PDA

View Full Version : Copernican Fallacy & 'Numbers'



Selfsim
2012-Dec-22, 04:52 AM
So, some seem to think that we can invoke the Copernican Principle as the catalyst to infer the existence of exo-life, as it leads to a view that Earth is not ‘special’ or ‘privileged’. Earth contains life, therefore life will exist elsewhere in the universe, right? Extending this further, ‘the numbers’ of ‘Earth-like exo-planets’, implies that life will therefore be ‘likely’ within this population, yes?

Sounds logical, right?

The above argument is an attempted example of the Mediocrity Principle (http://en.wikipedia.org/wiki/Mediocrity_principle), which formally states that if an item is drawn at random from one of several sets (or categories), it's likelier to come from the most numerous category, rather than from any one of the less numerous categories. In other words: life is on Earth .. Earth is a random sample of a Copernican Principled Universe, thus via this principle, it is ‘likely’ there’ll be Earth-like life elsewhere.

Unfortunately, this attempt fails on several counts.

First of all, there is no knowledge about the characteristics of the population, (in this case the existence or non existence of life in the Universe). Secondly, the only sample comes from Earth which is not a random sample. Arguing that life on Earth supports the existence of life in the Universe, becomes a circular statement because the Mediocrity Principle has been reversed, and it is now claimed that the characteristic of the non-random sample, determines the dominating characteristic of the population, rather than the other way around.

The fallacy lies in the circular statement.

Even ignoring this fallacy, basing an argument on such reasoning, implies that the Mediocrity Principle, when applied correctly, is less likely than than the fallacious argument!

Solfe
2012-Dec-22, 05:17 AM
A serious question that I do not know the answer to:

Is there only one example of life on Earth? Could viral, eukarya, bacteria, and archaea be four examples of different types of life or are they definitively a single group?

Selfsim
2012-Dec-22, 05:51 AM
A serious question that I do not know the answer to:

Is there only one example of life on Earth? Could viral, eukarya, bacteria, and archaea be four examples of different types of life or are they definitively a single group?These are organisms: (http://en.wikipedia.org/wiki/Organism)


In biology, an organism is any contiguous living system (such as animal, fungus, micro-organism, or plant). In at least some form, all types of organisms are capable of response to stimuli, reproduction, growth and development and maintenance of homeostasis as a stable whole.They are classified as 'life'.
They all share a common biochemistry and genetic code: (http://en.wikipedia.org/wiki/Common_descent#Common_biochemistry_and_genetic_cod e)

All known forms of life are based on the same fundamental biochemical organisation: genetic information encoded in DNA, transcribed into RNA, through the effect of protein- and RNA-enzymes, then translated into proteins by (highly similar) ribosomes, with ATP, NADH and others as energy sources, etc.

Furthermore, the genetic code (the "translation table" according to which DNA information is translated into proteins) is nearly identical for all known lifeforms, from bacteria to humans. The universality of this code is generally regarded by biologists as definitive evidence in favor of the theory of universal common descent. Analysis of the small differences in the genetic code has also provided support for universal common descent. A statistical comparison of various alternative hypotheses has shown that universal common ancestry is significantly more probable than models involving multiple origins.
There are other lines of evidence such as Phylogenic trees, selectively neutral similarities, etc.

This is also somewhat off-topic.

Back to the Copernican Principle fallacious argument ...

Colin Robinson
2012-Dec-22, 07:07 AM
The above argument is an attempted example of the Mediocrity Principle (http://en.wikipedia.org/wiki/Mediocrity_principle), which formally states that if an item is drawn at random from one of several sets (or categories), it's likelier to come from the most numerous category, rather than from any one of the less numerous categories.

Looking at the WP page you've cited, the definition of the mediocrity principle which appears there comes from Andre Kukla, who also did the argument as to why the mediocrity principle can't be applied to the question of exterrestial life... As has recently been observed on its talk page (http://en.wikipedia.org/wiki/Talk:Mediocrity_principle), the WP article currently uses Andre Kukla so heavily that it almost reads like an ad for his book.

I'm not necessarily saying that Andre Kukla is wrong, but it might be interesting to compare his definition and treatment of the principle of mediocrity with those of others who do see it as relevant.

IsaacKuo
2012-Dec-22, 07:35 AM
This is a straw man argument. In fact, I think hardly anyone assumes that life is likely to evolve on Earth-like worlds based on the mediocrity principle alone.

The most famous tool for investigating the likely hood of alien life is the Drake equation, which explicitly includes a factor for what fraction of Earth-like worlds evolve life. Different users have different ideas on what's a plausible value to put there, and why, but I'm unaware of anybody who assigns a high value based purely on the mediocrity principle.

Instead, the typical thing is to apply some sort of reasoning based on working models of abiogenesis and/or panspermia, along with some sort of de facto Bayesian probability reasoning based on how quickly (or slowly, depending on one's perspective) life and/or intelligence showed up here on Earth. That includes me. Even though I am not a big fan of Bayesian probability reasoning, I can't deny that I'm essentially applying Bayesian reasoning when using the limited evidence available, out of necessity.

Note that if someone were actually arguing based the mediocrity principle alone, then he should believe that all Earth-like worlds evolve intelligent life. But people using the Drake equation typically assign some fractions to the latter terms, which is an admission of factors other than just the mediocrity principle.

Paul Beardsley
2012-Dec-22, 10:37 AM
This is a straw man argument. In fact, I think hardly anyone assumes that life is likely to evolve on Earth-like worlds based on the mediocrity principle alone.

A.DIM, a regular here, has repeatedly stated that the existence of alien life - and, indeed, visits to Earth by aliens - is not an extraordinary claim because of that principle. I don't know how typical he is.

I agree entirely with the OP, and I think people are overlooking the logical fallacies in their eagerness to "know" that we are not alone in the universe.

Reworking some of my recent observations on the subject, this is my take:

1. The existence of extraterrestrial life is consistent with what we think we know about the universe. However, we should have the humility to accept that we might be wrong about key issues, and until we have direct evidence of ET life, we cannot assume it exists.

2. The discovery of ET life should not surprise us. However, that is not the same as saying we should expect to find it. There's an obvious analogy for that, given the proximity of Christmas: Your exceedingly rich Uncle Harry likes you and he knows you want a sixty inch HD TV for Christmas. But you aren't going to know until Christmas morning if that's what you're going to get.

The thing that irritates me in advance is, if and when we do encounter alien life, there's going to be a bunch of people going, "We knew all along!"

IsaacKuo
2012-Dec-22, 11:22 AM
A.DIM, a regular here, has repeatedly stated that the existence of alien life - and, indeed, visits to Earth by aliens - is not an extraordinary claim because of that principle. I don't know how typical he is.
Actually, A. DIM believes that life originally came to Earth from beyond the solar system, rather than evolving here on Earth.

His thinking doesn't rely upon the mediocrity principle. His thinking relies upon arguments that abiogenesis is vanishingly unlikely. (I do not think these arguments are scientifically valid, and indeed they tend to be made by creationists, but we don't know enough about abiogenesis to rule out the possibility that it is impossible.)

I agree entirely with the OP, and I think people are overlooking the logical fallacies in their eagerness to "know" that we are not alone in the universe.
Perhaps, but not the specific straw man fallacy presented in the OP, I think.

Reworking some of my recent observations on the subject, this is my take:

1. The existence of extraterrestrial life is consistent with what we think we know about the universe. However, we should have the humility to accept that we might be wrong about key issues, and until we have direct evidence of ET life, we cannot assume it exists.
Sure, but we can presume that ET life is possible. It's wrong to think we have no evidence that alien life is possible. Our own existence is evidence in favor or the possibility of alien life. It's not absolutely conclusive. There might actually be something unique about Earth in the entire universe, which is a hard and fast pre-requisite for life.

But we shouldn't presume that there is something unique about Earth that makes life impossible everywhere else. That's not just a violation of the Copernican principle. It's magical thinking.

2. The discovery of ET life should not surprise us. However, that is not the same as saying we should expect to find it. There's an obvious analogy for that, given the proximity of Christmas: Your exceedingly rich Uncle Harry likes you and he knows you want a sixty inch HD TV for Christmas. But you aren't going to know until Christmas morning if that's what you're going to get.

The thing that irritates me in advance is, if and when we do encounter alien life, there's going to be a bunch of people going, "We knew all along!"
Well, there's going to be an even bigger bunch of people who shrug because they believe alien encounters have been quite commonplace all along.

grapes
2012-Dec-22, 11:53 AM
This is also somewhat off-topic.

Yes, but fascinating. I'd encourage Solfe to start a thread, and include your response. (And I will suggest my name for viral Eve: A1A1)

Paul Wally
2012-Dec-22, 12:52 PM
So, some seem to think that we can invoke the Copernican Principle as the catalyst to infer the existence of exo-life, as it leads to a view that Earth is not ‘special’ or ‘privileged’. Earth contains life, therefore life will exist elsewhere in the universe, right? Extending this further, ‘the numbers’ of ‘Earth-like exo-planets’, implies that life will therefore be ‘likely’ within this population, yes?

Sounds logical, right?

The above argument is an attempted example of the Mediocrity Principle (http://en.wikipedia.org/wiki/Mediocrity_principle), which formally states that if an item is drawn at random from one of several sets (or categories), it's likelier to come from the most numerous category, rather than from any one of the less numerous categories. In other words: life is on Earth .. Earth is a random sample of a Copernican Principled Universe, thus via this principle, it is ‘likely’ there’ll be Earth-like life elsewhere.

Unfortunately, this attempt fails on several counts.

First of all, there is no knowledge about the characteristics of the population, (in this case the existence or non existence of life in the Universe). Secondly, the only sample comes from Earth which is not a random sample. Arguing that life on Earth supports the existence of life in the Universe, becomes a circular statement because the Mediocrity Principle has been reversed, and it is now claimed that the characteristic of the non-random sample, determines the dominating characteristic of the population, rather than the other way around.

The fallacy lies in the circular statement.

Even ignoring this fallacy, basing an argument on such reasoning, implies that the Mediocrity Principle, when applied correctly, is less likely than than the fallacious argument!

What is the point of debating this exo-life exists/exo-life doesn't exist dichotomy of yours? Your ultimate conclusion is going to be that we don't know. We all know that we don't know, so really, what is the point?

With "point", I mean: What are the pragmatic implications of such a discussion? Because ultimately, from a pragmatic point of view it doesn't really matter what any of us believe or assume, but rather, what matters is how we should go about searching for the answer.

Glom
2012-Dec-22, 01:01 PM
Until we have a better understanding of how the abiogenesis happened, we cannot say how likely it is. If it is a 1 in a quadrillion chance, then the expectation of life throughout the universe is low.

How the abiogenesis occurs is a deep, interesting and sexy mystery. At the moment, too many are guilty of taking the lack of solution and plugging it with whatever takes their fancy.

eburacum45
2012-Dec-22, 02:39 PM
Until we have a better understanding of how the abiogenesis happened, we cannot say how likely it is.

We might never find out exactly how the particular abiogenesis event occured which gave rise to life on Earth. There could be multiple pathways each of which is as likely, or as unlikely, as the others. Even if we find evidence of similar, or dissimilar, abiogenesis events on other worlds we might not be able to determine the exact mechanism that gave rise to our biosphere.

Hornblower
2012-Dec-22, 03:02 PM
I don't see any great merit in invoking the Copernican Principle here. It says that the large scale properties of the cosmos are pretty much the same everywhere, and that the cosmos becomes more nearly homogeneous as we go to larger scales. It does not rule out the possibility that conditions needed for the emergence of lifeforms similar to ourselves are so exceedingly rare that there may not be another one within some billions of lightyears of us, if I am not mistaken.

Hlafordlaes
2012-Dec-22, 03:07 PM
For me:

Knowns:
0 < p(abiogenesis) < 1

Assumptions:
Abiogenesis is a natural process requiring no external agents.
Copernican: nothing special going on here on Earth.

Conclusions:
Abiogenesis happens. How is still a gap in our knowledge.

Take on ET life:
Conditions required for abiogenesis on Earth have been/are/will be present on many worlds, moons.
Abiogenesis will happen in 0 < n < all cases.

Take on confirmation:
This is the real ***** of the problem.

Solfe
2012-Dec-22, 03:11 PM
Selfsim and Grapes,

Thank you both, that information was great. I am going to do some reading and create a different thread.

Paul Wally
2012-Dec-22, 03:13 PM
I don't see any great merit in invoking the Copernican Principle here. It says that the large scale properties of the cosmos are pretty much the same everywhere, and that the cosmos becomes more nearly homogeneous as we go to larger scales. It does not rule out the possibility that conditions needed for the emergence of lifeforms similar to ourselves are so exceedingly rare that there may not be another one within some billions of lightyears of us, if I am not mistaken.

Yes, and even if the Copernican principle doesn't hold for some reason, that doesn't rule out the possibility that life is quite abundant. Why should we assume that the conditions that we know of are the only conditions conducive to the emergence of life?

Hornblower
2012-Dec-22, 03:45 PM
Yes, and even if the Copernican principle doesn't hold for some reason, that doesn't rule out the possibility that life is quite abundant. Why should we assume that the conditions that we know of are the only conditions conducive to the emergence of life?

My bold. I am not assuming any such thing. I was only speaking out against misapplication of a principle which, if I am not mistaken, does not address the details of small-scale things such as planets.

Suppose the Copernican Principle did not hold and there were major differences in the large-scale properties of cosmic regions billions of lightyears away. For all we know, those regions might be more favorable for the occurrence of advanced life forms.

My educated hunch, considering the observed abundance of planets and the observed occurrence of such substances as amino acids in deep space, is that there is a high probability that there are numerous advanced-life-bearing planets out there. The obstacles to communication, not to mention travel, are so formidable that it does not surprise me that intelligent beings out there have not made their presence known to us.

Paul Wally
2012-Dec-22, 03:55 PM
My bold. I am not assuming any such thing. I was only speaking out against misapplication of a principle which, if I am not mistaken, does not address the details of small-scale things such as planets.


Apology. I was only posing the question. My intention was not to imply that you made any assumption.

Colin Robinson
2012-Dec-22, 08:48 PM
A.DIM, a regular here, has repeatedly stated that the existence of alien life - and, indeed, visits to Earth by aliens - is not an extraordinary claim because of that principle. I don't know how typical he is.
I'm not A Dim and can't speak for him... I will say, however, that I don't see why the proposition that there is life beyond Earth is more "extraordinary" than the converse proposition – the proposition that life on Earth is a phenomenon without parallel elsewhere.

Nor do I see why Francis Crick's hypothesis that Earth was visited several billion years ago by interstellar travelers is any more "extraordinary", than the "Fermi-Hart Paradox" argument that says any technological civilization in the Milky Way galaxy would spread all over it and leave abundant evidence... Both those arguments clearly depend on interstellar travel being feasible... It may be feasible, it may not be...

