip should I consider a search for green unicorns or not? "We don't know" is not a useful answer in that context. The decision is made by applying reasoning heuristics (such as Occam's razor) and our experience with which sorts of hypotheses tend to provide fruitful research activities (such as ones about peptide folding and planetary motions) and which sorts don't (such as searches for fairy-tale creatures). We would probably consult the list of areas for which funding was available fairly closely too.

I would agree with you. But you are talking about hypotheses. The OP, however, was talking about a definitive statement of knowledge.
The "expert" in the OP who stated that aliens don't exist has either no understanding of how science works or is dishonest. Such statements should not be made by any scientist!

When you plan a field trip and you need to chose a hypothesis to operate under I would certainly also assume that you don't need to prepare for green unicorns. Or to make the example more drastic: When you plan a field trip you wouldn't ask for a military unit to accompany you in case there are evil aliens hiding in the bushes.
That's where Occam's razor comes in. Occam's razor is NOT a means to gain scientific knowledge. It is a helpful rule to choose between competing hypotheses. But it should also be clear that it is not a rule set in stone. There are certainly cases where among competing hypotheses the one with more assumptions than another one may very well turn out to be the correct one.
It is a good rule but not a fixed one.

Jens
2012-Nov-30, 04:37 AM
When a scientist is asked "Do green unicorns exist?", the only possible answer (s)he can give as a representative of current scientific knowledge (and not just uttering personal opinions) is "We don't know."
No other answer should be given.


I really don't agree. It may be true that we don't know, but I think a better answer is, "We have no reason to believe they exist."

Otherwise, if the world were organized the way you suggest, we would never be able to state anything.

Are you going to the party? I plan to, if I happen to still be alive by next Friday, which is uncertain. So I don't know.

Is this beef? Well, my memory tells me that I read "beef" on the label, but I could be incorrectly remembering. And even then, the label could be wrong. So frankly, I don't know.

Technically those are true statements, but I don't think they're particularly helpful.

NoChoice
2012-Nov-30, 06:18 AM
I really don't agree. It may be true that we don't know, but I think a better answer is, "We have no reason to believe they exist."

Otherwise, if the world were organized the way you suggest, we would never be able to state anything.

Are you going to the party? I plan to, if I happen to still be alive by next Friday, which is uncertain. So I don't know.

Is this beef? Well, my memory tells me that I read "beef" on the label, but I could be incorrectly remembering. And even then, the label could be wrong. So frankly, I don't know.

Technically those are true statements, but I don't think they're particularly helpful.

You are comparing apples with oranges.

The "normal" mode of human communication is filled with unspoken assumptions, logical flaws, etc.

The scientific mode of communication is (or is supposed to be) a very different animal.
Utilizing that mode you are supposed to list and support any and all assumptions that go into a conclusion, the exact steps how you arrived at the conclusion, etc.
The scientific mode of communication and the scientific method were designed to avoid or otherwise deal with the shortcomings of the "normal" mode of human communication and reasoning.

I therefore hold the scientific mode of communication to much higher standards - as it should be.
That is why I always make it clear what I am talking about by qualifying it with something like "as a representative of current scientific knowledge (and not just uttering personal opinions)" to make it very clear I am talking about the scientific mode of communication.

I don't like statements like "We have no reason to believe THING exist" because they open up the communication to personal bias and it usually creeps right in.
It is ambivalent. The statement "We don't know whether or not THING exist." is pretty concise and doesn't leave much room for interpretation.

Example:
"We have no reason to believe ghosts exist".
A very tricky statement. Others might say: "Well, I think we do because so many people are seeing them!"
I don't want to start a discussion about ghosts! This is just an example about the ambivalence you can introduce with the type of statement you seem to favor.

On the other hand, the statement "We don't know whether or not ghosts exist." is clear, unbiased and leaves little room for interpretation.

ASTRO BOY
2012-Nov-30, 06:29 AM
but I think a better answer is, "We have no reason to believe they exist."
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""


We have plenty of reasons to believe they could exist.......The ingrediants of life being everywhere and the sheer weight of numbers multiplying the chances of the ingrediants assembling into life forms.

Selfsim
2012-Nov-30, 08:17 AM
I therefore hold the scientific mode of communication to much higher standards - as it should be.
That is why I always make it clear what I am talking about by qualifying it with something like "as a representative of current scientific knowledge (and not just uttering personal opinions)" to make it very clear I am talking about the scientific mode of communication.Good point .. and yet others seem to be unable to distinguish or articulate their own opinions from arguments which they deem to be plausible/probable, whilst appearing to be following a scientific process ...
This would seem to be especially so, when their initial posits have no basis in physical fact ...

I could make another (speculative but nevertheless plausible) argument that aliens do exist and that in all probability they have visited earth. First I suggest that life (organic life as we know it) emerges pretty much where ever the opportunity exists for it to arise. We now know that planetary systems are quite common and that occasionally one will contain a planet suitable to create and support life. We also know that biological evolution leads to increasingly complex nervous systems which eventually results in a species like our own ...
Fascinating ...

theNater
2012-Nov-30, 04:30 PM
I'm not saying that any of this is a fact. While it is logically correct that we don't know that life is very likely or inevitable under favorable conditions, consider the converse assumption: Even with favorable conditions, life very rarely develops. In order to support that speculation you need to postulate something like this: Although we can with some confidence infer that organics will exist in other systems and although we know that primitive biological molecules form spontaneously in asteroids, in space and in laboratory experiments, the chances of that leading to life are extremely slim.

Why would that be? Perhaps because it's just too big a gap from some organic molecules to something that can reproduce and inherit? We lack knowledge of the steps to get from organic molecules to a reproductive structure. Does that leave us bewildered about how it could ever happen and with the conclusion that it is very rare? We may learn more about possible paths to life in the near future and perhaps that could unseat this idea that life is a very unlikely accident.

We don't know exactly when life began on earth. It certainly didn't start with something as large and complex as bacteria. It's very difficult to trace it back to an origin. However, some biologists believe that life started shortly (in geological terms) after conditions on the surface were non-sterilizing. Wiki: It's even possible that it started multiple times only to be wiped out by sterilizing asteroid impacts.

We do not know with certainty, that is true, but why should we believe that there is something very special or accidental about life forming on earth?
There are stages between almost always and almost never. Suppose life emerges on 50% of the worlds where the opportunity exists. That doesn't make Earth very special, but it does heavily influence the overall calculation.

That doesn't jibe with the current evidence that are about two planets per star (on average). It's true that we don't yet know the precise probability of terrestrial planets in the habitable zone but one in a billion?
Possibly. We really don't know, and assuming it is high enough to be called occasional merely because doing so supports the conclusion we want is pretty much the definition of bias.

100% percent certainty is required for an absolute conclusion, that is true. So? That doesn't mean we cannot speculate. If life is not inevitable under proper conditions, we also need an explanation for that.
Here we weren't talking about life, but about intelligence. Evolution is a highly random process; it is certainly not clear that it always leads to increasingly complex nervous systems, or even nervous systems at all. There are many forms of life on Earth with no nervous system, and they've been evolving as long as anything else on Earth.

Not absolutely certain, true. However, what do barrier do you foresee that could prevent artificial intelligence from becoming a reality?
I don't foresee such a barrier, but to be intellectually honest, we must permit for the possibility that one exists.

Concerning the frailty, that is contradicted by the mechanisms that we already have. For example we send machines to explore Mars. While they are not yet autonomous, there are clear advantages of working toward that goal. The cost of putting on man on Mars dwarfs the cost of a mechanism exactly because of the frailty and required support structure for exploration by biological beings. No human could survive the conditions that Curiosity easily endures without a large and complex support system. (IMO the whole man-in-space idea is impractical in comparison with the alternatives that are in development.)
It is highly likely that an intelligent mechanism will need to be more complex than the machines we are currently using. Additional complexities mean additional potential failure points. In a speculative discussion, we can't simply rule out the possibility that once a thing is complex enough to be intelligent, it is fragile enough to require a large and complex support system.

I don't see where safety is involved. What danger do we put ourselves in by speculating? Imagine a general in a war. He does not know exactly what the enemy will do next, so he thinks about it deeply and speculates in order to gain an advantage. Stephen Hawking apparently feels that we should be concerned about keeping our existence hidden and thus avoid possible alien exploitation. He is speculating but it's worthy of consideration (IMO).
The value of speculation in science, as in strategy, is to assist in allocation of resources. Good generals base their primary plans on what the enemy is most likely to do, rather than all the things the enemy may possibly do(backup plans may be prepared for possible situations, of course). Similarly, someone going hiking in North America should prepare for bears, rather than komodo dragons or green unicorns.