Francis Crick (the discoverer of DNA) put forward his interstellar hypothesis because he doubted whether something as complex as DNA could have emerged spontaneously in the time available on ancient Earth... Recent analysis (e.g by Stuart Kauffman) suggests the contrary -- life could indeed have emerged spontaneously here, e.g. via autocatalytic sets...


What is the point of debating this exo-life exists/exo-life doesn't exist dichotomy of yours? Your ultimate conclusion is going to be that we don't know. We all know that we don't know, so really, what is the point?
With "point", I mean: What are the pragmatic implications of such a discussion? Because ultimately, from a pragmatic point of view it doesn't really matter what any of us believe or assume, but rather, what matters is how we should go about searching for the answer.

Exactly. A basic pragmatic question is whether or not policy-makers and the public should support the work of astrobiologists at NASA and other space agencies?

ASTRO BOY
2012-Dec-22, 09:21 PM
2. The discovery of ET life should not surprise us. However, that is not the same as saying we should expect to find it. There's an obvious analogy for that, given the proximity of Christmas: Your exceedingly rich Uncle Harry likes you and he knows you want a sixty inch HD TV for Christmas. But you aren't going to know until Christmas morning if that's what you're going to get.



The discovery of ET life Intelligent or otherwise certainly would not surprise me......I would be excited though...I mean I'm not dead yet!
But I do differ from [b] in that I do expect us to find it someday, and some are saying pretty soon. That would certainly make me happy before I kick the bucket, just as any astronomical/cosmological discovery has me excited.





The thing that irritates me in advance is, if and when we do encounter alien life, there's going to be a bunch of people going, "We knew all along!"

Apologies in advance for irratating you...:-)
But really, why would that irritate you?

ASTRO BOY
2012-Dec-22, 09:38 PM
I'm not A Dim and can't speak for him... I will say, however, that I don't see why the proposition that there is life beyond Earth is more "extraordinary" than the converse proposition – the proposition that life on Earth is a phenomenon without parallel elsewhere.




I'm only a layman but I would be far more surprised if it were shown that life did not exist anywhere off the Earth for many reasons I have given in other threads.
It also seems that most notable experts would agree with that.
But in reality could that logically ever happen?
I mean how big a region of the Universe would we need to explore/scan/examine to come to the assumption that life on Earth was a gigantic mistake and quirk of nature?
Considering the huge near infinite extent of the Universe.
In my opinion the only barrier to finding evidence for ET life off the Earth, is how diverse it really is...Would it be like finding a needle in a haystack?....Or a particular grain of sand on a beach?
Keeping in mind that some cosmologists number the stars in the observable Universe as more then all the grains of sand on all the beaches in the world...a large number.

Paul Beardsley
2012-Dec-22, 10:25 PM
I'm not A Dim and can't speak for him... I will say, however, that I don't see why the proposition that there is life beyond Earth is more "extraordinary" than the converse proposition – the proposition that life on Earth is a phenomenon without parallel elsewhere.

The extraordinary claim is to state with certainty that one proposition or the other is the correct one when the truth is, we don't know.

Why can't people accept "we don't know" at face value?

Why is urging caution repeatedly interpreted as arguing against the existence of ET life?

Claiming that ET is commonplace is an extraordinary claim. Claiming that we are alone in the universe is an extraordinary claim. Admitting that we don't know and won't know until we have new information is the only honest stance.

Paul Beardsley
2012-Dec-22, 10:39 PM
The discovery of ET life Intelligent or otherwise certainly would not surprise me......I would be excited though...I mean I'm not dead yet!

I am in agreement with this part. I would die happy if we could find conclusive evidence of microbes on Mars, let alone cities on Tau Ceti.


But I do differ from [b]

?


in that I do expect us to find it someday, and some are saying pretty soon.

Why? I mean, why, why, why? What possible reason can you have for expecting us to find it soon, other than it's what you want? Can't you even pretend we're talking science here?


Apologies in advance for irratating you...:-)

Too late.


But really, why would that irritate you?

Okay, here's an analogy. You have a pregnant friend who has decided not to find out the baby's gender until it's born. But you claim your magic coin can tell. You toss it and it comes up tails, and so you declare it's a boy. A bit later the baby is born and it's a boy. You take this as confirmation that the coin works. You're not joking, you really mean it, even though the coin got it wrong 50% of the time for the last 20 pregnant women.

ASTRO BOY
2012-Dec-22, 10:48 PM
The extraordinary claim is to state with certainty that one proposition or the other is the correct one when the truth is, we don't know.

Why can't people accept "we don't know" at face value?





I accept that as the nearest reality answer...always have.
But plain old common sense then steps in and due to many reasons, I, and many who are astronomers and cosmologists, see the need to conclude that we have a far better chance of ET existing then the alternative state.
That essentially maybe "opinionated" but as humans we are allowed to weigh up the circumstances and formulate a probable assumption based on known data.
I certainly don't accept your argument.

ASTRO BOY
2012-Dec-22, 10:56 PM
Why? I mean, why, why, why? What possible reason can you have for expecting us to find it soon, other than it's what you want? Can't you even pretend we're talking science here?

That's like asking 20 years ago why would we expect to find any extra solar planets.







Okay, here's an analogy. You have a pregnant friend who has decided not to find out the baby's gender until it's born. But you claim your magic coin can tell. You toss it and it comes up tails, and so you declare it's a boy. A bit later the baby is born and it's a boy. You take this as confirmation that the coin works. You're not joking, you really mean it, even though the coin got it wrong 50% of the time for the last 20 pregnant women.[/QUOTE]


LOL!
That supposed analogy does nothing for me and certainly has flaws.


But my original question remains....Why would that irritate you?

Paul Beardsley
2012-Dec-22, 11:03 PM
I accept that as the nearest reality answer...always have.
But plain old common sense then steps in

Common sense when you're up against the unknowns of the universe?


and due to many reasons, I, and many who are astronomers and cosmologists,

Appeal to authority noted.


see the need to conclude that we have a far better chance of ET existing then the alternative state.

I see the need but I recognise it as an emotional need.


That essentially maybe "opinionated" but as humans we are allowed to weigh up the circumstances and formulate a probable assumption based on known data.

Filling in the gaps is not data gathering.


I certainly don't accept your argument.

You cannot accept "we don't know" even though we don't know. And you wonder why that irritates me?

Paul Beardsley
2012-Dec-22, 11:21 PM
That's like asking 20 years ago why would we expect to find any extra solar planets.

It's more like going back 80 years to a time when "common sense" stated that extrasolar planets would be vanishingly rare because the prevailing theory was that planetary formation involved a close approach by another star. Back then, we didn't know if extrasolar planets existed. If anybody said, "So, do you think extrasolar planets are commonplace?" the only sensible answer would have been, "Current theory says no, but the truth is, we don't have any direct data to confirm this." A silly answer would have been, "No, there will be few or none because Sir James Jeans says so."



But my original question remains....Why would that irritate you?

Because coming up with the right answer for the wrong reason and then being smug about it is inherently irritating.

Selfsim
2012-Dec-22, 11:26 PM
What is the point of debating this exo-life exists/exo-life doesn't exist dichotomy of yours? Your ultimate conclusion is going to be that we don't know. We all know that we don't know, so really, what is the point? The point is that invoking the Copernican/Mediocirity Principle, and then using it in this way, to develop an argument in favour of exo-life, is fallacious.

I am simply answering the myriad of posts which have thrown this so-called 'logical' argument at me. (Including highly experienced members, who seem to be unaware of its implications).

Those who may have already trodden the path of threads similar to this one, should 'come out' and say they understand and agree, that the argument relies on a fallacy.

Why doesn't that frequently happen, come to think of it?


With "point", I mean: What are the pragmatic implications of such a discussion? Because ultimately, from a pragmatic point of view it doesn't really matter what any of us believe or assume, but rather, what matters is how we should go about searching for the answer.And yet, how often are these beliefs so closely held, as to become reality in the minds of those unaware of just how fallacious the argument really is, (as determined from the principles from which they're pitched)? The 'numbers' argument, is a natural flow-on, from the fallacy.

This is exactly where the 'filling in the blanks' approach, (ie: speculating), leads to, in this case.

I agree that exploration is a valid way to resolve the matter ... so why bother with the mediocrity argument in the first place?

Just skip it, and get to the action parts, (wherever its practically feasible that is ... of course).

ASTRO BOY
2012-Dec-22, 11:29 PM
Common sense when you're up against the unknowns of the universe?

Appeal to authority noted.



Great! You'll probably find many appeals to authority and experts from me to those at the cutting edge of all this stuff.
Being a layman I learn from these people and appreciate the knowledge they impart.



I see the need but I recognise it as an emotional need.



Not at all...Common sense based on numbers and observation just as the assumption re the homegenious and Isotropic state of the Universe.


[QUOTE=Paul Beardsley;2091577
You cannot accept "we don't know" even though we don't know. And you wonder why that irritates me?
[/QUOTE]


Sure I accept it...But the numbers involved then logically leave me to favour one alternative over the other, as it does many other experts in the field of astronomy and cosmology..

Regarding your irritation, I'll be over your way next year, so I'll try and alleviate that irritation by buying you a nice cold beer. :-)

Selfsim
2012-Dec-22, 11:37 PM
A.DIM, a regular here, has repeatedly stated that the existence of alien life - and, indeed, visits to Earth by aliens - is not an extraordinary claim because of that principle. I don't know how typical he is.
I'm not A Dim and can't speak for him... I will say, however, that I don't see why the proposition that there is life beyond Earth is more "extraordinary" than the converse proposition – the proposition that life on Earth is a phenomenon without parallel elsewhere.The Mediocrity Principle implicitly entails the Principle of Indifference, and its consequences. This approach, if applied consistently, leads nowhere in particular. (I suspect there is at least another person on this thread who already knows this).

Colin Robinson
2012-Dec-23, 12:03 AM
Someone who does argue on the basis of both the mediocrity principle and the anthropic principle — the cosmologist Alexander Valenkin of Tufts University. Some of his arguments are summarized in this article from Discover Magazine. (http://discovermagazine.com/1996/feb/themediocreunive694)

His inflationary cosmology involves multiple universes with different physical constants. Certain universes are more life-friendly than others: in some of them, life and intelligence cannot exist at all, in some there may be just one or two instances of intelligent life; in some there may be many.

Of course we don't know for certain that this many-universes model is right... However, if it is right, a question that arises is which of these classes of universe are we most probable to be living in?

That is the point where the argument arises about random choice of an element from multiple sets, where some sets containing many elements, some sets contain few, and some sets contain no elements at all...

Hlafordlaes
2012-Dec-23, 01:15 AM
First of all, there is no knowledge about the characteristics of the population, (in this case the existence or non existence of life in the Universe). Secondly, the only sample comes from Earth which is not a random sample. Arguing that life on Earth supports the existence of life in the Universe, becomes a circular statement because the Mediocrity Principle has been reversed, and it is now claimed that the characteristic of the non-random sample, determines the dominating characteristic of the population, rather than the other way around.

The fallacy lies in the circular statement.

Even ignoring this fallacy, basing an argument on such reasoning, implies that the Mediocrity Principle, when applied correctly, is less likely than than the fallacious argument!

Almost all of the science we do is based on the same single sample, yet from that we generalize universal laws. In a real sense, don't the results from much of astronomy confirm that much of the science done here on Earth does indeed apply elsewhere?

I cannot treat abiogenesis as anything other than a natural event, based on natural laws. Therefore I generalize it to be a possibility elsewhere, in much the same way I expect the physics in other systems to be the same as ours. The real fail right now is the inability to fully account for how abiogenesis works. Until then, the probabilities cannot be worked out.

Alternately, we may find a second example in our system, although I have a hunch it may form part of what becomes a local-to-our-system and now broader case, and leave the sample size at 1. This would be the case if early life was shared among planets via meteor exchange, for example, so that we are positing a single form of abiogenesis in the solar system.

ASTRO BOY
2012-Dec-23, 01:24 AM
Almost all of the science we do is based on the same single sample, yet from that we generalize universal laws. In a real sense, don't the results from much of astronomy confirm that much of the science done here on Earth does indeed apply elsewhere?

I cannot treat abiogenesis as anything other than a natural event, based on natural laws. Therefore I generalize it to be a possibility elsewhere, in much the same way I expect the physics in other systems to be the same as ours. The real fail right now is the inability to fully account for how abiogenesis works. Until then, the probabilities cannot be worked out.

Alternately, we may find a second example in our system, although I have a hunch it may form part of what becomes a local-to-our-system and now broader case, and leave the sample size at 1. This would be the case if early life was shared among planets via meteor exchange, for example, so that we are positing a single form of abiogenesis in the solar system.



Now that's pretty much hitting the nail right on the head!

I'm also a fan of "Panspermia"

Selfsim
2012-Dec-23, 01:31 AM
The most famous tool for investigating the likely hood of alien life is the Drake equation, which explicitly includes a factor for what fraction of Earth-like worlds evolve life. Different users have different ideas on what's a plausible value to put there, and why, but I'm unaware of anybody who assigns a high value based purely on the mediocrity principle.The fallacy persists, and is implicit in each successive estimation of each term of the Drake Equation, regardless of the reasons for selected probability assignments.

ASTRO BOY
2012-Dec-23, 01:39 AM
Because coming up with the right answer for the wrong reason and then being smug about it is inherently irritating.


That's your view....I have many logical reasons to believe as I do and as many much more learned then me believe in.
I'm not smug in the least.........You have many questions to answer to my satisfaction [and others] to change my thoughts and reasonings.

ASTRO BOY
2012-Dec-23, 01:52 AM
The fallacy persists, and is implicit in each successive estimation of each term of the Drake Equation, regardless of the reasons for selected probability assignments.



What fallacy?
What fallacy do we formulate the Cosmological principle on?

To put down and try and discredit a logical scientific assumption based on what we know as a "fallacy" is not really scientific.

Paul Wally
2012-Dec-23, 06:59 AM
I've always found the notion of "Earth as a sample size of one", a bit strange. For one, the Earth is an entire world with a rich variety biological phenomena. Certain abstracted aspects of life on Earth may be very well be quite representative of life in general, for example evolution and reproduction. Secondly, the notion suggests that statistical sampling is the only way to solve the abiogenesis problem, e.g. if we had say a sample of 1000 planets and moons, then we will be able to formulate a theory of abiogenesis. I think such an approach is highly ineffective and not to mention impractical. I think it is entirely possible to solve the abiogenesis problem theoretically.

Paul Beardsley
2012-Dec-23, 07:02 AM
Almost all of the science we do is based on the same single sample, yet from that we generalize universal laws. In a real sense, don't the results from much of astronomy confirm that much of the science done here on Earth does indeed apply elsewhere?

[My bold.]

Really? I would have said that we use a lot of data from other planets, from observations of other stars and galaxies, and through experiments on chemicals and subatomic particles where the only assumption is that they behave on Earth in the same way that they behave elsewhere in the universe.

This is very different from the "sample of one" where life arose (as far as we know) one time in one place, unwitnessed and not fully understood.


I cannot treat abiogenesis as anything other than a natural event, based on natural laws. Therefore I generalize it to be a possibility elsewhere, in much the same way I expect the physics in other systems to be the same as ours. The real fail right now is the inability to fully account for how abiogenesis works. Until then, the probabilities cannot be worked out.

I suspect this is the one thing we can all agree on. Does anybody not agree?

If we were to find direct evidence of life on other worlds, then that data could be used to help us understand how abiogenesis works. But we cannot do the reverse - we cannot use our incomplete understanding of abiogenesis to make assertions about the prevalence of alien life.


Alternately, we may find a second example in our system, although I have a hunch it may form part of what becomes a local-to-our-system and now broader case, and leave the sample size at 1. This would be the case if early life was shared among planets via meteor exchange, for example, so that we are positing a single form of abiogenesis in the solar system.

I'm not convinced by panspermia, but if we do find life on a planet where abiogenesis is unlikely to have occurred, I will just have to overcome my incredulity.

If we find life in the Europan ocean, I'd be inclined to think we have a sample size of 2, unless someone can explain how a meteorite got under the ice. If we find life unlike our own, I would also up the count of the sample size.

Paul Beardsley
2012-Dec-23, 07:09 AM
I've always found the notion of "Earth as a sample size of one", a bit strange. For one, the Earth is an entire world with a rich variety biological phenomena.

All of it related, all of it thought to have ultimately arisen from the same event. So there's nothing strange about calling it a sample size of one.


Certain abstracted aspects of life on Earth may be very well be quite representative of life in general, for example evolution and reproduction.

These things are more the definition of life than aspects of it.


Secondly, the notion suggests that statistical sampling is the only way to solve the abiogenesis problem, e.g. if we had say a sample of 1000 planets and moons, then we will be able to formulate a theory of abiogenesis. I think such an approach is highly ineffective and not to mention impractical. I think it is entirely possible to solve the abiogenesis problem theoretically.

Why did you even bother typing this when you could have used the time to present this theory? Why haven't you presented it now? Come on, we're waiting!

Selfsim
2012-Dec-23, 07:15 AM
Almost all of the science we do is based on the same single sample, yet from that we generalize universal laws. In a real sense, don't the results from much of astronomy confirm that much of the science done here on Earth does indeed apply elsewhere?

I cannot treat abiogenesis as anything other than a natural event, based on natural laws. Therefore I generalize it to be a possibility elsewhere, in much the same way I expect the physics in other systems to be the same as ours. The real fail right now is the inability to fully account for how abiogenesis works. Until then, the probabilities cannot be worked out.

Alternately, we may find a second example in our system, although I have a hunch it may form part of what becomes a local-to-our-system and now broader case, and leave the sample size at 1. This would be the case if early life was shared among planets via meteor exchange, for example, so that we are positing a single form of abiogenesis in the solar system.Everything which has ever reinforced the concept of universality of laws, has come from multitudes of empirical tests (both from Earth, and observations beyond). These observations are specifically why they become 'laws'.

No such universal laws can be formed for life outside of Earth, due to there being no external-to-Earth observations. (Also, absence of abiogenesis data).

How the laws of nature combine, to result in life anywhere, would be a law unto itself.

Why would we then assume this missing law to be equiprobable with laws confirmed to be universal, which result in planets, stars, gravity, etc?
We must be assuming they are equiprobable, because there is no reason to assume otherwise, other than there is no other choice, due to the absence of data.
Regarding them as equiprobable, is the principle of indifference and unfortunately, it turns out to be an invalid basis when applied to this topic, because it leads to conflicting probabilities.

Selfsim
2012-Dec-23, 07:33 AM
What fallacy?
What fallacy do we formulate the Cosmological principle on?

To put down and try and discredit a logical scientific assumption based on what we know as a "fallacy" is not really scientific.It is not the Copernican Principle that is the fallacy ... rather its application via the Mediocrity Principle to ET life.

The Copernican principle is perfectly consistent with physical cosmology in particular, the isotropic nature of the Universe.

Selfsim
2012-Dec-23, 07:45 AM
Note that if someone were actually arguing based the mediocrity principle alone, then he should believe that all Earth-like worlds evolve intelligent life. But people using the Drake equation typically assign some fractions to the latter terms, which is an admission of factors other than just the mediocrity principle.This statement doesn't follow.

The Mediocrity Principle attempts to address the existence of life on Earth-like planets, without being constrained to whether the life is intelligent or not. The Drake Equation on the other hand, only deals with intelligent life capable of interstellar communication.

At best, one can consider the output of the Drake equation as a subset of the Mediocrity Principle.

Colin Robinson
2012-Dec-23, 09:35 AM
If we were to find direct evidence of life on other worlds, then that data could be used to help us understand how abiogenesis works. But we cannot do the reverse - we cannot use our incomplete understanding of abiogenesis to make assertions about the prevalence of alien life.

Perhaps it depends what you mean by "assertions"...

A number of scientists who have worked on the question of abiogenesis, have presented reasoned arguments for thinking that life exists in many places through the universe. E.g. Christian de Duve, in an article in American Scientist, http://www.americanscientist.org/issues/id.864,y.0,no.,content.true,page.1,css.print/issue.aspx where he reaches the following conclusion:

"...life is an obligatory manifestation of matter, bound to arise where conditions are appropriate.... According to most experts who have considered the problem... there should be plenty of such sites, perhaps as many as one million per galaxy. If these experts are right, and if I am correct, there must be about as many foci of life in the universe. Life is a cosmic imperative. The universe is awash with life."

This is de Duve's professional opinion, based on reasons he presents... It doesn't put the question beyond dispute. On the other hand, it is not the same as just saying "don't know".

ASTRO BOY
2012-Dec-23, 09:36 AM
As far as aliens go, I suspect pretty strongly that there's life in space. We know of over 300 planets orbiting other stars, and we've only just started looking.
Phil Plait:
more.....
http://dsc.discovery.com/space/my-take/astronomer-alien-phil-plait.html

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Tom Foreman: You believe something is out there?

Seth Shostak: Oh, absolutely! The usual assumption is they're some sort of soft, squishy aliens like you see in the movies—just a little more advanced than we are so that we can find them. But the galaxy is two or three times that age, so there are going to be some societies out there that are millions of years, maybe more, beyond ours. So they may have proceeded beyond biology—maybe they've invented thinking machines and it could be that what we first find is something that's artificially constructed.


more...
http://news.nationalgeographic.com.au/news/2003/03/0331_030401_setishostak.html

Others that come to mind immediately are Carl Sagan, Paul Davis Michio Kaku, Stephen Hawking, Brian Green, Kip Thorne, Karl Kruszelnicki, Mitch Begalman, Sir Martin Rees...........Those are just a few whose books I have read, and/or whose comments I have heard about the existence of ET life, all while accepting that we have no direct evidence, but all at the same time knowing the numbers and extent of space/time that makes that situation far more likely then non existence.

And yes I am able to make up my own mind and have done that probably for the same reason as the above mentioned scientists.
While there is a non zero chance of no ET life, there is a far greater chance that there is.
I'm sticking with the odds.

Paul Wally
2012-Dec-23, 10:30 AM
All of it related, all of it thought to have ultimately arisen from the same event.
... or from the same process. Similar processes might have occurred elsewhere also. The problem is to understand the nature of such processes.


So there's nothing strange about calling it a sample size of one.

Well, calling it a sample size of one suggests that the plan is to gather statistics from a sufficiently large number of planets with life on them. Do you really think that is the most effective way to understand how life emerges? We have learned about stars by studying the sun, a single sample. We've figured out how the sun burns through a process of nuclear fusion, we've figured out what solar flares and sunspots are and we explain their existence. All that by studying one sample. We pretty certain that these same processes occur in other stars. Scientists didn't say that we only have a sample size of one star with solar flares, we need more samples of other stars with solar flares in order to understand how solar flares emerge from the sun. I think that's just silly, just as it is silly to suggest we need more samples of other planets with life in order to figure out how abiogenesis happens.



Why did you even bother typing this when you could have used the time to present this theory? Why haven't you presented it now? Come on, we're waiting!

I didn't say that I have such a theory, only that I think such a theory is possible, and I want to add that I also think such a theory is possible without having to discover any other 'samples' than the one we have.

Paul Beardsley
2012-Dec-23, 03:23 PM
Well, calling it a sample size of one suggests that the plan is to gather statistics from a sufficiently large number of planets with life on them.

No. Calling it a sample size of one is an accurate description of what we have. It says nothing about intent. The sample size of one gets mentioned a lot because people persist in drawing conclusions that cannot be drawn from a small sample, let alone a sample of one.


Do you really think that is the most effective way to understand how life emerges? We have learned about stars by studying the sun, a single sample. We've figured out how the sun burns through a process of nuclear fusion, we've figured out what solar flares and sunspots are and we explain their existence. All that by studying one sample. We pretty certain that these same processes occur in other stars. Scientists didn't say that we only have a sample size of one star with solar flares, we need more samples of other stars with solar flares in order to understand how solar flares emerge from the sun. I think that's just silly, just as it is silly to suggest we need more samples of other planets with life in order to figure out how abiogenesis happens.

Thanks to spectroscopy, we know what the Sun is made of, and we know what other stars are made of. We are able to duplicate the nuclear fusion process here on Earth.

Life in space is spectacularly not equivalent. We don't have direct observation of life on other worlds, and we aren't able to duplicate the process of abiogenesis here on Earth, not even as a computer similation, as far as I know.


I didn't say that I have such a theory, only that I think such a theory is possible, and I want to add that I also think such a theory is possible without having to discover any other 'samples' than the one we have.

If someone can explain how abiogenesis happened, then great - that would, as I say, be the equivalent of knowing how nuclear fusion works when it comes to explaining how stars shine. But just thinking someone will come up with an explanation is not going to advance anything.

swampyankee
2012-Dec-23, 04:41 PM
I don't think that the mediocrity principle, itself, is fallacious, but that there are people who are extrapolating its applicability far beyond the laws of nature. While these are, by every possible test, invariant across the Universe, this does not imply that the processes that result in life are inevitable, given the correct conditions.

The Copernican Principle does not say Earth is not somehow special, as it obviously is: we're here, for one thing, not anyplace else, it says that the laws of nature on Earth are not special.

As a somewhat more immediate example: all humans have the same biology, but every human is distinct in some way. The same biology produced Albert Einstein and Uri Geller.

Noclevername
2012-Dec-23, 05:18 PM
Claiming that ET is commonplace is an extraordinary claim. Claiming that we are alone in the universe is an extraordinary claim. Admitting that we don't know and won't know until we have new information is the only honest stance.

100% true. And true of the median between those extremes as well.

But we're getting new information all the time. No, it's not discovery of life, but it tells us some things about how the universe operates, which is what life is based on. That forms a basis for speculation.

Hlafordlaes
2012-Dec-23, 06:18 PM
Really? I would have said that we use a lot of data from other planets, from observations of other stars and galaxies, and through experiments on chemicals and subatomic particles where the only assumption is that they behave on Earth in the same way that they behave elsewhere in the universe.

I was referring to all of science, not just astronomy, but OK.


If we were to find direct evidence of life on other worlds, then that data could be used to help us understand how abiogenesis works. But we cannot do the reverse - we cannot use our incomplete understanding of abiogenesis to make assertions about the prevalence of alien life.

Agreed, an incomplete understanding does not allow assigning probabilities. Only possibilities.


I'm not convinced by panspermia, but if we do find life on a planet where abiogenesis is unlikely to have occurred, I will just have to overcome my incredulity. If we find life in the Europan ocean, I'd be inclined to think we have a sample size of 2, unless someone can explain how a meteorite got under the ice. If we find life unlike our own, I would also up the count of the sample size.

Kind of sorry I threw panspermia into it. I'm not heavily invested in it one way or another; I am currently "under the influence" of the notion that the projections for life elsewhere in our system made on the basis of Earth's extremophiles may be misguided, as extremophiles on Earth may represent migrations post-abiogenesis more than indications of where/how life emerges. Emotionally, if you will, I am still rooting for finding sample 2 somewhere around town.


Everything which has ever reinforced the concept of universality of laws, has come from multitudes of empirical tests (both from Earth, and observations beyond). These observations are specifically why they become 'laws'.

No such universal laws can be formed for life outside of Earth, due to there being no external-to-Earth observations. (Also, absence of abiogenesis data).

How the laws of nature combine, to result in life anywhere, would be a law unto itself.

Why would we then assume this missing law to be equiprobable with laws confirmed to be universal, which result in planets, stars, gravity, etc?
We must be assuming they are equiprobable, because there is no reason to assume otherwise, other than there is no other choice, due to the absence of data.
Regarding them as equiprobable, is the principle of indifference and unfortunately, it turns out to be an invalid basis when applied to this topic, because it leads to conflicting probabilities.

I would assume the undiscovered laws governing abiogenesis to be completely similar in nature to any other laws governing physics and chemistry, and to share the same universality. What I sincerely doubt is that we will find any conditions in any of Earth's history that make the planet a truly unique case in the universe, a true sample of 1. So far, nothing at all indicates we are, and if life itself is to be that proof, we'd need to disprove it exists anywhere else, no?

Selfsim
2012-Dec-23, 09:08 PM
I would assume the undiscovered laws governing abiogenesis to be completely similar in nature to any other laws governing physics and chemistry, and to share the same universality. And I think that's what I was trying to get at. Ie: this is a key assumption, with a fallacious basis, which drives the expectation in a particular direction ... nothing more.

Although the concept of universality of Laws purports to encompass everything known, and at times, they might seem to come very close to it, in many cases, we're also aware of their limits of applicability.

There's always a chance that data can render Laws to not be as universally applicable inside their respective domains, as we initially thought. If this is accepted, then there must be a finite probability within that domain that they aren't universal. Across the spread of all known Laws, there would be differences in the size of the domains of applicability. So, why would we assume a 'universal' Law of life mimics another its degree of applicability? If we assume that it does, (as you said above), then that's something we've assumed .. all on the basis of no evidence for making that assumption.

I think this is just another way we've sort of 'tricked' ourselves into believing that there 'must' be a sole causal connection between the Laws of Physics and Chemistry and the emergence of life. We know that modern life is complex. That means that the sum of the constituents, does not add up to the whole. Why should we assume that the Laws of Physics and Chemistry add up to the whole of life, when it comes to emergence? If it did, surely we'd have biochemists everywhere, mixing up life from scratch, in the lab!


What I sincerely doubt is that we will find any conditions in any of Earth's history that make the planet a truly unique case in the universe, a true sample of 1. It is not possible to 'postdict' in all levels of detail, at all levels of scale, in order to recreate emergence conditions.