With Stephen Hawking's speculation in particular, the danger is that we refrain from performing some sort of scientific investigation out of fear that it will reveal our existence. How much high-profile investigation we do should be based on how likely it is that there is alien life which will detect it, rather than on whether or not alien life might be able to detect it.

TooMany
2012-Nov-30, 08:27 PM
We really don't know, and assuming it is high enough to be called occasional merely because doing so supports the conclusion we want is pretty much the definition of bias.


I don't think bias has anything to do with this discussion.



Here we weren't talking about life, but about intelligence. Evolution is a highly random process; it is certainly not clear that it always leads to increasingly complex nervous systems, or even nervous systems at all. There are many forms of life on Earth with no nervous system, and they've been evolving as long as anything else on Earth.


Evolution is not a random process in this sense, it tends toward whatever makes a species more successful. While variations may be random, selection is not. Yes, there are plenty of organisms with no nervous systems (all are microscopic or plants). There is plenty of space in ecosystems for all kinds of things. Nevertheless nervous systems increase in complexity for a very obvious reason: it presents a survival advantage. The idea that nervous systems are just happenstance ignores the theory of evolution.

If you want some evidence that diverse species independently develop complex nervous systems, look at octopi. Those creatures are pretty smart and they are not even vertebrates. In fact the structure of an octopus eye is quite similar to a human eye, but there is nothing in common except that such eyes work.



I don't foresee such a barrier, but to be intellectually honest, we must permit for the possibility that one exists.


Yes and we must also permit that all kinds of strange things could happen, but what's the point in focusing on that which is unlikely?



It is highly likely that an intelligent mechanism will need to be more complex than the machines we are currently using. Additional complexities mean additional potential failure points. In a speculative discussion, we can't simply rule out the possibility that once a thing is complex enough to be intelligent, it is fragile enough to require a large and complex support system.


I can't agree with the fragile conclusion. The size of a modern logic gate is about 90nm. The size of a small neuron is about 4,000nm. And yet the logic gate is much more robust than the neuron. It can take much bigger temperature differences, it can work in a vacuum or in air. Yes, a large support structure is required to create an artificial intelligence, but after that all it needs is some electrical power and some reasonable temperature control and spare parts to survive. Support for a biological intelligence is far more complex.



The value of speculation in science, as in strategy, is to assist in allocation of resources. Good generals base their primary plans on what the enemy is most likely to do, rather than all the things the enemy may possibly do(backup plans may be prepared for possible situations, of course). Similarly, someone going hiking in North America should prepare for bears, rather than komodo dragons or green unicorns.


Yes, that's the point of reasonable speculation.



With Stephen Hawking's speculation in particular, the danger is that we refrain from performing some sort of scientific investigation out of fear that it will reveal our existence. How much high-profile investigation we do should be based on how likely it is that there is alien life which will detect it, rather than on whether or not alien life might be able to detect it.

A weakness of Hawking's idea is that it fails to consider that an intelligence that has become capable of interstellar travel is probably also quite self sufficient. So what need would their be for a hostile takeover of earth?

ASTRO BOY
2012-Nov-30, 08:47 PM
A weakness of Hawking's idea is that it fails to consider that an intelligence that has become capable of interstellar travel is probably also quite self sufficient. So what need would their be for a hostile takeover of earth?

Yep, quite agree with that reasoning.

KABOOM
2012-Nov-30, 10:50 PM
You're coming up with science fictional scenarios - possibly even good ones, possibly even ones that will turn out to be true - but they are nevertheless nothing more than speculation.

Surely it's anthropomorphic thinking to suppose the aliens will follow the same path of us with electronics?

And what's so significant about faster synapses? Surely that just means the post-humans will see the world slow down. And given that electronics are more durable, is it even necessary for the synapses to be faster? A 10 millisecond delay might be handy when you're waiting for your favourite TV programme to come on.

Just read Ray Kurzweil's latest, "How to Create a Mind". Kurzweil is smarter and more accomplished than most otherwise very smart folks who post on these boards. The man is a true pioneer in AI and brain technology. He sees this transformation happening before mid-century and take you through the science behind it in his latest book. To me the only way that this doesn't happen is that society gets DERAILED via AGW consequences (which are very likely).

TooMany
2012-Nov-30, 11:36 PM
Just read Ray Kurzweil's latest, "How to Create a Mind". Kurzweil is smarter and more accomplished than most otherwise very smart folks who post on these boards. The man is a true pioneer in AI and brain technology. He sees this transformation happening before mid-century and take you through the science behind it in his latest book. To me the only way that this doesn't happen is that society gets DERAILED via AGW consequences (which are very likely).

We have to face up to this because it's going to happen. I haven't read his book but I just read the intro and I have seen articles about him. Mid-century seems way too soon to me for this to happen unless he has some inside information. He seems to exaggerate a lot. He talks about the IBM Watson playing Jeopardy! as if the computer understands the phrases that it guesses.

It's fair to say that we do not yet know how human brains function (or even fly brains) except at the level of small groups of nerves. But the way biological brains function is quite different from any software/hardware that I heard about. There is massive parallelism for one thing. It seems that the whole architecture is completely different from current computer architecture.

Nevertheless, the fact remains that electronics can mimic any computational process performed by neurons in the brain and do it about 1 million times faster. There are some folks (I'll have to look it up) who are conjecturing how the neo-cortex works (based on studies of the neural structure). They are trying to implement something similar in circuitry. I can see us making some progress by mid century, but human capacity seems doubtful. We are waiting for a breakthrough in machine organization, but we may be able to cheat and just copy nature.

There is good reason to believe that artificial intelligence will progress fast enough to outstrip any real value to sending men on space missions instead of robots. If we ever do meet the aliens, my bet is that they won't be biochemical life forms.

NoChoice
2012-Dec-01, 01:07 AM
Nevertheless, the fact remains that electronics can mimic any computational process performed by neurons in the brain and do it about 1 million times faster. There are some folks (I'll have to look it up) who are conjecturing how the neo-cortex works (based on studies of the neural structure). They are trying to implement something similar in circuitry. I can see us making some progress by mid century, but human capacity seems doubtful. We are waiting for a breakthrough in machine organization, but we may be able to cheat and just copy nature.
I am with you that electronics and software technologies will be able to emulate human intelligence to some degree, very likely even outperform us in certain aspects.

However, I don't think (and that is just my personal opinion) it will lever come close to the real deal, i.e. replacing a human. Consciousness is a unique quality. I am convinced it is an immaterial "entity" for lack of a better word. And no electronic and/or software emulation will be able to replace that. I am open, however, to the possibility and I would find that highly interesting.
Kurzweil's approach suffers from the same limitation as most scientist's approach does: it is a materialistic approach, and therefore inherently limited and unable to even ask the proper questions.

I freely admit that at this point I have little more than my gut feeling to "support" this hypothesis. And my reasoning that I don't see the qualities of consciousness anywhere else in the material world.


There is good reason to believe that artificial intelligence will progress fast enough to outstrip any real value to sending men on space missions instead of robots. If we ever do meet the aliens, my bet is that they won't be biochemical life forms.

I strongly disagree. There is something unique happening when you send a human consciousness to new frontiers. When those humans come back they share their experience on many levels. It is not just information gathering that electronic/software entities could perform. It is much more. It is again that immaterial quality unique to consciousness that enables the sharing on "higher" levels. Limiting ourselves to machines is just not the same and I doubt it will ever be.

TooMany
2012-Dec-01, 02:19 AM
However, I don't think (and that is just my personal opinion) it will lever come close to the real deal, i.e. replacing a human. Consciousness is a unique quality. I am convinced it is an immaterial "entity" for lack of a better word. And no electronic and/or software emulation will be able to replace that. I am open, however, to the possibility and I would find that highly interesting.


To be honest, I don't know what we really are, what existence is, what consciousness is or what the physical world is. However, taking the "objective" philosophical position of science, we are physical beings, not spirits. We are part of the physical world and arose from the physical world. If I accept that premise (this scientific view of reality) I cannot deny that artificial intelligence at a level that equals humans is possible.



Kurzweil's approach suffers from the same limitation as most scientist's approach does: it is a materialistic approach, and therefore inherently limited and unable to even ask the proper questions.