We know Evolution for instance, is non-linear and punctuated by randomness. This is the barrier to postdiction. We may try and generalise certain conditions to overcome this, (and, somewhat improperly in a formal sense), seek 'evidence' to convince ourselves we can overcome it, but this then introduces uncertainty, and diminishes the ability to pre(post)dict with precision, (and maybe even, at levels of absolute relevance to emergence of it).


So far, nothing at all indicates we are, and if life itself is to be that proof, we'd need to disprove it exists anywhere else, no?And no matter how extensive and complete the search may be, the possibility would always remain that it was not complete enough, or not in the right place at the right times, the correct SETI frequencies, the right technologies, etc. There are countless variables which could impact the completeness of such searches, also. There will always be residual chances that undetected aliens are still out there.

Our tests need to be capable of ruling out false positives and false negatives .. (and they aren't .... remote tests certainly aren't).

In a way, success and failure, (in terms of detection/no detection), aren't the expected outcomes of such a search, at all. The outcomes are really: (i) 'success', (a fluke life discovery) and; (ii) 'no resolution at all'.

So, if directed searches are prone to this fundamental issue, then why bother with directed searches at all? We might as well just get out there and start snooping around .. that stands about as good a chance as directed searches of finding something … y'know(??)

Noclevername
2012-Dec-23, 09:36 PM
Our tests need to be capable of ruling out false positives and false negatives .. (and they aren't .... remote tests certainly aren't).

In a way, success and failure, (in terms of detection/no detection), aren't the expected outcomes of such a search, at all. The outcomes are really: (i) 'success', (a fluke life discovery) and; (ii) 'no resolution at all'.

So, if directed searches are prone to this fundamental issue, then why bother with directed searches at all? We might as well just get out there and start snooping around .. that stands about as good a chance as directed searches of finding something … y'know(??)

Random really has as much chance as directed? I'm not sure I agree with that conclusion (though getting out there and snooping would be a good thing).

Since most of Out There consists of places we can't go yet and since our science budgets are limited, we need some parameters to our search, and the needs of life-as-we-know-it make for pretty good ones.

Colin Robinson
2012-Dec-23, 10:06 PM
If someone can explain how abiogenesis happened, then great - that would, as I say, be the equivalent of knowing how nuclear fusion works when it comes to explaining how stars shine.

Excellent scientific minds are working on it... There are links to some of the latest papers in the thread about autocatalysis, and in other recent abiogenesis threads in this forum.

Selfsim
2012-Dec-23, 10:42 PM
Excellent scientific minds are working on it... There are links to some of the latest papers in the thread about autocatalysis, and in other recent abiogenesis threads in this forum.The quality of 'the minds', is not the issue. That those minds have ideas and opinions, just like the rest of us, is also not the issue.

Recognition of: that logically fallacious assumptions can be shown to be at the heart of what then gets wrapped up in further logical argumentation, demonstrates a major inconsistency in the use of logic itself. If an argument is shown to be fallacious, using the very same logic which forms it, then the argument should be abandoned, as it has been exposed as being false.

If the same inconsistency was evident in the solution to a maths problem, the answer would simply be "incorrect".

In spite of the exposition, further sustained and tenacious attachment to an exposed argument, infers other motivation.

I am pretty much convinced this is exactly what will persist here. Prove me wrong.

Selfsim
2012-Dec-23, 11:15 PM
Say there’s 3 planets in a universe: A, B and C, and there is complete uncertainty about any of these containing life. Eliminating 'complete unknowns', (presuming we know how to do this and just for the sake of the discussion), the possible scenarios are:

1) A and B contain life
2) Neither A nor B contain life
3) A contains life, B doesn’t
4) B contains life, but A doesn’t.

Applying the Principle of Indifference, (in the light of there being zero data), the probability for the hypothesis that there are more life-bearing planets, than non-life bearing planets is 3/4. But complete uncertainty requires us to be indifferent to options (1) and (2) above.

Applying the principle of Indifference to this particular set, results in a probability of 1/2 for the hypothesis that there is life on other planets!

So, the Principle of Indifference leads us to a probability of 1/2 'that there is life on other planets', is identical to the 3/4 probability 'that there are more life-bearing, than non-life bearing planets' ... which is impossible.

If this principle is to be used, (and it has inside the OP Mediocrity based argument), then 'typicalness' has to have come from somewhere other than 'the numbers'.

Ie: 'the numbers' argument (relating 'the likelihood' of life, to 'the numbers' of Earth-like 'worlds'), holds no meaning, and is shown here, to also be fallacious.

Selfsim
2012-Dec-23, 11:25 PM
So far, we have: an argument presented from one of the fundamental principles of Astrophysical science, (the Copernican Principle). The argument for the ‘likelihood’ of ET life, relies on this principle, and distinguishes the Mediocrity Principle, in so doing.

A fallacy appears.

This fallacy stems from another logical principle, called the ‘Principle of Indifference’, (which I mentioned several posts ago). This principle is not an effective basis for discussion about ET.

Post #53 demonstrates why.

Colin Robinson
2012-Dec-23, 11:52 PM
Say there’s 3 planets in a universe: A, B and C, and there is complete uncertainty about any of these containing life. Eliminating 'complete unknowns', (presuming we know how to do this and just for the sake of the discussion), the possible scenarios are:

1) A and B contain life
2) Neither A nor B contain life
3) A contains life, B doesn’t
4) B contains life, but A doesn’t.

You've mentioned 3 planets, A, B, and C... Then you've given us 4 possible scenarios about planets A and B... So what happened to C? Has it fallen thru a black hole into a parallel universe?


Applying the Principle of Indifference, (in the light of there being zero data), the probability for the hypothesis that there are more life-bearing planets, than non-life bearing planets is 3/4.

? Of the 4 scenarios you've mentioned,

(1) Number of life-bearing planets = 2. Number of non-life-bearing = 0
(2) Number of life-bearing planets = 0. Number of non-life-bearing = 2
(3) Number of life-bearing planets = 1. Number of non-life-bearing = 1
(4) Number of life-bearing planets = 1. Number of non-life-bearing = 1

So why do you say that, "the probability for the hypothesis that there are more life-bearing planets, than non-life bearing planets is 3/4"??

Unless planet C just came back again thru that wormhole?


Ie: 'the numbers' argument (relating 'the likelihood' of life, to 'the numbers' of Earth-like 'worlds'), holds no meaning, and is shown here, to also be fallacious.

If you want to prove something fallacious, you'll need to present a clear, rigorous argument — one that doesn't contain fallacies of its own... I'm afraid what you've given us does not qualify.

Selfsim
2012-Dec-24, 12:10 AM
A cheap shot?

I concede an obvious typo … nothing else.

Hlafordlaes
2012-Dec-24, 02:45 PM
In spite of the exposition, further sustained and tenacious attachment to an exposed argument, infers other motivation.

Unfortunately, Sunday posting is competing with NFL games (go Redskins!), so I have been remiss in groking this Indifference issue. But I'll be trying to work it thru during the week if real life abates in its hectic pace. Just want to have fun thinking and maybe learning; no other motivations. Don't despair, life's never fair, especially online!

Paul Wally
2012-Dec-24, 03:20 PM
So, if directed searches are prone to this fundamental issue, then why bother with directed searches at all? We might as well just get out there and start snooping around .. that stands about as good a chance as directed searches of finding something … y'know(??)

My bold

Do you have some kind of mathematical proof for that assertion? I'm pretty sure that making use of prior knowledge (clues) would increase our chances of finding something. So you're saying that we should just ignore everything we already know and just snoop around randomly. How about starting with the sun and work our way towards the Oort cloud, or shouldn't it be done in any particular order? Or how about putting the names of a list of planets and moons in a big bowl and drawing one randomly. That way we can randomize where to send the next billion dollar probe.

Frank Merton
2012-Dec-24, 05:27 PM
First I think abiogenesis is a near certainty given a reducing atmosphere, energy sources, a huge ocean and billions of years. Who knows what sort of soup such a world would cook up.

Given that, it also seems likely that it has happened many places.

But now we run into a few problems. What protects these worlds from exterminating disasters, which probably can be expected at least every few hundred million years? Then there is the rise of complex life as opposed to self-replicating molecules. That seems to hinge on more difficult factors.

All things considered, however, I am inclined to say one should side with Copernicus. So many tries to make us the center of things have failed. As they say in the stock market, "The trend is your friend."

Colin Robinson
2012-Dec-24, 05:46 PM
So, if directed searches are prone to this fundamental issue, then why bother with directed searches at all? We might as well just get out there and start snooping around .. that stands about as good a chance as directed searches of finding something … y'know(??)My bold

Do you have some kind of mathematical proof for that assertion? I'm pretty sure that making use of prior knowledge (clues) would increase our chances of finding something. So you're saying that we should just ignore everything we already know and just snoop around randomly. How about starting with the sun and work our way towards the Oort cloud, or shouldn't it be done in any particular order? Or how about putting the names of a list of planets and moons in a big bowl and drawing one randomly. That way we can randomize where to send the next billion dollar probe.

I'd agree that a totally random search of the solar system would not be the way to go.

On the other hand, I agree to a certain extent with Selfsim — I think it is possible for a search for life to be too directed, a mistake that was made by Viking.

The Viking mission tried to look for direct evidence of life in Mars sand, at a time when we didn't yet know what sort of minerals Mars sand contained — it was rather like looking for a needle in a haystack when you don't yet know what sort of hay you are dealing with, and nor do you know what sort of needle might or might not be there...

The result of Viking was that premature negative conclusions were drawn by scientists including Norman Horowitz. He concluded that almost certainly the family of Earth biota is alone in this solar system, and that was at a time when no extra-solar planets had yet been found...

Perhaps that is the difference between Viking and Curiosity. Viking was looking for direct smoking-gun evidence. Curiosity is looking for general clues. Which is less exciting, in a way, but probably more sensible...

Selfsim
2012-Dec-24, 08:58 PM
​So, if directed searches are prone to this fundamental issue, then why bother with directed searches at all? We might as well just get out there and start snooping around .. that stands about as good a chance as directed searches of finding something … y'know(??)My bold

Do you have some kind of mathematical proof for that assertion? Ok, so rather than backtrack through the entire thread, let's start from from the summary in post#54. (http://cosmoquest.org/forum/showthread.php/140478-Copernican-Fallacy-amp-Numbers?p=2091824#post2091824)

The Principle of Indifference (POI), via the Copernican and Mediocrity Principles, is what led to this issue. So, from the example in post #53, (http://cosmoquest.org/forum/showthread.php/140478-Copernican-Fallacy-amp-Numbers?p=2091823#post2091823) (containing the notorious editing error :) ), two conflicting probability figures result: 3/4 and 1/2.

Continuing with the POI, one could also argue indifference to anything which may have some bearing on the 'truth', or otherwise, of the existence ET life, including whether or not Earth and its evolution is 'special' or 'typical', also. The POI leads ultimately to a 'pure' probability of 1/2 which, when one thinks about it, ain't bad odds, eh? (Ie: Good enough to warrant exploration expenditures!)

ET believers might as well leap-frog the Mediocrity Principle and go straight to the POI .. which would make the whole Mediocrity Principle basis, moot. (Which I think, was your original point*).

There are no pure logical factors, including: 'the numbers', or 'the maths', which would underwrite either the 'for' or 'against' arguments. There are no arguments for having any opinions at all! (Which is also where the current data leaves us .. or even, arguably, where the current interpretive theoretical bases combined with the current data, leaves us).


I'm pretty sure that making use of prior knowledge (clues) would increase our chances of finding something.See, again, continuing the MP/POI argument, (albeit being flawed when attempting to apply it for arguing 'for or 'against'), one should also approach 'the evidence' (or more appropriately, 'the data'), consistently, from the same Principle of Indifference basis, (arrived at from the Copernican Principle).


So you're saying that we should just ignore everything we already know and just snoop around randomly. .. or snoop around in a locale, where the technology of our current tests, can be demonstrated to permit containment of the uncertainties, known to result in false positives, or false negatives.

Nothing else seems to align better with the key guiding principle of Astronomical research (ie: the CP) .. (??)


How about starting with the sun and work our way towards the Oort cloud, or shouldn't it be done in any particular order? Or how about putting the names of a list of planets and moons in a big bowl and drawing one randomly. That way we can randomize where to send the next billion dollar probe.

The exploration of our System should not be driven by a search for life. There is no logical basis for doing so, although, this doesn't of course, rule out the possibility of a chance discovery of it.

{Aside: As a demonstration of the tests which could be applied from this strategy: Will a billion dollars take us to the (hypothesised) Oort Cloud, and will such a project allow us to eliminate, to a reasonable extent, the testing uncertainties known to lead to false positives and false negatives?}

* Footnote: I have been pummelled, in the past, by Copernican Principled (CP) 'exo-lifers', who argue the 'strawman' argument presented in my OP. This argument has been shown herein, to have been fallaciously applied by those LIS forum posters. This thread serves as my 'right of reply' to such posters.

Selfsim
2012-Dec-24, 09:29 PM
Unfortunately, Sunday posting is competing with NFL games (go Redskins!),Go for it!

Happy Christmas …. both to yourself … and all!

so I have been remiss in groking this Indifference issue."Grokking"?? :( :doh:

...life's never fair, especially onlineEspecially when sci-fi 'lingo' is invading the Webster's and Oxford English Dictionaries. :doh:
:p :)

Cheers

Glom
2012-Dec-24, 09:30 PM
Viking was hardly thorough though. What did it do that Curiosity doesn't? If there is a smoking gun to be found Curiosity will find it.

The lack of any smoking gun so far, from Curiosity, Spirit, Oppy and others can certainly be used to say Mars never teamed with life, even primitive life.

To a slightly different point: Where exactly does self-replicating molecules end and life begin?

Selfsim
2012-Dec-24, 10:26 PM
Viking was hardly thorough though. What did it do that Curiosity doesn't? If there is a smoking gun to be found Curiosity will find it.

The lack of any smoking gun so far, from Curiosity, Spirit, Oppy and others can certainly be used to say Mars never teamed with life, even primitive life.What exactly is the 'smoking gun'?

Can we prescribe Mars', in advance of finding it?

How?

After all, guns were made by humans … on Earth.



To a slightly different point: Where exactly does self-replicating molecules end and life begin?Same question ... how can we prescribe this, in advance of discovering it, say, in the case of Mars?

Colin Robinson
2012-Dec-25, 01:29 AM
There are no pure logical factors, including: 'the numbers', or 'the maths', which would underwrite either the 'for' or 'against' arguments. There are no arguments for having any opinions at all! (Which is also where the current data leaves us .. or even, arguably, where the current interpretive theoretical bases combined with the current data, leaves us).

If we really didn't know anything at all about the possible existence, possible amount and possible complexity of life on other planetary bodies, then I think words like "indifferent" and "random" would be quite appropriate to the comparison between life there and life here.

Take Mercury, for instance. If we knew nothing at all that was relevant to existence or non-existence of life on Mercury, but were curious about the question, then we would need to consider at least three possibilities.

* Mercury has less life than Earth, perhaps none at all.
* Life on Mercury is equally abundant as life on Earth.
* Life on Mercury is more abundant than life on Earth, perhaps much more abundant.

In fact, however, we do know quite a lot about Mercury — enough to make the existence of any sort of life there seem highly implausible...

Or is that only an "opinion"? Is it perhaps the sort of "opinion" you have in mind when you say "There are no arguments for having any opinions at all! " ?


I have been pummelled, in the past, by Copernican Principled (CP) 'exo-lifers', who argue the 'strawman' argument presented in my OP. This argument has been shown herein, to have been fallaciously applied by those LIS forum posters. This thread serves as my 'right of reply' to such posters.

Not sure what you mean by "pummeled"? Does emphatic disagreement constitute "pummeling"? Do you see your own comments — in this thread and others — as a retaliatory "pummel"?

Selfsim
2012-Dec-25, 01:34 AM
See, the problem is that the search for ET, in scientific terms, is a test for our present model of universal life.

The idea that the search is about looking specifically for an exact replica of Earth-like life, stands a chance of failing by; (i) not detecting a different type of exo-life, or; (ii) concluding that exo-environmental conditions result in Earth-like life, before we know that, and then excluding non-Earth-like planets.

Ie it makes the error of presuming in advance, an unstated assumption about unsupportable frequencies of occurrence, and types of life, and then it gets even worse, by specifically selecting a preferred sample of: 'Earth-like' planets. It also makes the assumption that Earth-like planets cause Earth-like life. (Which is entirely opinion dependent, subject to various wobbly hypotheses, and has zero supporting data).

Searching to test a universal model of life however, is a different kettle of fish, because it makes no presumptions about the 'specific-ness', (specificity), because it is based on what is presently known and established via scientific testing. Sure, Earth-like life might turn up, but the difference is all about the tests derived from the idea that our known life model, might be universal. Tests based on this premise, would not specifically target Earth-like planets (although, they would be included) … it could also encompass non-Earth-like planets in our local neighbourhood, or synthetic lab developed life, or ETs visiting us, or ETs calling us up. All this requires no presumed inferences, which can lead to exactly the same fallacy described in the OP argument.

Frank Merton
2012-Dec-25, 01:54 AM
To a slightly different point: Where exactly does self-replicating molecules end and life begin?
Self-replicating molecules eventually exhaust the available stuff for replication (food). Then the molecules have to either compete for food or eat each other. Either way natural selection and evolution begins and you have life.

Frank Merton
2012-Dec-25, 02:01 AM
In fact, however, we do know quite a lot about Mercury — enough to make the existence of any sort of life there seem highly implausible...Herschel Sr. thought there was life on the sun. We have moved from seeing life everywhere to an awareness that, in spite of its adaptability, it is actually fragile.

There is often talk (I would call it uninformed and glib) about life based on things other than carbon chain molecules (which required liquid water and a limited range of temperatures). None seem reasonable.

So our best bet is to go with the water.

Colin Robinson
2012-Dec-25, 04:37 AM
See, the problem is that the search for ET, in scientific terms, is a test for our present model of universal life.

The idea that the search is about looking specifically for an exact replica of Earth-like life, stands a chance of failing by; (i) not detecting a different type of exo-life, or; (ii) concluding that exo-environmental conditions result in Earth-like life, before we know that, and then excluding non-Earth-like planets.

Ie it makes the error of presuming in advance, an unstated assumption about unsupportable frequencies of occurrence, and types of life, and then it gets even worse, by specifically selecting a preferred sample of: 'Earth-like' planets. It also makes the assumption that Earth-like planets cause Earth-like life. (Which is entirely opinion dependent, subject to various wobbly hypotheses, and has zero supporting data).

Searching to test a universal model of life however, is a different kettle of fish, because it makes no presumptions about the 'specific-ness', (specificity), because it is based on what is presently known and established via scientific testing. Sure, Earth-like life might turn up, but the difference is all about the tests derived from the idea that our known life model, might be universal. Tests based on this premise, would not specifically target Earth-like planets (although, they would be included) … it could also encompass non-Earth-like planets in our local neighbourhood, or synthetic lab developed life, or ETs visiting us, or ETs calling us up. All this requires no presumed inferences, which can lead to exactly the same fallacy described in the OP argument.

I agree that it is important to consider possibilities of life that are not Earth-like, and to study planets and moons that differ in various ways from our own planet. I am not sure what it is meant by "presumed inferences", nor am I convinced that the so-called fallacy mentioned in the OP is a fallacy at all.

Colin Robinson
2012-Dec-25, 04:58 AM
Herschel Sr. thought there was life on the sun. We have moved from seeing life everywhere to an awareness that, in spite of its adaptability, it is actually fragile.

Perhaps that means that, whatever the limits of our knowledge, we do know more both about life sciences and about the universe than in Herschel Sr's time... Astrobiology is becoming more feasible.


There is often talk (I would call it uninformed and glib) about life based on things other than carbon chain molecules (which required liquid water and a limited range of temperatures). None seem reasonable.

Well, it is not self-evident that life based on carbon-chain molecules requires liquid water as a solvent...

We've discussed this question in other threads. For instance the thread Life on Titan: would it be Earth-like enough to detect? (http://cosmoquest.org/forum/showthread.php/139043-Life-on-Titan-would-it-be-Earth-like-enough-to-detect)

Paul Beardsley
2012-Dec-25, 05:26 AM
All things considered, however, I am inclined to say one should side with Copernicus. So many tries to make us the center of things have failed. As they say in the stock market, "The trend is your friend."

I think this pushes the discussion back to square one. Why assume Earth is the trend when we have only one example of that sort of planet? Why not assume that the universe is dominated by Venus-like runaway greenhouses? Doesn't it occur to you that making life - i.e. stuff like us - commonplace is simply another attempt to put us at the centre of the universe again?

Not that attempts to put us at the centre has any effect on what the real universe is doing.

Paul Beardsley
2012-Dec-25, 05:34 AM
Perhaps that means that, whatever the limits of our knowledge, we do know more both about life sciences and about the universe than in Herschel Sr's time... Astrobiology is becoming more feasible.

Obviously our knowledge has advanced. Now, we can point at certain locations (the Europan ocean, for instance) and say, "I would not be at all surprised to find life there," and we can point at other locations (Mercury, for instance) and say, "I would be very surprised to find life there."

Colin Robinson
2012-Dec-25, 05:38 AM
I think this pushes the discussion back to square one. Why assume Earth is the trend when we have only one example of that sort of planet? Why not assume that the universe is dominated by Venus-like runaway greenhouses? Doesn't it occur to you that making life - i.e. stuff like us - commonplace is simply another attempt to put us at the centre of the universe again?

That is where numbers do make a difference. If we thought there was only one exoplanet in the universe with a mass comparable to Earth and Venus, it would make sense to ask whether that planet would be more likely to be Earth-like or Venus-like... However, given what we know about the number of exoplanets, surely there's room for lots of Earth-like ones and lots of Venus-like ones?

Frank Merton
2012-Dec-25, 05:39 AM
I think this pushes the discussion back to square one. Why assume Earth is the trend when we have only one example of that sort of planet? Why not assume that the universe is dominated by Venus-like runaway greenhouses? Doesn't it occur to you that making life - i.e. stuff like us - commonplace is simply another attempt to put us at the centre of the universe again?I think either you misread me or answered someone else while quoting me. My view is that stuff like us, as you call it, is probably so rare we will never encounter it. Does that put us at the center of the universe? Hardly. The universe is, as has been said before, a pretty big place

Selfsim
2012-Dec-25, 07:29 AM
There are no pure logical factors, including: 'the numbers', or 'the maths', which would underwrite either the 'for' or 'against' arguments. There are no arguments for having any opinions at all! (Which is also where the current data leaves us .. or even, arguably, where the current interpretive theoretical bases combined with the current data, leaves us).If we really didn't know anything at all about the possible existence, possible amount and possible complexity of life on other planetary bodies, then I think words like "indifferent" and "random" would be quite appropriate to the comparison between life there and life here.

Take Mercury, for instance. If we knew nothing at all that was relevant to existence or non-existence of life on Mercury, but were curious about the question, then we would need to consider at least three possibilities.

* Mercury has less life than Earth, perhaps none at all.
* Life on Mercury is equally abundant as life on Earth.
* Life on Mercury is more abundant than life on Earth, perhaps much more abundant.

In fact, however, we do know quite a lot about Mercury — enough to make the existence of any sort of life there seem highly implausible...

Or is that only an "opinion"? Is it perhaps the sort of "opinion" you have in mind when you say "There are no arguments for having any opinions at all! " ?My quote above, prior to the sentence in parentheses, is coming from the Copernican/Mediocrity/Indifference Principles. The sentence inside the parentheses however, allowed for argumentation on a different basis (which is fundamentally not indifferent), and I recognise that this appears to be your particular 'interest zone'.

I think there's some important aspects to consider when coming from the more selective principles encompassed by the Drake Equation, which also closely parallels the principles from which your argument is based. I'll have a think and get back, when I get the time.

In the meantime, have a Merry Christmas!
:)
Cheers


Not sure what you mean by "pummeled"? Does emphatic disagreement constitute "pummeling"? Do you see your own comments — in this thread and others — as a retaliatory "pummel"?Don't worry 'bout it Colin, it was 'figurative' speech ... there's more important points to be made than anything coming from this tack .... :)

Colin Robinson
2012-Dec-25, 07:59 AM
My quote above, prior to the sentence in parentheses, is coming from the Copernican/Mediocrity/Indifference Principles. The sentence inside the parentheses however, allowed for argumentation on a different basis (which is fundamentally not indifferent), and I recognise that this appears to be your particular 'interest zone'.

I think there's some important aspects to consider when coming from the more selective principles encompassed by the Drake Equation, which also closely parallels the principles from which your argument is based. I'll have a think and get back, when I get the time.

In the meantime, have a Merry Christmas!
:)

Merry Christmas Selfsim!

I look forward to reading your further thoughts when you get the time to get back...

Paul Wally
2012-Dec-26, 12:11 PM
Take Mercury, for instance. If we knew nothing at all that was relevant to existence or non-existence of life on Mercury, but were curious about the question, then we would need to consider at least three possibilities.

* Mercury has less life than Earth, perhaps none at all.
* Life on Mercury is equally abundant as life on Earth.
* Life on Mercury is more abundant than life on Earth, perhaps much more abundant.

In fact, however, we do know quite a lot about Mercury — enough to make the existence of any sort of life there seem highly implausible...

Or is that only an "opinion"? Is it perhaps the sort of "opinion" you have in mind when you say "There are no arguments for having any opinions at all! " ?


I see no reason why we have to resort to such truisms.

We know that Mercury is a solid state planet with no liquid solvent, and it as been in that state for a very long time as is evident from the large number of craters on its surface. So how would life evolve on a planet without liquid solvent? Perhaps there exist spaceborne lifeforms (Mercurian dust mites) that could have been carried there through panspermia where they feed on the rock minerals and sunlight, but then why haven't we found any such lifeforms in the lunar rocks brought back by Apollo. What about other such solid state bodies like asteroids and icy moons? If there's spaceborne life on Mercury then why wouldn't there be life on these other bodies?

Another idea to consider is that, just maybe, life can evolve in solid state matter. Sure, we don't know, but it leads to interesting new research questions. For example can life evolve from self-organization of quasi-matter within a large crystal lattice? This is also part of the larger question of condensed matter states where there are also these quasi-material self-organization. These don't rule out the gas giants as possible abodes of quasi-material lifeforms. A very interesting planet in this regard is Neptune, where it is hypothesised that there exists superionic water (http://www.newscientist.com/article/mg20727764.500-weird-water-lurking-inside-giant-planets.html) with hydrogen ions flowing through an oxygen crystal lattice.

Does it mean that I believe or assume any of the above ideas? Certainly not, but it is of great use to consider these ideas and expand our minds in this way. It leads to interesting questions and new avenues of research, theoretical, experimental and exploratory. Does it mean that I assume the so called Copernican principle by considering these ideas. I'm not assuming them to be true so why would I assume the Copernican principle to be true. I'm not even sure whether the Copernican principle has any relevance to such questions. And looking for such life is definitely not the same as looking for Earth-life or Earth-whatever, the terms "Earth-like" and "Exo-life" and "sample of one" being just mental straight-jackets of which the only function is to limit our thinking. The fact remains, we can look for whatever we can think of, and direct our search accordingly.

IsaacKuo
2012-Dec-26, 05:20 PM
Are we certain that Mercury has no liquid solvent? We have detected a lot more water ice in Mercury's polar craters than the Moon's polar craters. Mercury has a lot more gravity than the Moon, so the pressure required for liquid water conditions wouldn't require as much depth. A depth of only 9m would be equivalent pressure to the top of Mt. Everest.

Could Mercury have subsurface lakes of liquid water?

IsaacKuo
2012-Dec-26, 05:43 PM
See, the problem is that the search for ET, in scientific terms, is a test for our present model of universal life.

The idea that the search is about looking specifically for an exact replica of Earth-like life, stands a chance of failing by; (i) not detecting a different type of exo-life, or; (ii) concluding that exo-environmental conditions result in Earth-like life, before we know that, and then excluding non-Earth-like planets.
Actually, scientists do not assume that Earth-like planets are required. As I've already noted, you're just setting up a straw man.

In fact, there is a great deal of interest in searching for life on Mars and Europa, and other planetary bodies which are not Earth-like.

This is obviously not based on the Copernican principle alone, as you set up with your straw man. Rather, it is based on principles of chemistry and biology and physics. There are a lot of properties of liquid water which make it plausibly necessary for naturally evolved life forms. And there are theories about how life evolved which do not require Earth-like photosynthesis. These guide scientific speculation into the possibilities of life on worlds which are not Earth-like.

Our knowledge is constantly growing and changing. My own perspective on the possibilities has been altered by a couple interesting recent discoveries--the confirmation of large amounts of water ice on Mercury, and studies noting the high frequency of planets much closer to the host star than Mercury is to the Sun.

Taking the two together, I find it plausible that there are many solar systems with 1:1 tide locked "hot mercuries" where the dark hemisphere is covered in thick ice. These worlds may be sort of like Europa on the dark side. I find this possibility interesting because previous papers showed how tidal heating of a planet could provide steady geological power for billions of years. But this seemed to only be useful for planets around sufficiently dim hosts, since a bright star would surely deplete the planetary body of volatiles.

These discoveries point to a new (to me) class of potential ET host worlds. Hot mercuries could also be very interesting starting points for spacefaring aliens. Unlike cold Europa-like worlds, these would enjoy extremely plentiful solar power for light-side probes and satellites to exploit. These hypothetical aliens would have much lower escape velocities to deal with, and the lack of an atmosphere allows for cheap "gun" type launchers (such as EM mass drivers).

See, the truth is that scientific speculation on alien life is not limited to Earth-like planets with Earth-like life. Your accusations fall flat, because they just aren't true.