I freely admit that at this point I have little more than my gut feeling to "support" this hypothesis. And my reasoning that I don't see the qualities of consciousness anywhere else in the material world.


You can experience consciousness in yourself but only guess that others are also conscious.



I strongly disagree. There is something unique happening when you send a human consciousness to new frontiers. When those humans come back they share their experience on many levels. It is not just information gathering that electronic/software entities could perform. It is much more. It is again that immaterial quality unique to consciousness that enables the sharing on "higher" levels. Limiting ourselves to machines is just not the same and I doubt it will ever be.

Perhaps, but in hostile environments we will always be isolated from where we are, e.g. by a space suit. I cannot fly around the world at will, but I can get a primitive facsimile of that using Google Earth. The same sort of thing could be done (in the distant future) in a much more realistic way to allow all of us, not just a few astronauts, experience what it is like to be on Mars.

whimsyfree
2012-Dec-01, 04:10 AM
There is good reason to believe that artificial intelligence will progress fast enough to outstrip any real value to sending men on space missions instead of robots. If we ever do meet the aliens, my bet is that they won't be biochemical life forms.

I bet it wont be before we wont be biochemical life forms either.



A weakness of Hawking's idea is that it fails to consider that an intelligence that has become capable of interstellar travel is probably also quite self sufficient. So what need would their be for a hostile takeover of earth?

Nothing. I don't think that is the concern.


On the other hand, the statement "We don't know whether or not ghosts exist." is clear, unbiased and leaves little room for interpretation.

It's also uninformative because you would make the same statement about any subject. Science (at least your version of it) never knows anything with certainty. The reality of science is different. In areas of science where ghosts come up, such as in psychology, it is routinely assumed that they don't exist.

NoChoice
2012-Dec-01, 04:22 AM
It's also uninformative because you would make the same statement about any subject. Science (at least your version of it) never knows anything with certainty.

It is as informative as the current state of knowledge allows it to be. In case we have no evidence one way or the other (as in the case of whether aliens exist at all, or have been visiting earth), the answer must be: "We don't know." No other answer is scientifically honest.

How you arrive at the conclusion that I "would make that statement about any subject" is very puzzling. We know that electrons exist. We have many reproducible experiments that clearly show their existence. We don't know exactly what they are but we certainly know that they are.


In areas of science where ghosts come up, such as in psychology, it is routinely assumed that they don't exist.
I am aware of that. I would accept that assumption as a currently acceptable hypothesis. But I would reject it as a declaration of a scientific fact. It isn't a fact. The fact is we don't know whether or not they exist.

R.A.F.
2012-Dec-01, 06:35 PM
I was staying out of this thread, but since this does not involve Toomany, and since I just can't allow the following to pass without comment....



The fact is we don't know whether or not they exist.

I am reminded of the Asimov quote...

Where any answer is possible, all answers are meaningless.



edit to add...and I see you've tried arguing the same on the "spiderwebs" thread...

ASTRO BOY
2012-Dec-01, 08:09 PM
I am reminded of the Asimov quote...

Where any answer is possible, all answers are meaningless.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>





Nice quote amongst a range of interesting quotes I often use.

In a situation like this I like comparing it to any scientific theory......We can never be really sure any theory aligns with the true reality of any situation...We model according to observational and experimental evidence and possibly modify or scrap over time.

With the question of the existance of ET life, we have the presence of all the ingrediants of life everywhere we look, and a near infinite number of astronomical bodies to take a foothold on.

In my opinion like any scientific theory, we can be confident of the existance of ET life without 100% certainty......Intelligent ET life slightly less confident but with the odds still in favour of the affirmative.

Even if we fail to find convincing evidence of ET life in the next thousand years, we can never be sure that it does not exist due to the near infinite extent of the Universe.

Selfsim
2012-Dec-01, 08:34 PM
The fact is we don't know whether or not they exist.I am reminded of the Asimov quote...

Where any answer is possible, all answers are meaningless.… and that says it all as far as I'm concerned, too.

Selfsim
2012-Dec-01, 09:19 PM
… We can never be really sure any theory aligns with the true reality of any situation…The problem is that others here seem to think that they can infer a 'true reality', and then things which are consequentially implied to exist within it! This is done by word-play using terms like 'possible, 'plausible', 'likely' and 'unlikely'. None of these terms so used, constitute physical reality. Physical evidence does.
As you say ...

We model according to observational and experimental evidence and possibly modify or scrap over time.Models can also be hypothetical. So, if we scrap or modify purely hypothetical models, this would imply that things created by means of terms like 'plausible' and 'possible', which depend on those models, might also suddenly cease to exist … in a puff of the very 'logic' which gave rise to the 'existence' of those things in the first place!

Omnipotence of the imagination, I tell ya!
Amazing stuff!


With the question of the existance of ET life, we have the presence of all the ingrediants of life everywhere we look, and a near infinite number of astronomical bodies to take a foothold on.

In my opinion like any scientific theory, we can be confident of the existance of ET life without 100% certainty......Intelligent ET life slightly less confident but with the odds still in favour of the affirmative.If the theoretical things which give rise to the view that ET life might exist, cannot be demonstrated to have consequences in the physical universe, then ET's existence is without physical meaning.


Even if we fail to find convincing evidence of ET life in the next thousand years, we can never be sure that it does not exist due to the near infinite extent of the Universe.What about the finite observable universe?
We are even theoretically unable to search every location within a finite, observable universe, (other than by philosophical constructs to do with infinite tasking .. which have Laws of Thermodynamics implications).

But we can falsify your proposition, by finding an instance of ET-life .. which is made theoretically possible because tests for carbon-based life exist. It may not be practical to execute those tests across the observable universe, however, which would also make your proposition not practically possible.

TooMany
2012-Dec-01, 10:55 PM
Where any answer is possible, all answers are meaningless.


… and that says it all as far as I'm concerned, too.

But it really doesn't say much at all, does it? In almost any situation (if you want argue for very remote possibilities) you can indeed argue that almost anything is possible. Using that fact, together with Asimov's postulate, you can conclude that all answer are meaningless in all situations.

You don't seem to make any distinction between "probable" and "possible". You treat them as identical. They are not. In mathematics a theorem is either true or false. In the real world the situation is quite different. We are not omniscient and we never really know exactly what will happen. Nevertheless we use our logical minds to project what the probabilities of something are based on past experience. When a rock is headed toward you don't say "well I don't know if that rock will hit my head so I should take no action", you duck.

TooMany
2012-Dec-01, 11:23 PM
I said:


A weakness of Hawking's idea is that it fails to consider that an intelligence that has become capable of interstellar travel is probably also quite self sufficient. So what need would their be for a hostile takeover of earth?




Nothing. I don't think that is the concern.


Do you mean that Hawking has a different worry in mind?

R.A.F.
2012-Dec-02, 12:46 AM
… and that says it all as far as I'm concerned, too.

It's a shame that Asimov isn't alive to participate in internet discussions. I can just imagine him moping up the floor with "alternative" thinkers. :D

Selfsim
2012-Dec-02, 01:10 AM
It's a shame that Asimov isn't alive to participate in internet discussions. I can just imagine him moping up the floor with "alternative" thinkers. :DI think the denial of distinctions which would otherwise lead to a more balanced view of reality, (in this case, the distinction of the state of 'unknown' and its 'implications'), is the main issue here.

All I've seen is a comment on, is that 'unknown' isn't saying much, (as if that couldn't possibly be the case .. ie: we must know)! :)

Uncoralled speculation and logic alone, cannot provide rational explanations for a physical universe, when there is no evidence basis for those speculations in the first place (ie: Nessie). Some seem to be absolutely convinced that it can!)

Asimov must've trodden this pathway himself.

eburacum45
2012-Dec-02, 01:38 AM
Uncoralled speculation and logic alone, cannot provide rational explanations for a physical universe, when there is no evidence basis for those speculations in the first place (ie: Nessie). Some seem to be absolutely convinced that it can!)

Asimov must've trodden this pathway himself.

Oh, he did. Here is one of his speculative essays on alien life and alternate life chemistries;
http://www.360doc.com/content/11/1008/08/7864784_154216041.shtml
if anything, his speculations are unbridled compared to many that have followed (but he was both a chemist and a science fiction writer).

Paul Wally
2012-Dec-02, 12:57 PM
Where any answer is possible, all answers are meaningless.

But it really doesn't say much at all, does it? In almost any situation (if you want argue for very remote possibilities) you can indeed argue that almost anything is possible. Using that fact, together with Asimov's postulate, you can conclude that all answer are meaningless in all situations.