Ie it makes the error of presuming in advance, an unstated assumption about unsupportable frequencies of occurrence, and types of life, and then it gets even worse, by specifically selecting a preferred sample of: 'Earth-like' planets. It also makes the assumption that Earth-like planets cause Earth-like life. (Which is entirely opinion dependent, subject to various wobbly hypotheses, and has zero supporting data).
No, it does not. You're falsely accusing scientists of your own straw man.

Colin Robinson
2012-Dec-26, 09:47 PM
Are we certain that Mercury has no liquid solvent? We have detected a lot more water ice in Mercury's polar craters than the Moon's polar craters. Mercury has a lot more gravity than the Moon, so the pressure required for liquid water conditions wouldn't require as much depth. A depth of only 9m would be equivalent pressure to the top of Mt. Everest.

Could Mercury have subsurface lakes of liquid water?

I'm not sure... You'd need to consider not only pressure, but also temperature. How a specific region can gain heat (e.g. through conduction), and how it can lose heat (e.g. thru radiation into dark sky). A permanently shaded polar region on the surface could lose heat through direct radiation into space, but an underground region wouldn't, though it could lose heat by conduction to a relatively cool surface region.

Maybe we should start a new thread about habitability of Mercury.

Colin Robinson
2012-Dec-27, 12:04 AM
We know that Mercury is a solid state planet with no liquid solvent, and it as been in that state for a very long time as is evident from the large number of craters on its surface. So how would life evolve on a planet without liquid solvent? Perhaps there exist spaceborne lifeforms (Mercurian dust mites) that could have been carried there through panspermia where they feed on the rock minerals and sunlight, but then why haven't we found any such lifeforms in the lunar rocks brought back by Apollo. What about other such solid state bodies like asteroids and icy moons? If there's spaceborne life on Mercury then why wouldn't there be life on these other bodies?

If a Mercurian dust mite fed on minerals, how would it digest them?

Stomach fluids are an example of how life uses a liquid solvent. Of course we know a lot of organisms don't have stomachs as such, but they still use liquid to do chemistry with nutrients, e.g. in their cytoplasm.

I find it easy to imagine an organism using a fluid other than water as its solvent, but not so easy to image one with no fluid solvent at all.

That's why, when I hear that water ice has been detected somewhere, I don't see that as especially relevant to life. More relevant are fluids other than water which could conceivably serve as solvents for a complex chemistry. E.g ammonia, methane, sulfuric acid.

What has this got to do with the mediocrity principle?

Well, mediocrity does not necessarily mean sameness. It means being somewhere in the middle of a range, rather than right at the far end of a range.

When it comes to presence and character of fluids, Earth would seem to be mediocre in several respects.

E.g. If we look at what proportion of a world consists of a liquid that could be potentially be used as a biosolvent... We've know for a long time that various worlds (such as Earth's Moon) consist of rock, rock and rock... But recent findings from Europa and Enceladus suggest that those worlds not only have liquid water, the water is actually a substantial proportion of their bulk mass, whereas Earth's bulk mass (despite its surface oceans) is mainly rock.

Another issue arguably relevant to biochemistry is how much polarity a fluid has. In this respect too, Earth with its liquid water (a polar molecule) is somewhere in the middle of the range, since liquid methane (found on Titan) has zero polarity, whereas liquid sulfuric acid (found in the clouds of Venus) has more polarity than water.

Githyanki
2012-Dec-27, 04:25 AM
It's true; thinking that just because we have one example of life in the known universe and such that, the universe is so large that therefore there must be other forms of life, is fallacious. But really, what harm will come in believing in such? A little less production at work because we're day-dreaming about ETs that may or may not exist?

Paul Beardsley
2012-Dec-27, 04:42 AM
And looking for such life is definitely not the same as looking for Earth-life or Earth-whatever, the terms "Earth-like" and "Exo-life" and "sample of one" being just mental straight-jackets of which the only function is to limit our thinking. The fact remains, we can look for whatever we can think of, and direct our search accordingly.

If you think the use of clear labels and accurate descriptions of how things are is a mental straitjacket, you are rejecting science.

You might not like the fact that we have a sample of one, but until we find a second, independent example of life, that's how it is.

Paul Beardsley
2012-Dec-27, 04:54 AM
It's true; thinking that just because we have one example of life in the known universe and such that, the universe is so large that therefore there must be other forms of life, is fallacious. But really, what harm will come in believing in such? A little less production at work because we're day-dreaming about ETs that may or may not exist?

What is the harm in believing something that is not supported by evidence? Ask a jury that next time you're on trial!

Again, I have absolutely no problem with speculation that is clearly labelled as speculation. Ideas about alien life forms can be fascinating, fun, and possibly even useful.

The problem arises when people stop saying, "I think it could exist," and start saying, "I believe it does exist," and then start mischaracterising cautious people as saying, "I believe it doesn't exist."

Colin Robinson
2012-Dec-27, 05:57 AM
What is the harm in believing something that is not supported by evidence? Ask a jury that next time you're on trial!

In a jury trial, the practical issue, the bottom line, is whether the accused will be set free, or whether the judge will be asked to pass sentence.

In discussion about life beyond Earth, the practical issue is what sort of research programs, if any, will be carried out to test for it.

Back in the sixties, G.Gaylord Simpson wrote a paper call "The Non-prevalence of humanoids". He described search for life beyond Earth as a gamble with the worst odds in history, and he said that exobiology was a science that had not yet proved that its subject matter existed. His bottom line was that looking for life beyond Earth would not be an appropriate use of scientific resources.

Paul, you mentioned earlier in this thread that you will not be surprised if life is found on another planetary body; although you will be irritated when people start saying they knew it all along.

I think I will be more surprised, actually. The surprise for me will not so much be that life is there, but that we terrestrials will finally have made a serious attempt to look for it.


Again, I have absolutely no problem with speculation that is clearly labelled as speculation. Ideas about alien life forms can be fascinating, fun, and possibly even useful.

I agree it may be useful...


The problem arises when people stop saying, "I think it could exist," and start saying, "I believe it does exist," and then start mischaracterising cautious people as saying, "I believe it doesn't exist."

The problem arises when people refuse to take the possibilities seriously. For instance, when a politician refers to radio SETI as a "great Martian hunt", that has "failed to bag a single little green fellow".

I don't find that sort of thing irritating. But I do find it sad.

Paul Beardsley
2012-Dec-27, 06:36 AM
In a jury trial, the practical issue, the bottom line, is whether the accused will be set free, or whether the judge will be asked to pass sentence.

In discussion about life beyond Earth, the practical issue is what sort of research programs, if any, will be carried out to test for it.

My point is, if you think it's OK to believe something that is not evidence-based in one area, there is a danger of doing the same thing in another.


Back in the sixties, G.Gaylord Simpson wrote a paper call "The Non-prevalence of humanoids". He described search for life beyond Earth as a gamble with the worst odds in history, and he said that exobiology was a science that had not yet proved that its subject matter existed. His bottom line was that looking for life beyond Earth would not be an appropriate use of scientific resources.

So he was very pessimistic. Fair enough - others are very optimistic. One may speculate how his opinions would have changed (or not) if he'd learned about the prev


Paul, you mentioned earlier in this thread that you will not be surprised if life is found on another planetary body; although you will be irritated when people start saying they knew it all along.

I think I will be more surprised, actually. The surprise for me will not so much be that life is there, but that we terrestrials will finally have made a serious attempt to look for it.

My emphasis was on life existing rather than the search. But what do you expect? Billions spent on a probe that drills through the Europan ice and delivers a submarine to the ocean beneath?

Or maybe launch a space probe with the specific purpose of looking for Earth-like exoplanets in the habitable zone? Kepler is unlikely to tell us conclusively that life exists on any of the planets it has found, but it's hardly a dismissive attitude towards the idea of searching for life.


The problem arises when people refuse to take the possibilities seriously. For instance, when a politician refers to radio SETI as a "great Martian hunt", that has "failed to bag a single little green fellow".

I don't find that sort of thing irritating. But I do find it sad.

Hmm. An example of how something can be factually accurate (allowing for metaphor) but unhelpful. Personally I think criticising radio SETI is like criticising a blind person for using a cane or a guide dog*.

*Seeing-eye dog in the US.

Selfsim
2012-Dec-27, 08:57 AM
Actually, scientists do not assume that Earth-like planets are required. As I've already noted, you're just setting up a straw man.

In fact, there is a great deal of interest in searching for life on Mars and Europa, and other planetary bodies which are not Earth-like.

This is obviously not based on the Copernican principle alone, as you set up with your straw man.

See, the truth is that scientific speculation on alien life is not limited to Earth-like planets with Earth-like life. Your accusations fall flat, because they just aren't true.

No, it does not. You're falsely accusing scientists of your own straw man.I wish you'd 'get with it', Isaac.

Its not my strawman! Others in this forum, have argued from this perspective … I'll say it a third time .. this thread was intended as my response to that argument … its a fallacious argument, for the reasons outlined in my numerous posts here, Ok?


Rather, it is based on principles of chemistry and biology and physics. There are a lot of properties of liquid water which make it plausibly necessary for naturally evolved life forms. And there are theories about how life evolved which do not require Earth-like photosynthesis. These guide scientific speculation into the possibilities of life on worlds which are not Earth-like.

Our knowledge is constantly growing and changing. My own perspective on the possibilities has been altered by a couple interesting recent discoveries--the confirmation of large amounts of water ice on Mercury, and studies noting the high frequency of planets much closer to the host star than Mercury is to the Sun.

Taking the two together, I find it plausible that there are many solar systems with 1:1 tide locked "hot mercuries" where the dark hemisphere is covered in thick ice. These worlds may be sort of like Europa on the dark side. I find this possibility interesting because previous papers showed how tidal heating of a planet could provide steady geological power for billions of years. But this seemed to only be useful for planets around sufficiently dim hosts, since a bright star would surely deplete the planetary body of volatiles.

These discoveries point to a new (to me) class of potential ET host worlds. Hot mercuries could also be very interesting starting points for spacefaring aliens. Unlike cold Europa-like worlds, these would enjoy extremely plentiful solar power for light-side probes and satellites to exploit. These hypothetical aliens would have much lower escape velocities to deal with, and the lack of an atmosphere allows for cheap "gun" type launchers (such as EM mass drivers).

See, the truth is that scientific speculation on alien life is not limited to Earth-like planets with Earth-like life. Ok .. so lets look at this from the perspective of the Drake Equation (DE), to see where this is heading, eh?

What you (and Colin) are effectively doing here, is either; (i) arguing for more terms to be added to a Drake-like equation which addresses 'potential ET host worlds' or; (ii) arguing reasons leading to assigning some particular value to an existing term of the classical DE, in the light of new found knowledge.

In the case of either (i) or (ii) above, those terms may end up providing improved accuracy in finding specifically, water based lifeforms, by indicating where to look for them, (eg asteroids, moons, Mercuries, etc). They might also increase the numbers of objects under consideration (eg Mercury-like inner planets). Either way, they broaden the focus of the DE away from its original SETI/CETI scope, and lead back towards the even broader focus of the Copernican Principle. Once again, the risk becomes thinking that our newly found knowledge, is actually indicative of some larger set of potential life-bearing classes of 'objects' in the universe. This view is still fallaciously founded because our new found knowledge is not a random selection from the parent population set, (which is covered by ubiquitous Physical and Chemical Laws), because it can only be shown to be correlated with ubiquitous Physical and Chemical Laws in Earth's case.

Earth is not a random sample, and the permutation space in the parent population, is unknown. It cannot thus be said to be indicative of anything in the broader set of the obs universe.

Colin Robinson
2012-Dec-27, 09:21 AM
My point is, if you think it's OK to believe something that is not evidence-based in one area, there is a danger of doing the same thing in another.

Would you be happier if people used the word "suspect" rather than "believe"? This relates to your metaphor of the jury trial. Before a case ever gets to the jury stage, suspects have be identified and investigated...


My emphasis was on life existing rather than the search. But what do you expect? Billions spent on a probe that drills through the Europan ice and delivers a submarine to the ocean beneath?

Well, Europa is certainly an interesting place. Even if we can't get drill thru the ice just yet, it would be nice to have a closer look with a Cassini-style orbiter... I just hope that ESA can do this without NASA's help, because NASA seems to have lost interest in the joint mission they were discussing.

I'd like to see a robot mission to the lakes of Titan, with a mass spectrometer and a microscope. A mission to take a sample of the water gushing out of Enceladus would not be a bad idea. And possibly something to the clouds of Venus also...


Or maybe launch a space probe with the specific purpose of looking for Earth-like exoplanets in the habitable zone? Kepler is unlikely to tell us conclusively that life exists on any of the planets it has found, but it's hardly a dismissive attitude towards the idea of searching for life.

I don't say that a dismissive attitude is taken by all scientists, or by all politicians, or by all sections of the general public... There are all sorts of attitudes and positions... And some important research is certainly being done, including by the Kepler mission.

My point I was making, though, is that there has indeed been a dismissive attitude to astrobiological research among some scientists, and some politicians, as well as by some contributors to this forum.

For instance, there are people who find it questionable that NASA currently funds astrobiologists... There are people who argue that biology depends on specimens, and therefore that the time for astrobiology will be after specimens of alien biota have been found.

I can see the argument, but I have to disagree with it... Because I doubt we'll ever find those specimens without first having specialists in astronomy and biology to plan the search.


Hmm. An example of how something can be factually accurate (allowing for metaphor) but unhelpful. Personally I think criticising radio SETI is like criticising a blind person for using a cane or a guide dog*.*Seeing-eye dog in the US.

The comment I quoted was specifically about a NASA funded radio SETI program, which never got past the planning stage. The comment was certainly unhelpful in the sense that it was part of a successful campaign to kill the NASA program. (Current radio SETI is independent from NASA.)

Whether radio SETI is the best strategy or not, at least the SETI Institute is making a positive effort. As we say in Australia, they are having a go.

IsaacKuo
2012-Dec-27, 10:11 AM
I wish you'd 'get with it', Isaac.

Its not my strawman! Others in this forum, have argued from this perspective … I'll say it a third time .. this thread was intended as my response to that argument … its a fallacious argument, for the reasons outlined in my numerous posts here, Ok?
No matter how many times you repeat your claim that others in this forum argue your straw man, it doesn't make it true.

Your accusation would only be true if those others actually made their argument based on the straw man you claim--in other words, it would only be true if they are arguing based on the Copernican principle alone. But, in fact, they don't. They argue based on ideas about what pressure/temperature/etc environmental conditions are required for chemical properties are required for simple life, complex life, development of technology, etc. If they were arguing based on the Copernican principle, they wouldn't bother with any of those factors.

You wish I would "get with it", and agree with a falsehood you insist upon merely with insistent repetition. Sorry, but I'm not going to "get with it".

Ok .. so lets look at this from the perspective of the Drake Equation (DE), to see where this is heading, eh?

What you (and Colin) are effectively doing here, is either; (i) arguing for more terms to be added to a Drake-like equation which addresses 'potential ET host worlds' or; (ii) arguing reasons leading to assigning some particular value to an existing term of the classical DE, in the light of new found knowledge.
No, what I am looking at really has little to do with the Drake Equation. The Drake Equation is a tool which makes various assumptions which is fine for what it is looking to do. But it's not an appropriate tool for doing things it is not looking to do. It simply isn't set up for considering the possibilities of life on non-Earthlike worlds, or for considering the possibilities of space travel, or self replicating probes, or any number of other things it was simply never meant to consider.

The Drake Equation is a tool for estimating the number of Earth-like worlds with alien civilizations in the galaxy which may be sending radio transmissions to us, assuming no space travel, no space probes, no other complicating factors. It's not a universal tool for investigating alien life. It simply isn't equipped to deal with things outside the scope of its assumptions.

Earth is not a random sample, and the permutation space in the parent population, is unknown. It cannot thus be said to be indicative of anything in the broader set of the obs universe.
Actually, we know a lot about how typical or atypical Earth is, in various aspects, due to actual observations of other planetary bodies. We know a lot about how chemistry and physics work the same on Earth as elsewhere in the universe based on observations on Earth and on the rest of the universe. All of these observations indicate that indeed, the rules of the universe work the same on Earth as they do everywhere else. This has nothing to do with whether or not Earth is a "random sample". They have to do with scientific observations confirming myriad various hypotheses conforming to the principle of mediocrity.

Paul Wally
2012-Dec-28, 01:01 PM
If a Mercurian dust mite fed on minerals, how would it digest them?

Mmm ... the idea is that if there are no fluids (liquid, gas, plasma, other ) on Mercury then, what I propose, is that the organism must have originally emerged some place else where fluidity does exist, and was then carried to Mercury through panspermia, where it exists as a spaceborne extremophile. This hypothetical organism uses sunlight as a source of energy and uses rock minerals as building blocks, to replicate itself. I don't know whether a liquid solvent is absolutely necessary for the functioning of such an organism. There are other physical mechanisms I can think of like mechanical friction for creating finer material, ionization and perhaps electrical and magnetic fields to control the flow of particles through the organism.

Paul Wally
2012-Dec-28, 01:09 PM
Are we certain that Mercury has no liquid solvent? We have detected a lot more water ice in Mercury's polar craters than the Moon's polar craters. Mercury has a lot more gravity than the Moon, so the pressure required for liquid water conditions wouldn't require as much depth. A depth of only 9m would be equivalent pressure to the top of Mt. Everest.

Could Mercury have subsurface lakes of liquid water?

Maybe. Now I'm not so certain anymore about there being no liquid solvent on Mercury.

Paul Wally
2012-Dec-28, 01:25 PM
If you think the use of clear labels and accurate descriptions of how things are is a mental straitjacket, you are rejecting science.

You might not like the fact that we have a sample of one, but until we find a second, independent example of life, that's how it is.

I have no problem with the labels as such, I just don't think they mean much. The fact that we have a sample of one, is reiterated so many times as if its suppose to tell us something important. Well it doesn't. It would be much more meaningful if after we have surveyed a thousand solar systems in detail, and out of the thousand we only found one sample with life.

IsaacKuo
2012-Dec-28, 03:51 PM
I have no problem with the labels as such, I just don't think they mean much. The fact that we have a sample of one, is reiterated so many times as if its suppose to tell us something important. Well it doesn't. It would be much more meaningful if after we have surveyed a thousand solar systems in detail, and out of the thousand we only found one sample with life.
I'm annoyed by those who say we have a sample size of zero, meaning that we have zero examples of alien life. To me, that's worse than noting that we have a sample size of one, which is an important piece of evidence in favor of the possibility of alien life. In fact, the theory that alien life is possible is not on an equal scientific footing as the theory that alien life is impossible.

Our sample size is important, but the things it tells us are actually in favor of the possiblity of alien life, rather than against. See, our sample size is one, and the result is positive! The number of liquid water environments which we have observed and ruled out life in is zero...so far.

But actually, we have some interesting current developments on that front. We have several ongoing investigations of isolated subsurface lakes and mud layers here on Earth. These are not a perfect analog for alien environments, for many reasons, but they are still useful data points. Of these investigations, most have revealed the existence of life--including a the surprising discovery of complex anaerobic life (which was previously considered implausible). So far, no big deal...Earth is teeming with life, so it's not surprising for some of it to cling on in these isolated environments.

But the first samples from Lake Vostok seem devoid of life (fewer than 10 microbes per millileter, consistent with a hypothesis of contamination from the drilling). If, in fact, continued investigation confirms that Lake Vostok is devoid of native life, then this is really a big deal. It would be an honest to goodness example of a significantly sized lifeless environment with long term liquid water conditions and the basic requirements for life as we know it.

Equally significant, in the other direction, would be if we investigate a subsurface lake on an ET planetary body and find life. Such subsurface lakes/oceans exist within our own solar system, but we have not yet sampled any of them. We haven't sampled anywhere outside of Earth with liquid water conditions yet. It's technically challenging to do so, but plainly not impossible to do so given sufficient funding.

Until then, it's severely premature to consider even our own solar system as being surveyed in detail. We actually have significant parts of Earth left to survey. Not only is investigation of Earth's own subsurface lakes directly important, scientifically, it's also important practice for designing missions to investigate ET subsurface lakes.

Paul Beardsley
2012-Dec-28, 04:33 PM
The fact that we have a sample of one, is reiterated so many times as if its suppose to tell us something important. Well it doesn't.

Yes it does. It tells us we can't say whether Earth is the norm or the exception.

I will stop reiterating the fact that we have a sample of one when people stop drawing baseless conclusions.

ASTRO BOY
2012-Dec-28, 08:20 PM
Yes it does. It tells us we can't say whether Earth is the norm or the exception.

I will stop reiterating the fact that we have a sample of one when people stop drawing baseless conclusions.




You have a habit of glossing over the fact that the near infinite extent of the Universe and the huge numbers involved, coupled with the stuff of life being everywhere we look, has most cosmologists believing ET life both primitive and Intelligent, should exist elsewhere.
Even without observational evidence.
Scientists are human and its pretty hard to stop humans from having an educated [or otherwise] opinion on the existence of ET.

Selfsim
2012-Dec-29, 01:36 AM
You have a habit of glossing over the fact that the near infinite extent of the Universe and the huge numbers involved, coupled with the stuff of life being everywhere we look, has most cosmologists believing ET life both primitive and Intelligent, should exist elsewhere.
Even without observational evidence.
Scientists are human and its pretty hard to stop humans from having an educated [or otherwise] opinion on the existence of ET.Scientists can have whatever opinions they like .. (same as anyone else).

Scientists are not the 'holy priests' of science. Science is for everyone, and if someone cannot support their opinions about science topics, using scientific arguments, rationale and empirical evidence, then I don't care what they do for a living … their opinions are simply not part of science. Most scientists studying this topic formally state "we don't know", upfront anyway … So, I'd like to request that you also begin citing this part of what they do say, (alongside of what you say, they say).

Paul Beardsley
2012-Dec-29, 06:02 AM
You have a habit of glossing over the fact that the near infinite extent of the Universe and the huge numbers involved, coupled with the stuff of life being everywhere we look,

I've addressed this over and over and over again. It doesn't matter if the number of opportunities for life to arise is near infinite if the odds against it actually happening are even higher.

And just in case I didn't make myself clear the last thirty times I made this point, I am not saying that the odds against life arising are near infinite. I am saying that as long as we don't know the odds, it's possible that they are such long odds that life only arose once in the entire universe.


has most cosmologists believing ET life both primitive and Intelligent, should exist elsewhere.
Even without observational evidence.
Scientists are human and its pretty hard to stop humans from having an educated [or otherwise] opinion on the existence of ET.

Basically, what Selfsim said. The scientists may be good at their jobs, they may even be wearing lab coats, but the moment they say "I believe..." and make a statement about something that isn't supported by observational evidence, they are not being scientists.

I really wish you'd realise that I am not impressed by your repeated appeals to authority. The one thing that would impress me right now is a sound theory of abiogenesis that gives some indication of the odds of it happening. Without that, there can be no sensible discussion on this subject, as has been demonstrated by at least three lengthy recent threads.

ASTRO BOY
2012-Dec-30, 07:58 PM
Basically, what Selfsim said. The scientists may be good at their jobs, they may even be wearing lab coats, but the moment they say "I believe..." and make a statement about something that isn't supported by observational evidence, they are not being scientists.



And it's not really scientific to pick and chose and rubbish "real" scientists who spend their time at the cutting edge of their disciplines.
Their opinions are based on their knowledge and as I have said many times, there is enough circumstantial evidence out there for the existence of ET life, for cosmolgists to be able to form an opinion....





I really wish you'd realise that I am not impressed by your repeated appeals to authority. The one thing that would impress me right now is a sound theory of abiogenesis that gives some indication of the odds of it happening. Without that, there can be no sensible discussion on this subject, as has been demonstrated by at least three lengthy recent threads.


My appeals to authority and expert opinion has nothing to do with impressing you. They are made to support the "common sense" approach and logical assumptions made in light of present knowledge and observations.
Science is, has and always will be full of logical assumptions based on circumstantial evidence and observations.

Noclevername
2012-Dec-30, 09:07 PM
I feel like I'm watching Congress, here. Everyone's repeating the same arguments in pretty much the same words, and no one's actually being convinced to change any part of their ideas in any way.

Colin Robinson
2012-Dec-30, 09:31 PM
And it's not really scientific to pick and chose and rubbish "real" scientists who spend their time at the cutting edge of their disciplines.
Their opinions are based on their knowledge and as I have said many times, there is enough circumstantial evidence out there for the existence of ET life, for cosmolgists to be able to form an opinion....

I agree with you, Astro Boy.

While the distinction between opinion and knowledge is important, it doesn't really make sense to say that science is only about knowledge, and opinions have nothing to do with it.

Paul Beardsley, you made a comparison earlier between science and a jury trial.

A jury trial happens because a cop forms a suspicion, and follows a line of investigation.

A scientific experiment happens because a scientist, or a group of scientists, form the opinion that the experiment has a chance of finding something of interest. Which is not the same as knowing in advance what the result will be.

In the case of "big science" (like high-energy colliders, or probes sent to other planets) opinions of politicians and the public also make a difference to what experiments are carried out...

Selfsim
2012-Dec-30, 09:41 PM
And it's not really scientific to pick and chose and rubbish "real" scientists who spend their time at the cutting edge of their disciplines.
Their opinions are based on their knowledge and as I have said many times, there is enough circumstantial evidence out there for the existence of ET life, for cosmolgists to be able to form an opinion….I think there are a couple of aspects to this. Scientists wishing to further the volume of the special kind of knowledge gathered by science will, occasionally, choose a particular path (hypothesis, theory, etc), which seems to lead towards the more 'interesting' questions (for them). There is a personal choice they make .. ie: the 'human' aspect, which seems to be the point ASTRO BOY is elevating to a level of importance.

My own view is that for every such personal choice made, there is is a vast volume of hack-work and mundane process which has been executed, in order to gain the priviledge of being able to make that choice.

Why aren't we focusing on the mundanely and rigorously produced knowledge, rather than the 'icing on the cake'? Why elevate the icing when there's almost no discussion about the cake?



My appeals to authority and expert opinion has nothing to do with impressing you. They are made to support the "common sense" approach and logical assumptions made in light of present knowledge and observations.
Science is, has and always will be full of logical assumptions based on circumstantial evidence and observations.And logic alone has been shown to lead to either correct or incorrect conclusions .. this is a well acknowledged fact, (ie: not just my opinion).

Mathematical logic however, is a different kettle of fish … and it seems the stronger a speaker's background and understanding of mathematics, the more apparent the weaknesses in pure logic based discussions become. Some 'give' is required when a discussion reaches this point.

Selfsim
2012-Dec-30, 09:56 PM
A scientific experiment happens because a scientist, or a group of scientists, form the opinion that the experiment has a chance of finding something of interest. Which is not the same as knowing in advance what the result will be. .. And yet, so many discussions in this forum, read so much more into the observation that some scientist (or bunch of 'em) must be pursuing the correct option ... therefore I'm right! {Baloney, I say}


In the case of "big science" (like high-energy colliders, or probes sent to other planets) opinions of politicians and the public also make a difference to what experiments are carried out...And I assert that these often misinformed opinions, are exactly what is being confused with the real science in the discussions in both this, and the 'Space Exploration', Forums.

The opportunity to further critical thinking skills, as way of distinguishing the reality perspective that science has been specifically developed to do, is being almost violated, as a result. Highly counterproductive … and, ultimately detrimental to science!

Denial of the Copernican Principle fallacy in the OP, highlights the same philosophically undistinguished issue.

ASTRO BOY
2012-Dec-30, 10:08 PM
.. And yet, so many discussions in this forum, read so much more into the observation that some scientist (or bunch of 'em) must be pursuing the correct option ... therefore I'm right! {Baloney, I say}



No they form an educated opinion most likely based on that observation, and the most likely scenario is we are not alone.




And I assert that these often misinformed opinions, are exactly what is being confused with the real science in the discussions in both this, and the 'Space Exploration', Forums.


You assert incorrectly...Science is Imagination, Innovativeness, observation, experimentation and all to gain knowledge.




The opportunity to further critical thinking skills, as way of distinguishing the reality perspective that science has been specifically developed to do, is being almost violated, as a result. Highly counterproductive … and, ultimately detrimental to science!



Read my previous answer....You greatly under estimate science





Denial of the Copernican Principle fallacy in the OP, highlights the same philosophically undistinguished issue.


That's your take on the situation and I for one strongly disagree....

Paul Wally
2012-Dec-31, 12:15 AM
A scientific experiment happens because a scientist, or a group of scientists, form the opinion that the experiment has a chance of finding something of interest. Which is not the same as knowing in advance what the result will be.



Well said. I wanna add that science is the process that precedes knowledge, and therefore knowledge is only the end product of that process. We cannot therefore expect scientist to speak only knowledge whenever they open their mouths. Research is a continuing process of coming to know. So the nature of the research process is that it's full of intuition, guess work, reasoning etc.


I think there are a couple of aspects to this. Scientists wishing to further the volume of the special kind of knowledge gathered by science will, occasionally, choose a particular path (hypothesis, theory, etc), which seems to lead towards the more 'interesting' questions (for them). There is a personal choice they make .. ie: the 'human' aspect, which seems to be the point ASTRO BOY is elevating to a level of importance.

You seem to completely disregard the role of creativity in science. Hypotheses are not chosen, they are thought.


My own view is that for every such personal choice made, there is is a vast volume of hack-work and mundane process which has been executed, in order to gain the priviledge of being able to make that choice.