I agree. A quote devoid of all context, will say what people want it to say. I'd just like to point out that an hypothesis is not an answer, it's merely a possible answer. So I would say, if there are many possible answers (hypotheses) then to simply choose one as the correct answer would be not to understand the meaning of "hypothesis".

R.A.F.
2012-Dec-02, 01:40 PM
I agree. A quote devoid of all context, will say what people want it to say.

Oh, you mean like absence of evidence is not evidence of absence?....which is most certainly devoid of all context and (as has been demonstrated on this thread) "fits" the category of "will say what people WANT it to say." :D

Sardonicone
2012-Dec-02, 02:42 PM
Seems like a moot point to me. We simply don't know. As of now our sample size is 1, which means life can exist in this universe.
Is there other life? I'd like to think so, but I have no evidence what so ever to back it up.

Selfsim
2012-Dec-02, 08:06 PM
I'd just like to point out that an hypothesis is not an answer, it's merely a possible answer. So I would say, if there are many possible answers (hypotheses) then to simply choose one as the correct answer would be not to understand the meaning of "hypothesis".Hypotheses aren't answers anyway .. unless one makes them so. (Frequently done around these parts too, I might add).

Anyone making use of an hypotheses as an answer, is on a philosophical quest, (typically masquerading as science).

Choosing one as a correct answer, demonstrates that the quest is to find the truth, and serves as an exclamation point signalling that science is being used as a substitute for some other condition, (eg: 'that exo-life exists' … which is empirically unsupportable in science).

I, (personally), suspect this particular characteristic of question/answer might be a hangover from science's academic (and counter-religious) origins, and anthropomorphically, anything stated, is deemed to be some kind response, to some kind of test the Universe is conducting upon humans.

The Asimov quote transcends this point however, as it could also be re-written (as far as intent is concerned) as:

"Where any hypothesis is possible, all hypotheses are meaningless.

Which more closely approximates the conclusions emerging from numerous discussions on matters of exo-life.

ASTRO BOY
2012-Dec-02, 08:10 PM
Seems like a moot point to me. We simply don't know. As of now our sample size is 1, which means life can exist in this universe.
Is there other life? I'd like to think so, but I have no evidence what so ever to back it up.


It maybe factual that we can not be 100% certain of the existence of ET life but the sheer size of the Universe and numbers involved certainly support the hypothesis of life elsewhere rather then the negative hypothetical view.

TooMany
2012-Dec-02, 08:45 PM
It maybe factual that we can not be 100% certain of the existence of ET life but the sheer size of the Universe and numbers involved certainly support the hypothesis of life elsewhere rather then the negative hypothetical view.

Nicely stated. Now let's hear how that is unscientific.

The Asimov article (http://www.360doc.com/content/11/1008/08/7864784_154216041.shtml) provided by eburacum45 should dispel the notion that he denid any value in scientific speculation.

Paul Wally
2012-Dec-02, 09:04 PM
"Where any hypothesis is possible, all hypotheses are meaningless."



You just equated 'hypothesis' with 'answer', which is what we both said it isn't. It doesn't even seem to make much sense to say an hypothesis is possible/impossible. Perhaps you mean that which the hypothesis is referring to is possible or impossible. In the case of exo-life speculation, any hypothesis is not 'possible' because the range of possibilities are constrained by the laws of physics.

Selfsim
2012-Dec-02, 09:36 PM
It maybe factual that we can not be 100% certain of the existence of ET life but the sheer size of the Universe and numbers involved certainly support the hypothesis of life elsewhere rather then the negative hypothetical view.Nicely stated. Now let's hear how that is unscientific.(Its nice to be so predictable … does that mean I might be ET-life, as well? .. I mean its possible, isn't it?)

Anyway seeing as a statistical argument has been raised (yet again) ... a challenge … I'd like to see someone show us, using classical mathematical axioms, and statistical methods/modelling (ie: 'show us the mathematics'), that: 'the sheer size of the Universe, and numbers involved 'support 'with certainty' the 'hypothesis of life elsewhere rather then the negative hypothetical view'.

(Of course, any assumed or estimated quantities, biasing the results, would negate any certainties so claimed).

Go ahead .. make my day!

Whaddya say TooMany (or ASTRO BOY): you both seem to have the skills??

PS: Perhaps a thread in the ATM forum might be appropriate for this claim, given that this is pretty much off-topic?

Selfsim
2012-Dec-02, 11:02 PM
You just equated 'hypothesis' with 'answer', which is what we both said it isn't.Nah .. I substituted …
It doesn't even seem to make much sense to say an hypothesis is possible/impossible. Perhaps you mean that which the hypothesis is referring to is possible or impossible. In the case of exo-life speculation, any hypothesis is not 'possible' because the range of possibilities are constrained by the laws of physics.If they're not constrained by the laws of Physics, then they're not hypotheses! (That eliminates them … )

Perhaps somewhat hidden in my questioning, is whether (or not), any 'hypothesis', (in the scientific meaning of the term), has to have any particular physical meaning, until test results are produced, which exclude any of the others, (or which results in it standing blatantly, 'head and shoulders' above the rest, from the very outset) ... hmm …{thinking ...} … If the basis of exclusion can be shown to be directly reasoned from the laws of Physics (excluding any woolly assumptions), then this brings us back to the same principle used in my first paragraph … That's consistent, isn't it? Hypotheses are by definition, not complete, so why should they be given specific physical meaning? Any physical meaning given them, would also be 'not complete', by the same definition .. thereby admitting possibilities in other aspects of the same, or other, hypotheses(?)

It seems that 'physical meaning' eliminates 'physical uncertainty' in the universe, for moi .. interesting … is there a problem with that approach?

(Admittedly, this is more a peripheral-to-science philosophical question, but hey … "When in Rome .. do as the Romans do", eh?)

Paul Wally
2012-Dec-03, 12:05 AM
Nah .. I substituted

By saying you've 're-written' Asimov's quote, I take that as equivalence. Because if they're not equivalent then you haven't re-written Asimov's , you've only written your own stuff.


…If they're not constrained by the laws of Physics, then they're not hypotheses! (That eliminates them … )

I disagree.


Perhaps somewhat hidden in my questioning, is whether (or not), any 'hypothesis', (in the scientific meaning of the term), has to have any particular physical meaning, until test results are produced, which exclude any of the others, (or which results in it standing blatantly, 'head and shoulders' above the rest, from the very outset) ... hmm …{thinking ...} … If the basis of exclusion can be shown to be directly reasoned from the laws of Physics (excluding any woolly assumptions), then this brings us back to the same principle used in my first paragraph … That's consistent, isn't it? Hypotheses are by definition, not complete, so why should they be given specific physical meaning? Any physical meaning given them, would also be 'not complete', by the same definition .. thereby admitting possibilities in other aspects of the same, or other, hypotheses(?)

It seems that 'physical meaning' eliminates 'physical uncertainty' in the universe, for moi .. interesting … is there a problem with that approach?

(Admittedly, this is more a peripheral-to-science philosophical question, but hey … "When in Rome .. do as the Romans do", eh?)

The basis of exclusion is contradictory evidence, as simple as that. That doesn't mean that when a scientist is devoting his research time on investigating one hypothesis, he is therefore excluding other hypotheses as invalid. Other scientists are free to investigate the alternative hypotheses. It's called division of labour!

What is your understanding of "physical meaning". I think that's where you get it wrong. You're equating physical meaning and existence.

Jens
2012-Dec-03, 12:13 AM
but I think a better answer is, "We have no reason to believe they exist."
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

We have plenty of reasons to believe they could exist.......The ingrediants of life being everywhere and the sheer weight of numbers multiplying the chances of the ingrediants assembling into life forms.

Sorry, I was talking about green unicorns, not aliens.

Jens
2012-Dec-03, 12:16 AM
It's a shame that Asimov isn't alive to participate in internet discussions. I can just imagine him moping up the floor with "alternative" thinkers. :D

I have a feeling that if Asimov were alive, he would probably do other things with his time than participate in Internet discussions. . .

whimsyfree
2012-Dec-03, 12:58 AM
Do you mean that Hawking has a different worry in mind?

You may be right about Hawking (http://www.msnbc.msn.com/id/36769422/ns/technology_and_science-space/t/hawking-aliens-may-pose-risks-earth/#.ULv1z4ZrL3A). According to that report he worries about aliens coming to conquer and colonize us for our resources. I don't worry about that. What would they want from us that they couldn't obtain more easily elsewhere? Minerals? rocky planets are made out of minerals and they are common. Energy? stars provide much more energy than we can. There might be aliens that want all the minerals and energy in the universe who will eventually come to consume Earth. We should have no trouble seeing such aliens coming.

The concern I had in mind was the less specific one that they might want to kill us.

Selfsim
2012-Dec-03, 03:04 AM
Because if they're not equivalent then you haven't re-written Asimov's , you've only written your own stuff.So?
I see no particular need for appeals to authority figures …
Do you?


…If they're not constrained by the laws of Physics, then they're not hypotheses! (That eliminates them … )I disagree.On what grounds? (Just curious … no accusations intended).

The basis of exclusion is contradictory evidence, as simple as that. That doesn't mean that when a scientist is devoting his research time on investigating one hypothesis, he is therefore excluding other hypotheses as invalid. Other scientists are free to investigate the alternative hypotheses. It's called division of labour!I'm not sure how that came into this(??)
Resource allocation would surely be external to the study of say, Physics, wouldn't you say?


What is your understanding of "physical meaning".Answering in the negative, actually better illustrates the term. There are many things which exist, which don't have physical meaning. Many mathematical constructs exist, for example, which don't have physical meaning, nor physical implications. Emotions exist, but don't necessarily have to have physical meaning, (even though they sometimes result in physical consequences).

There's nothing untoward about your question .. and I'm not trying to avoid it, but if one considers things which we don't necessarily associate with any particular physical meaning, then right there, you'll get what I mean by 'physical meaning' .. and that's where untested hypotheses exist.

'Physical meaning' is something we choose to assign to something else, which has been sourced by a process which enables that 'something else' to be: (i) objectifiable, (ie for eg: able to stated, documented, published, etc); (ii) independently verifiable and quantifiable, in ('physical') terms such as: distance, time and form, and (iii) which also presents as being internally consistent. The examples I cited above, don't necessarily match that criteria.

What's your understanding of it?

I think that's where you get it wrong. You're equating physical meaning and existence.Wrong, eh? Well, thank you for that determination.
Where exactly in the answer section of a science or math textbook, would I find that particular 'fact'?
(I'm a hopeless cheat when it comes to checking the answers first, y'know … :) )

Hornblower
2012-Dec-03, 04:10 AM
Let's get back to the issue raised in the OP. Too many times in the linked article we see the phrase "aliens don't exist" when all that can be inferred from a lack of verifiable observations thereof is "alien incursions on or near Planet Earth probably do not occur."

Unlike some of us, I am skeptical about the idea that advanced intelligent beings inevitably would be able to conquer the natural barriers to interstellar missions. I would want to see some real engineering progress beyond the launching of a few small, slow robot vehicles before I would change my mind.

Selfsim
2012-Dec-03, 04:48 AM
… Unlike some of us, I am skeptical about the idea that advanced intelligent beings inevitably would be able to conquer the natural barriers to interstellar missions. I would want to see some real engineering progress beyond the launching of a few small, slow robot vehicles before I would change my mind.Why limit your skepticism to that, when there's a myriad of other reasons to be skeptical … like being skeptical about the existence of 'advanced intelligent beings' in the physical universe in the first place?

Why limit your concerns to what they may, or may not be able to do in the physical universe, (like 'conquer'), if they might not exist in it, in the first place?

...before I would change my mind.
.. It seems the 'mind' might be the primary source of these concerns.
… Hmm … I know!! … Just change it right now, and your concerns might disappear in an instant!

Go ahead .. give it a try! After all, there are no {real} reasons not to!

vanluongpro
2012-Dec-03, 06:34 AM
yes I also think that there are no aliens.

Paul Wally
2012-Dec-03, 10:57 AM
So?
I see no particular need for appeals to authority figures …
Do you?


This is what you wrote:

The Asimov quote transcends this point however, as it could also be re-written (as far as intent is concerned) as:

"Where any hypothesis is possible, all hypotheses are meaningless.

So I take it that the underlined is in fact false, based on your reply above. What you wrote doesn't follow from Asimov's quote nor does it have the same intent.




…If they're not constrained by the laws of Physics, then they're not hypotheses! (That eliminates them … )


I disagree, because an hypothesis gets eliminated by contrary evidence not a priori convictions. Scientists are free to hypothesise whatever they want, as long as they call it what it is. What if a physicist wants to hypothesize that the known laws of physics break down under certain conditions or that there are many universes with different laws of physics than ours?




Originally Posted by [B]Paul Wally
The basis of exclusion is contradictory evidence, as simple as that. That doesn't mean that when a scientist is devoting his research time on investigating one hypothesis, he is therefore excluding other hypotheses as invalid. Other scientists are free to investigate the alternative hypotheses. It's called division of labour!
I'm not sure how that came into this(??)
Resource allocation would surely be external to the study of say, Physics, wouldn't you say?

Are you sure that you're not sure, because you're missing the point completely. Just because an astrobiologist is not interested in investigating the hypothesis: "non-existence of life beyond planet Earth and the international space station", that doesn't mean that he/she eliminated the hypothesis as false. Other scientists are free to choose that as their research topic.



Answering in the negative, actually better illustrates the term. There are many things which exist, which don't have physical meaning. Many mathematical constructs exist, for example, which don't have physical meaning, nor physical implications. Emotions exist, but don't necessarily have to have physical meaning, (even though they sometimes result in physical consequences).

So then you are trying to avoid answering the question. It is clear that when we speak of the existence of extraterrestrial life, that we are speaking of physical existence, not mathematical existence. The term life already has physical meaning and other planets have physical meaning too, therefore the idea that there's life on other planets has physical meaning too. That doesn't necessarily mean that life on other planets exists. For some reason it might not exist, but that doesn't make the idea of their existence physically meaningless.



Wrong, eh? Well, thank you for that determination.
Where exactly in the answer section of a science or math textbook, would I find that particular 'fact'?
(I'm a hopeless cheat when it comes to checking the answers first, y'know … :) )

Yes wrong, as in fallacious. Don't cheat, just try answering the question: Do you equate physical meaning with physical existence? If yes, the absurdities should start popping out.

NoChoice
2012-Dec-03, 11:34 AM
I disagree, because an hypothesis gets eliminated by contrary evidence not a priori convictions. Scientists are free to hypothesise whatever they want, as long as they call it what it is. What if a physicist wants to hypothesize that the known laws of physics break down under certain conditions or that there are many universes with different laws of physics than ours?

That is exactly right. I would only add that in practice the choice of a hypothesis can be a complex process, which not only involves purely scientific considerations but is also influenced by peer feedback and funding requirements.
But theoretically and principally a scientist can choose a hypothesis freely. Of course, in order to elevate a hypothesis to a theory supporting evidence and reproducible procedures are essential and many hypotheses do not pass those requirements.

As far as the question of extraterrestrial visitations is concerned and to the best of my knowledge none of the major hypotheses meets any of the requirements to elevate it to a theory. The question is therefor unanswerable (at least at this point in time) and the only proper scientific stance is - you guessed it - "We don't know".

R.A.F.
2012-Dec-03, 02:14 PM
Perhaps a thread in the ATM forum might be appropriate for this claim, given that this is pretty much off-topic?

Naw....posters on this thread know that they can make any claim they like as long as it is "speculative". You won't catch them on the ATM section of the board, because they would then be compelled to "back up" their claims with evidence.

Aside...this thread has gone so far off topic, that I don't know why it hasn't been split...

R.A.F.
2012-Dec-03, 02:21 PM
But it really doesn't say much at all, does it?

Oh, you mean just like absence of evidence is not evidence of absence doesn't say much, yet it is being used by those who don't want to be criticised for their speculation. :D

R.A.F.
2012-Dec-03, 02:27 PM
What you wrote doesn't follow from Asimov's quote nor does it have the same intent.

Will you be addressing my post with the original Asimov quote?....you seem to have overlooked it.

Swift
2012-Dec-03, 02:38 PM
Let's get back to the issue raised in the OP.
I'm not going to review 150+ posts to find out when you folks started wandering so far off topic, but I'm not seeing how much of this current discussion has anything to do with the OP. If people want to have a discussion about "physical meaning and existence", start a new thread. I'd suggest following Hornblower's good advice and get back on topic, or we will just close this thread.

R.A.F.
2012-Dec-03, 03:31 PM
As per Swift's instruction, please disregard post #162 through post #164 as they are not relevant to the OP.


On topic...If aliens are interested enough to visit us, then why would they "hide" from us?

....and if they intend to hide from us, they why are they seen at all?

Given the technology to travel multi-lightyear distances, they should possess the technology to remain completely unobserved...yet "they" fly around with bright lights ablazing.

...makes no sense at all...

TooMany
2012-Dec-03, 05:42 PM
The concern I had in mind was the less specific one that they might want to kill us.

Seems to be one of our favorite pass times (domination of others and their property), but it's hard to imagine that would be a goal of a fully self-sufficient intelligence. Let's suppose that even a single space-faring civilization evolved in the galaxy one billion years ago. Suppose these aliens are hostile or greedy and want to conquer everything in sight. It's quite conceivable that this could be accomplished through self-replicating machines that spread in all directions. At 1/10 light-speed travel, a complete domination of the galaxy could happen within a mere million years. Thus we already have evidence that so-motivated aliens do not exist. In my mind that is not evidence that aliens and interstellar travel do not exist. Maybe this is just my fantasy, but I would bet on such advanced intelligence having different, less-intrusive goals similar to the "prime directive".

TooMany
2012-Dec-03, 05:52 PM
As per Swift's instruction, please disregard post #162 through post #164 as they are not relevant to the OP.


On topic...If aliens are interested enough to visit us, then why would they "hide" from us?

....and if they intend to hide from us, they why are they seen at all?

Given the technology to travel multi-lightyear distances, they should possess the technology to remain completely unobserved...yet "they" fly around with bright lights ablazing.

...makes no sense at all...

I very much doubt (just my opinion) that these sightings have anything to do with aliens except in people's imagination. Are you making the assumption that these reports of alien encounters must be true if aliens actually exist? Or perhaps that if aliens did exist and visited earth they would want to meet us or interfere for some reason?

R.A.F.
2012-Dec-03, 06:38 PM
I very much doubt (just my opinion) that these sightings have anything to do with aliens except in people's imagination.

People believing that aliens are visiting us right now is the topic of this thread. edit to be precise... the lack of evidence that aliens are visiting us right now, is the topic of this thread.



Are you making the assumption that these reports of alien encounters must be true if aliens actually exist? Or perhaps that if aliens did exist and visited earth they would want to meet us or interfere for some reason?

No.

TooMany
2012-Dec-03, 07:28 PM
People believing that aliens are visiting us right now is the topic of this thread. edit to be precise... the lack of evidence that aliens are visiting us right now, is the topic of this thread.


OK if that topic is that limited then, yes I agree there is no good evidence that aliens are visiting us right now. However, that does not exclude the possibility that we are observed. It could even be that the aliens have seen so many civilizations, they have hardly any particular interest in ours and don't visit. What I strongly disagree with is that the absence of real "alien sightings" is good evidence that they don't exist at all. It can only be such good evidence under the assumptions that they are actually interested in visiting us and that they want to be noticed or that they cannot avoid observation, all of which are open to serious doubt.

The headline says "expert says aliens dont exist". Perhaps what the headline really means is that "these sightings are not evidence of alien visitation". If that's what it means, it's a rather poor way of stating it since it seems to imply much more.

R.A.F.
2012-Dec-03, 07:39 PM
OK if that topic is that limited then, yes I agree there is no good evidence that aliens are visiting us right now.

Then it seems we're done, here...


However, that does not exclude the possibility that we are observed. It could even be that the aliens have seen so many civilizations, they have hardly any particular interest in ours and don't visit. What I strongly disagree with is that the absence of real "alien sightings" is good evidence that they don't exist at all. It can only be such good evidence under the assumptions that they are actually interested in visiting us and that they want to be noticed or that they cannot avoid observation, all of which are open to serious doubt.

The headline says "expert says aliens dont exist". Perhaps what the headline really means is that "these sightings are not evidence of alien visitation". If that's what it means, it's a rather poor way of stating it since it seems to imply much more.

No.

Selfsim
2012-Dec-03, 07:49 PM
I think I'm finished here, too.

ASTRO BOY
2012-Dec-04, 08:17 PM
(Its nice to be so predictable … does that mean I might be ET-life, as well? .. I mean its possible, isn't it?)

Anyway seeing as a statistical argument has been raised (yet again) ... a challenge … I'd like to see someone show us, using classical mathematical axioms, and statistical methods/modelling (ie: 'show us the mathematics'), that: 'the sheer size of the Universe, and numbers involved 'support 'with certainty' the 'hypothesis of life elsewhere rather then the negative hypothetical view'.

(Of course, any assumed or estimated quantities, biasing the results, would negate any certainties so claimed).

Go ahead .. make my day!

Whaddya say TooMany (or ASTRO BOY): you both seem to have the skills??

PS: Perhaps a thread in the ATM forum might be appropriate for this claim, given that this is pretty much off-topic?



I find nothing wrong in reasonable speculation.
The sheer statistical numbers and extent of the Universe make the speculation that ET life exists quiet reasonable I would think. That and of course the basic ingrediants of life being everywhere we look, reinforces that speculation.

Most cosmologists while adhering to the very scientifically correct assumption that "we don't really know" will still express their thoughts to the affirmative position to the question if they are asked for an opinion.

In a similar way we make valid assumptions that the Universe is homogenious and isotropic based on a small example we call our "Observable Universe"

Selfsim
2012-Dec-04, 08:58 PM
It maybe factual that we can not be 100% certain of the existence of ET life but the sheer size of the Universe and numbers involved certainly support the hypothesis of life elsewhere rather then the negative hypothetical view.Nicely stated. Now let's hear how that is unscientific.


I find nothing wrong in reasonable speculation ...Hi Astro Boy;

… Except you did not state the above as being speculative.
You stated the support as being 'certain' (see my underline). It is not. .. either in a mathematical paradigm, or in mainstream science terms. I'd even disagree with its certainty in common language terms. The 'numbers' are just numbers. People are what create inferences drawn from them, and there is insufficient evidence to establish inference for a conclusion of any certainty. The honest conclusion is 'unknown'.

Exercising some caution in language usage 'round these parts, is always a wise tactic … (especially when rigor is being brought to bear in a conversation). I apologise if I appeared as being somewhat brutal … you are only new here. Good to have ya around, and I look forward to your future contributions :)


In a similar way we make valid assumptions that the Universe is homogenious and isotropic based on a small example we call our "Observable Universe"Homogeneity and isotropy apply to the physics of the large scale universe (and Cosmology), and have an empirical basis. No-one has ever established a causal relationship (in theoretical terms), between these working principles, and the emergence of life amongst isolated 'worlds'. Until there is one, such an 'assumption' is not theoretically validated.

Cheers

R.A.F.
2012-Dec-04, 09:05 PM
I find nothing wrong in reasonable speculation.

The sheer statistical numbers and extent of the Universe make the speculation that ET life exists quiet reasonable I would think. That and of course the basic ingrediants of life being everywhere we look, reinforces that speculation.

Most cosmologists while adhering to the very scientifically correct assumption that "we don't really know" will still express their thoughts to the affirmative position to the question if they are asked for an opinion.

In a similar way we make valid assumptions that the Universe is homogenious and isotropic based on a small example we call our "Observable Universe"

What does any of this have to do with the topic of this thread????

TooMany
2012-Dec-04, 10:06 PM
… Except you did not state the above as being speculative.
You stated the support as being 'certain' (see my underline).

It seems that you have seriously misunderstood Astro Boy's intent. He said "numbers involved certainly support the hypothesis of life elsewhere".

Selfsim
2012-Dec-04, 10:35 PM
It seems that you have seriously misunderstood Astro Boy's intent. He said "numbers involved certainly support the hypothesis of life elsewhere".No .. the 'numbers involved', exhibit no 'certain' support of this, at all.
If they do, please demonstrate this certainty, in the conventional paradigm for doing so, when dealing with matters related with numeracy.

TooMany
2012-Dec-04, 11:13 PM
No .. the 'numbers involved', exhibit no 'certain' support of this, at all.
If they do, please demonstrate this certainty, in the conventional paradigm for doing so, when dealing with matters related with numeracy.

You still fail to understand the remark. An "hypothesis" is not a certainty. Here's a definition of the word that applies:

hypothesis: a tentative assumption made in order to draw out and test its logical or empirical consequences

ASTRO BOY
2012-Dec-05, 12:39 AM
Hi Astro Boy;

… Except you did not state the above as being speculative.
You stated the support as being 'certain' (see my underline). It is not. .. either in a mathematical paradigm, or in mainstream science terms. I'd even disagree with its certainty in common language terms. The 'numbers' are just numbers. People are what create inferences drawn from them, and there is insufficient evidence to establish inference for a conclusion of any certainty. The honest conclusion is 'unknown'.

Exercising some caution in language usage 'round these parts, is always a wise tactic … (especially when rigor is being brought to bear in a conversation). I apologise if I appeared as being somewhat brutal … you are only new here. Good to have ya around, and I look forward to your future contributions :)

Homogeneity and isotropy apply to the physics of the large scale universe (and Cosmology), and have an empirical basis. No-one has ever established a causal relationship (in theoretical terms), between these working principles, and the emergence of life amongst isolated 'worlds'. Until there is one, such an 'assumption' is not theoretically validated.

Cheers

Hi Selfism....First let me say I didn't notice any brutality in your style at all....pedantic maybe but not brutal. :-)
Plus I'm no shrinking Violet and am also not a professional in these areas of expertise....I am a retired maintainance Fitter from Sydney who has a fanatical interest in all things astronomical and cosmological and what little knowledge I do have has been gained by much reading of books by Michio Kaku, Paul Davis, Mitch Begalman, Sir Martin Rees and Kip Thorne amongst others.
And in all respects I'm still learning.

I also try to look at things as simply as possible like Occam and his razor.
In that respect I disagree with your "numbers are just numbers" bit.
If for instance we knew the Universe was Infinite, we could then be certain that life similar or the same as us did exist.
If you knew there was to be a lottery next week for a million dolllars and only 10 tickets to be sold, your chances of winning are far greater then the more conventional lottery where they sell a million tickets.
The inferences as you put itare logical deductions as I see it.
In my own speculative Imaginative mind though, I see the existance of ET as near certain despite that being in "conflict" with the more proper scientific answer of "We don't know".


OK, I've stuck my neck out so don't be backward in chopping it off if that is how you see it.

Thanks for the welcome also, much appreciated.

ASTRO BOY
2012-Dec-05, 12:47 AM
No .. the 'numbers involved', exhibit no 'certain' support of this, at all.
If they do, please demonstrate this certainty, in the conventional paradigm for doing so, when dealing with matters related with numeracy.



The numbers support the "hypothesis" of life elsewhere....certainly not the "certainty" of life elsewhere.
For example if there were only 10 other stellar systems in the Universe as opposed to a near infinite number, the hypothesis of life elsewhere would be much less......If the ingrediants for life were only found in our solar system, the existance for life elsewhere would be non existent.

neilzero
2012-Dec-05, 01:24 AM
"If they intend not to be seen, why do they hide from us at all?" To be seen in improbable situations is taken as tall tales by most of the important people = the aliens show them selves selectively to people who are thought to be fools by most of us. If the aliens living on Earth can trick most of the important people, the opinions of the rest of us hardly matters. While this is likely a rasonable hypothesis, it neither establishes, nor debunks ET liveing among us. Neil

neilzero
2012-Dec-05, 01:51 AM
Since we don't know, and the probability of ET visiting Earth with horrible results for humans is not zero, perhaps we should minimise extreme effective radiated levels of radio energy escaping Earth, where this can be done at moderate cost = unthered high altitude balloon transponders instead of launching more GEO communications satellites for communication up to about two hundred kilometers. Uplinks to balloons can be less powerful and the changing direction of the narrow uplink beam less predictable for ET observers, if any. Neil

Selfsim
2012-Dec-05, 09:42 AM
An "hypothesis" is not a certainty.

Here's a definition of the word that applies:

hypothesis: a tentative assumption made in order to draw out and test its logical or empirical consequences
Irrelevant.

Please answer the question from post #150 (http://cosmoquest.org/forum/showthread.php/139400-expert-says-aliens-dont-exist?p=2085041#post2085041) (in a new thread ..).

mkline55
2012-Dec-05, 08:54 PM
I've just read many of the posts here, skipping only to avoid topic drift. Interesting points from several people. I only saw brief mentions of "life as we know it." Would we even recognize life as we do not know it? If we did not recognize other forms of life, how could we say they did or did not exist? And, if that life did not evolve into a technological civilization, it would never visit earth intentionally. A few posts put out some numbers of say a maximum of 1 life-supporting planet per 1000 stars. Then, looking at stars within a 150 lightyear radius... What about timing? Earth supported life for what - a billion years or two - maybe three? We've only been sending radio signals for a tiny portion of that time. Statistically, there are too few stars within a 150 lightyear radius for a technologically equivalent species to receive our signals. Even with the hopeful estimates, the few thousand nearest stars each have lass than 150/1000/1,000,000,000 chance of hearing. That's highly unlikely.

On the other hand, if a civilization achieved interstellar travel by any means we currently understand, it would be at great expense of energy and time. Something like 10,000 to 100,000 years to get from one star to another. Could the travelers survive? The originating civilization could be long gone in that time. In the interest of survival of life, a more plausible approach seems to be to send probes containing the simplest life forms, such as bacteria and viruses. Those forms could potentially survive for many generations of travel between stars. If they arrived someplace that supported their simple needs, they could then eventually evolve to fit the environment better, and life could go on. Who's to say life could not have travelled among the stars in just that way? Wouldn't those life forms be aliens to wherever they came? Would we still say aliens never come to visit?

TooMany
2012-Dec-05, 09:21 PM
I've just read many of the posts here, skipping only to avoid topic drift. Interesting points from several people. I only saw brief mentions of "life as we know it." Would we even recognize life as we do not know it? If we did not recognize other forms of life, how could we say they did or did not exist? And, if that life did not evolve into a technological civilization, it would never visit earth intentionally. A few posts put out some numbers of say a maximum of 1 life-supporting planet per 1000 stars. Then, looking at stars within a 150 lightyear radius... What about timing? Earth supported life for what - a billion years or two - maybe three? We've only been sending radio signals for a tiny portion of that time. Statistically, there are too few stars within a 150 lightyear radius for a technologically equivalent species to receive our signals. Even with the hopeful estimates, the few thousand nearest stars each have lass than 150/1000/1,000,000,000 chance of hearing. That's highly unlikely.

On the other hand, if a civilization achieved interstellar travel by any means we currently understand, it would be at great expense of energy and time. Something like 10,000 to 100,000 years to get from one star to another. Could the travelers survive? The originating civilization could be long gone in that time. In the interest of survival of life, a more plausible approach seems to be to send probes containing the simplest life forms, such as bacteria and viruses. Those forms could potentially survive for many generations of travel between stars. If they arrived someplace that supported their simple needs, they could then eventually evolve to fit the environment better, and life could go on. Who's to say life could not have travelled among the stars in just that way? Wouldn't those life forms be aliens to wherever they came? Would we still say aliens never come to visit?

The hypothesis that they are stuck with our space technology or that the "costs" would be too high isn't worth considering if we simply assume the continued (and foreseeable) development of technology far beyond what we currently possess. Maybe I'm crazy, but isn't the obvious solution to long trips to send autonomous machines rather the biological specimens whether intelligent or not? It would be rather short-sighted of us to think that we would certainly detect alien visits unless they were microscopic.

Life could have been deliberately seeded by aliens with probes like you mention. But on that subject, I just don't think it would be necessary (or even particularly interesting for the aliens). Imagine if we found life on Mars only to discover that we seeded it by accident. Kind of disappointment rather than a goal.

mkline55
2012-Dec-06, 02:07 PM
The hypothesis that they are stuck with our space technology or that the "costs" would be too high isn't worth considering if we simply assume the continued (and foreseeable) development of technology far beyond what we currently possess. Maybe I'm crazy, but isn't the obvious solution to long trips to send autonomous machines rather the biological specimens whether intelligent or not? It would be rather short-sighted of us to think that we would certainly detect alien visits unless they were microscopic.

Life could have been deliberately seeded by aliens with probes like you mention. But on that subject, I just don't think it would be necessary (or even particularly interesting for the aliens).

The idea of sending machines only works if they could be sent in a reasonable time frame. Even with some imaginary transportation method, it could take generations to get a machine to another star's planets. Who would be around to watch for the results?

TooMany
2012-Dec-06, 10:01 PM
The idea of sending machines only works if they could be sent in a reasonable time frame. Even with some imaginary transportation method, it could take generations to get a machine to another star's planets. Who would be around to watch for the results?

For the machine that goes there, that may be the end in itself. Just to go and see and never go back. Also perhaps the other machines will patiently wait for the results.

The idea that aliens must be biological beings (because they originated that way) places limitations on the aliens that are not realistic.

whimsyfree
2012-Dec-07, 01:12 AM
The idea of sending machines only works if they could be sent in a reasonable time frame. Even with some imaginary transportation method, it could take generations to get a machine to another star's planets. Who would be around to watch for the results?

That's a good point and a reason why humans wont be sending any interstellar probes for the foreseeable future. Aliens could have a combination of longer time horizons and better technolgies that make it worthwhile. They could also have motivations other than scientific payoff to the sender.

Justsomeinput
2012-Dec-13, 05:10 AM
Everyone seems to assume that "aliens" are technologically superior to us. Maybe we're one of the most advanced, superior beings...

R.A.F.
2012-Dec-13, 06:24 PM
[B]Everyone seems to assume that "aliens" are technologically superior to us.[\B]

Not everyone.



Oh.....and welcome to board!

Luckmeister
2012-Dec-13, 06:29 PM
Everyone seems to assume that "aliens" are technologically superior to us. Maybe we're one of the most advanced, superior beings...

No one I'm aware of here assumes that. The discussion in this thread has mainly focused on aliens advanced enough to be detected or to visit Earth.

R.A.F.
2012-Dec-13, 06:33 PM
No one I'm aware of here assumes that.

That's "debatable" IMHO.

Selfsim
2012-Dec-13, 07:23 PM
The idea that aliens must be biological beings (because they originated that way) places limitations on the aliens that are not realistic.You're making a call based on realism, when speaking of 'aliens'??

TooMany
2012-Dec-13, 10:05 PM
You're making a call based on realism, when speaking of 'aliens'??

Yes, I am. Is the word "alien" equivalent to "leprechaun" in your mind? You need only use your mind, examine your surroundings, learn a little bit about life and evolution, learn about our solar system and it's planets and then absorb the little that we already know about other systems and then factor in the number of suitable stars in the galaxy to quite scientifically propose a hypothesis that alien life exists.

Why bother? If your not interested in examining possibilities, why do you hang around? You just repeatedly make the point that "we do not know" and therefore.... what?

TooMany
2012-Dec-13, 10:19 PM
Everyone seems to assume that "aliens" are technologically superior to us. Maybe we're one of the most advanced, superior beings...

That's possible, but it requires the coincidence that we are the first technological beings. Intelligent life could have evolved (as it has on Earth) a billion years ago in some system or a billion years from now in another. The assumption that we are the first is just that, and not at all likely if technological civilizations are a common occurrence (say 1 out of 1,000,000,000 systems).

People are not implying that there is no life less developed than Earth life. But those life forms won't be traveling among the stars so they are not so much the subject of this discussion.

Swift
2012-Dec-13, 10:24 PM
Yes, I am. Is the word "alien" equivalent to "leprechaun" in your mind? You need only use your mind, examine your surroundings, learn a little bit about life and evolution, learn about our solar system and it's planets and then absorb the little that we already know about other systems and then factor in the number of suitable stars in the galaxy to quite scientifically propose a hypothesis that alien life exists.

Why bother? If your not interested in examining possibilities, why do you hang around? You just repeatedly make the point that "we do not know" and therefore.... what?
My bold

TooMany - Please do not question whether other people are "using their minds" nor their motivations for posting. Even if someone just wants to be a naysayer (and I am not saying Selfsim is doing so), that is completely their prerogative. If you do not wish to participate in such a discussion, then don't.

Everyone - Please make sure this discussion continues to be polite and non-personal.

Achilleus
2012-Dec-14, 02:23 PM
I have to ask why aliens would have to repeatedly visit earth to probe people, any advanced race would more than likely come to earth and abduct a few humans and take them back to their home planet and not have to make 100s or maybe 1000s of visits a year. Therefore I think the reports of people being abducted and then "let go" doesn't make sense to me. Also the idea of government covering up aliens gives too much credit to the world governments. Most cover ups end up coming uncovered pretty quickly. I.E. Kennedy, catholic church sex, etc

primummobile
2012-Dec-14, 02:42 PM
I have to ask why aliens would have to repeatedly visit earth to probe people, any advanced race would more than likely come to earth and abduct a few humans and take them back to their home planet and not have to make 100s or maybe 1000s of visits a year. Therefore I think the reports of people being abducted and then "let go" doesn't make sense to me. Also the idea of government covering up aliens gives too much credit to the world governments. Most cover ups end up coming uncovered pretty quickly. I.E. Kennedy, catholic church sex, etc

What Kennedy cover-up?

Achilleus
2012-Dec-14, 02:46 PM
The government tried to cover up the Kennedy assassination by saying Lee Harvey Oswald killed him with a single bullet, although proven physically impossible, then a few days later Lee Harvey Oswald gets shot, and then Oswald's assassin got rushed to death row to be killed
In the end it was one giant mess

PetersCreek
2012-Dec-14, 05:38 PM
What Kennedy cover-up?

Moderator comment: this is a little late considering the previous post but I'm going to say it anyway... Don't even go there. This thread is about aliens and any purported Kennedy cover-up not related to aliens is not an appropriate topic for this forum.

Swift
2012-Dec-14, 06:38 PM
The government tried to cover up the Kennedy assassination by saying Lee Harvey Oswald killed him with a single bullet, although proven physically impossible, then a few days later Lee Harvey Oswald gets shot, and then Oswald's assassin got rushed to death row to be killed
In the end it was one giant mess
Let me just add to what PetersCreek said - Achilleus - This means you. Conspiracy theories about the Kennedy assassination are not an acceptable topic ANYWHERE on CQ, and particularly not in Life In Space.

Gomar
2012-Dec-23, 03:23 AM
This thread is about aliens and any purported Kennedy cover-up not related to aliens is not an appropriate topic for this forum.

oh man, that's a bummer. I've always thought the two events were connected...
...by CSM ifcourse. [for those who've forgotten: CSM = Cigarette Smoking Man].

Noclevername
2012-Dec-23, 09:42 PM
You're making a call based on realism, when speaking of 'aliens'??

And you assume unrealism when speaking of aliens. So? Both points of view are based on the same observational evidence-- none.

We Don't Know.

MarianoRF
2013-Jan-02, 11:26 AM
expert says aliens dont exist

http://www.thesun.co.uk/sol/homepage/features/4631083/UFO-expert-Dr-David-Clarke-asks-whether-its-time-to-admit-aliens-dont-exist.html

ifcourse the white man did not exist until he landed in the New World and Australia.

Interesting point of view. And I ask: what if that article is true? What if we are completely alone? Because we simply have no evidence of life beyond Earth. Being the Universe so so vast and big, with billons of stars and galaxies, one would think that there's a very high amount of planets harboring life... but, do you ever considered this could be wrong? Maybe we are unique. Maybe Earth IS the special planet. Because you see, until we find some evidence of life beyond our planet, the fact is that WE are the only ones.

Paul Beardsley
2013-Jan-02, 11:35 AM
Interesting point of view. And I ask: what if that article is true? What if we are completely alone? Because we simply have no evidence of life beyond Earth. Being the Universe so so vast and big, with billons of stars and galaxies, one would think that there's a very high amount of planets harboring life... but, do you ever considered this could be wrong? Maybe we are unique. Maybe Earth IS the special planet. Because you see, until we find some evidence of life beyond our planet, the fact is that WE are the only ones.

We are certainly alone, but that's not the same thing, because it might be only temporary.

Of course it's possible that Earth is unique. The lack of any evidence is consistent with this. But then again, the lack of any evidence is also consistent with a universe teeming with life which for whatever reason hasn't visited us.

Both options, and everything in between, are interesting in their own right. For now, however, the only conclusion we can draw is that we simply don't know. It's surprising how many people have a problem with this conclusion.

MarianoRF
2013-Jan-02, 12:01 PM
Of course it's possible that Earth is unique. The lack of any evidence is consistent with this. But then again, the lack of any evidence is also consistent with a universe teeming with life which for whatever reason hasn't visited us.

Could be a temporary situation... or not. We'll have to wait.

Maybe life exists in a very distant planet/place, hundreds or even thousands of light-years away... how could we possibly detect it? Distances are so vast, so enormous that it's a real barrier for us to make observations/contact.

And besides, where to search for life? Universe has no boundaries, it's infinte, and there are no banners with "Start searching here". So, as far as I can see, detecting life beyond Earth, is really a big challenge.

Do you realize that maybe we will never observe/detect any ET-life form in our existance as human specie, due to these facts.