It's not a matter of choice. What hack-work are you talking about? An investigation starts with hypothesising, then the hard work starts of putting the idea to the test. It goes back and forth like that. Hypothesising is part of the hard work. I wouldn't call it mundane though. Science is fun. Ask any scientist.



Why aren't we focusing on the mundanely and rigorously produced knowledge, rather than the 'icing on the cake'? Why elevate the icing when there's almost no discussion about the cake?


We are focussing on the scientific process (the cake). It is you who think there is still something else.



And logic alone has been shown to lead to either correct or incorrect conclusions .. this is a well acknowledged fact, (ie: not just my opinion).

Mathematical logic however, is a different kettle of fish … and it seems the stronger a speaker's background and understanding of mathematics, the more apparent the weaknesses in pure logic based discussions become. Some 'give' is required when a discussion reaches this point.

Mathematics and logic are intrinsically part of modern science.


.. And yet, so many discussions in this forum, read so much more into the observation that some scientist (or bunch of 'em) must be pursuing the correct option ... therefore I'm right! {Baloney, I say}

With "option" I take it you mean hypothesis. An hypothesis cannot be known to be correct, otherwise it wouldn't be an hypothesis anymore.


And I assert that these often misinformed opinions, are exactly what is being confused with the real science in the discussions in both this, and the 'Space Exploration', Forums.

Opinions, whether informed or misinformed, are just opinions nonetheless, and both types can turn out to be right or wrong.


The opportunity to further critical thinking skills, as way of distinguishing the reality perspective that science has been specifically developed to do, is being almost violated, as a result. Highly counterproductive … and, ultimately detrimental to science!

What is this "reality perspective" you're referring to? Scientific realism means that there exists a reality independent of us observing of it, i.e. if aliens exist then they exist, whether we have evidence or not. That is scientific realism.

Selfsim
2012-Dec-31, 02:20 AM
Well said. I wanna add that science is the process that precedes knowledge, and therefore knowledge is only the end product of that process. We cannot therefore expect scientist to speak only knowledge whenever they open their mouths. Research is a continuing process of coming to know. So the nature of the research process is that it's full of intuition, guess work, reasoning etc.So you agree that we shouldn't hold up scientists' opinions necessarily as science then?
(Contrary to ASTRO BOY's thesis on the topic).



I think there are a couple of aspects to this. Scientists wishing to further the volume of the special kind of knowledge gathered by science will, occasionally, choose a particular path (hypothesis, theory, etc), which seems to lead towards the more 'interesting' questions (for them). There is a personal choice they make .. ie: the 'human' aspect, which seems to be the point ASTRO BOY is elevating to a level of importance.You seem to completely disregard the role of creativity in science. Hypotheses are not chosen, they are thought.Choice is an unmotivated thought. There are no reasons behind a choice.



My own view is that for every such personal choice made, there is is a vast volume of hack-work and mundane process which has been executed, in order to gain the priviledge of being able to make that choice.It's not a matter of choice. What hack-work are you talking about? An investigation starts with hypothesising, then the hard work starts of putting the idea to the test. It goes back and forth like that. Hypothesising is part of the hard work. I wouldn't call it mundane though. Science is fun. Ask any scientist.A properly formulated hypothesis requires considerations of past knowledge and experience. No professional scientist is going to publish the first thoughts that pop into mind. There is discipline and rigor involved in order to gain support, which requires many years of formal learning (as an eg).



Why aren't we focusing on the mundanely and rigorously produced knowledge, rather than the 'icing on the cake'? Why elevate the icing when there's almost no discussion about the cake?We are focussing on the scientific process (the cake). It is you who think there is still something else.We are discussing philosophy .. as distinct from science.


Mathematics and logic are intrinsically part of modern science.{Aside: The difference in our 'styles' never ceases to amaze me. Much of what I write here, is to share the distinctions which clarify what I mean by 'reality'. So often you go in the other direction .. ie: to conflate those distinctions. I'm not complaining .. just noting this .. as a contribution towards attaining some kind of mutual understanding}.

I actually agree that science typically draws upon philosophically based logic and mathematical logic, and selects for the optimal value propositions. I don't agree that philosophical logic is an intrinsic part of science. It is an intrinsic part of philosophy, however.

Otherwise, how does one distinguish Metaphysics from science?



.. And yet, so many discussions in this forum, read so much more into the observation that some scientist (or bunch of 'em) must be pursuing the correct option ... therefore I'm right! {Baloney, I say}With "option" I take it you mean hypothesis. An hypothesis cannot be known to be correct, otherwise it wouldn't be an hypothesis anymore.I agree. That is why all hypotheses are options .. take your pick .. (according to personal taste, of course). After all, there can be no reasons for choosing one over the other .. that would be a decision, (which is distinct from being a choice).


Opinions, whether informed or misinformed, are just opinions nonetheless, and both types can turn out to be right or wrong.Agreed .. they're pretty valueless overall, amidst billions of other opinions, too. (Including one's own opinions).

I'll go one step further and say that all opinions originate from past experience (or knowledge). Opinions are thus usually accompanied by reasons, (from past knowledge/experience). If I was to ask a ~3-4 year old child, whether they'd like a strawberry ice-cream or a chocolate one, (and they had never tasted either), then there's a good chance theirs would be a choice, (as distinct from a decision). The test would be to ask them why did they pick what they picked. The verification might be a shrug of the shoulders … ie: (a choice .. for no reasons).



The opportunity to further critical thinking skills, as way of distinguishing the reality perspective that science has been specifically developed to do, is being almost violated, as a result. Highly counterproductive … and, ultimately detrimental to science!What is this "reality perspective" you're referring to? Scientific realism means that there exists a reality independent of us observing of it, i.e. if aliens exist then they exist, whether we have evidence or not. That is scientific realism.Somewhere recently, I have distinguished what I mean by reality (don't know which thread). I know of at least three distinct types:
(i) opinions, beliefs, gut feelings, self-awareness, emotions etc are consistent with the distinction of 'Individual Reality';

(ii) consensus, politics, conspiracy theories, beliefs that science fiction determines the future, etc, 'mainstream' are consistent with the distinction of 'Reality by Consensus' .. it takes agreement y'know! ….

In this conversation, the purpose of distinguishing the above two, is to enable focus on the reality distinguished by science .. ie:

(iii) 'Physical Reality', which is objective, measurable, observable, independently verifiable, and can be shown to be internally self-consistent.

My quote above, was in reference to type (iii) reality.

The Copernican Principle draws on all three types of reality. The interpretation of it, when it comes to 'the numbers' argument however, demonstrates type (i) and type (ii) reality, but fails in qualifying as type (iii).

neilzero
2012-Dec-31, 02:26 AM
Likely the mass center of Mercury is about 1000 c = 1832 f, so 9 kilometers below the poles 500c = 932f may be the temperature. The pressure is high enough for water to be liquid, but that is much too hot for life as we know it. The temperature of Earth 9 kilometers, below the surface is much cooler with rare exceptions and the pressure about 2.8 times higher. Neil

ASTRO BOY
2012-Dec-31, 02:33 AM
So you agree that we shouldn't hold up scientists' opinions necessarily as science then?
(Contrary to ASTRO BOY's thesis on the topic)..


I'm sure Paul can speak for himself but anyhow, why do you insist on misinterpreting all those that hold a different opinion to yourself?
Like me, he probably means that there is more to science then just the end product.....Assumptions, Imagination, Innovation, and even dreaming are just part of the process.


The rest of your post appears to be a rehash of your own unsupported thoughts on the matter and somewhat opinionated.

Selfsim
2012-Dec-31, 06:15 AM
The rest of your post appears to be a rehash of your own unsupported thoughts on the matter and somewhat opinionated.There's a big difference between a 'distinction' and an 'opinion'.

A distinction is a tool for explaining where someone is coming from, in a conversation. They don't have to be right or wrong, or even correct/incorrect, they simply aid in clarifying the principles from which a chosen perspective is being drawn from. It also helps if they're applied consistently.

Its kind of polite behaviour to share one's personal distinctions ... it helps to define the playing field.

Please feel free to share your own ... I'm quite curious as to what they may be.

Paul Beardsley
2012-Dec-31, 06:40 AM
ASTRO BOY, you are continuing to cite "numbers", but whenever you reply to my posts, you choose to ignore my point about unknowns. (Most recently in your reply to my post 97.) This is why, as Noclevername has pointed out, this discussion keeps looping.


And it's not really scientific to pick and chose and rubbish "real" scientists who spend their time at the cutting edge of their disciplines. Their opinions are based on their knowledge and as I have said many times, there is enough circumstantial evidence out there for the existence of ET life, for cosmolgists to be able to form an opinion....

That's not what I am doing at all.

To borrow corporate-speak for a moment, I am saying that scientists are not wearing their scientist hats when they assert conclusions that are not based on data. If you asked them they would almost certainly admit this.


My appeals to authority and expert opinion has nothing to do with impressing you. They are made to support the "common sense" approach and logical assumptions made in light of present knowledge and observations.

It was "common sense" that the Earth is at the centre of the solar system.

It was "common sense" that heavier-than-air flying machines are impossible.

It was "common sense" that God does not play dice.

It was "common sense" that the stars are all shining dots on a sphere, because the alternative is that they are impossibly far away.


Science is, has and always will be full of logical assumptions based on circumstantial evidence and observations.

Circumstantial evidence, hunches, imagination and so on are all fine when it comes to directing the search but not when it comes to asserting conclusions.

Van Rijn
2012-Dec-31, 09:44 AM
Everyone's repeating the same arguments in pretty much the same words, and no one's actually being convinced to change any part of their ideas in any way.

Yes, it's pretty much an infinite loop argument:

A: ET exists.

B: We don't know.

A: ET exists!

B: We don't know!

A: ET really exists!

B: We really don't know!

A: But based on my belief, ET must exist!!!!

B: But I've already pointed out that we don't know!1!!1one!

. . . and so on.

I think it's a lot more interesting discussing how you would search for indications of ET. For instance, SETI searches for interstellar radio transmissions, or indications of Dyson spheres. Or looking for life on Mars, etc.

Paul Beardsley
2012-Dec-31, 11:51 AM
Yes, it's pretty much an infinite loop argument:

I hear ya, but part of the role of CQ is to oppose bad science, which includes statements of certainty where no such certainty exists.

Paul Wally
2012-Dec-31, 12:45 PM
I hear ya, but part of the role of CQ is to oppose bad science, which includes statements of certainty where no such certainty exists.

Astro Boy feels certain that alien life exists elsewhere. You are not providing any good reasons as to why he should change his position. "We don't know" is not a good reason. In fact, it's no reason at all. So yeah, I agree with Van Rijn. This is in infinite loop.

swampyankee
2012-Dec-31, 01:02 PM
Yes, it's pretty much an infinite loop argument:

A: ET exists.

B: We don't know.

A: ET exists!

B: We don't know!

A: ET really exists!

B: We really don't know!

A: But based on my belief, ET must exist!!!!

B: But I've already pointed out that we don't know!1!!1one!

. . . and so on.

I think it's a lot more interesting discussing how you would search for indications of ET. For instance, SETI searches for interstellar radio transmissions, or indications of Dyson spheres. Or looking for life on Mars, etc.

You forgot C: "No it doesn't!"

We have no proof about non-terrestrial life beyond some very specific cases. Heck, it was only a few decades ago that bacteria or archaea were found at depths of one or two km down in the crust and around black and white smokers. A few decades earlier -- before Trieste reached the bottom of Challenger Deep -- the expectation was the deepest parts of the ocean were devoid of life. Unsupported assertations are just that, whether they're negative or positive.

Paul Beardsley
2012-Dec-31, 02:25 PM
Astro Boy feels certain that alien life exists elsewhere. You are not providing any good reasons as to why he should change his position. "We don't know" is not a good reason. In fact, it's no reason at all. So yeah, I agree with Van Rijn. This is in infinite loop.

I don't know if you simply don't get science, or you do but you're choosing to reject it. Anyway, I'm done with this thread.

IsaacKuo
2012-Dec-31, 02:54 PM
Yes, it's pretty much an infinite loop argument:
[...]
I think it's a lot more interesting discussing how you would search for indications of ET. For instance, SETI searches for interstellar radio transmissions, or indications of Dyson spheres. Or looking for life on Mars, etc.
That results in the infinite loop argument dismissing SETI, Dyson spheres, and any other concepts for how to search for evidence of ET as nonsensical gobbledygook speculation.

Solfe
2012-Dec-31, 03:02 PM
I feel like I'm watching Congress, here. Everyone's repeating the same arguments in pretty much the same words, and no one's actually being convinced to change any part of their ideas in any way.

We are standing at the brink of the Alien Cliff. :)

IsaacKuo
2012-Dec-31, 05:05 PM
Likely the mass center of Mercury is about 1000 c = 1832 f, so 9 kilometers below the poles 500c = 932f may be the temperature. The pressure is high enough for water to be liquid, but that is much too hot for life as we know it. The temperature of Earth 9 kilometers, below the surface is much cooler with rare exceptions and the pressure about 2.8 times higher. Neil
The depth I was asking about was 9m, not 9km. 9m below the surface of an ice filled crater would correspend to the pressure at the top of Mt. Everest (which is sufficient pressure for liquid water, and life as we know it).

Van Rijn
2013-Jan-01, 02:49 AM
That results in the infinite loop argument dismissing SETI, Dyson spheres, and any other concepts for how to search for evidence of ET as nonsensical gobbledygook speculation.

Once it's established that someone is making arguments from personal incredulity, and does not have an actual scientific argument, there isn't much else to discuss with them. But, they aren't the only people in such discussions, and it is possible to have useful discussions on SETi, Dyson spheres, etc. with others that aren't putting personal (dis)belief ahead of science.

Van Rijn
2013-Jan-01, 03:04 AM
You forgot C: "No it doesn't!"

We have no proof about non-terrestrial life beyond some very specific cases.


Could you define "non-terrestrial life"? I'm not aware of any established examples of non-terrestrial (non-Earth) life. Or do you just mean life that isn't on land (sea life), in which case there are many examples? But I don't see what that has to do with the thread topic.




Heck, it was only a few decades ago that bacteria or archaea were found at depths of one or two km down in the crust and around black and white smokers. A few decades earlier -- before Trieste reached the bottom of Challenger Deep -- the expectation was the deepest parts of the ocean were devoid of life.


Which is an example of adaptability, but again I'm not seeing the relevance to the thread topic.



Unsupported assertations are just that, whether they're negative or positive.

Well, yes, if someone asserts ET life must exist, or asserts that ET life cannot exist, those would both be unsupported assertions. "We don't know," however, is just a statement of current limits of knowledge.

ASTRO BOY
2013-Jan-01, 09:33 PM
Could you define "non-terrestrial life"?
Which is an example of adaptability, but again I'm not seeing the relevance to the thread topic.




And there's nothing stopping the example of "adaptability" from extending beyond Earth, especially if "Panspermia can be shown to be valid and I believe that is a distinct possibility.







Well, yes, if someone asserts ET life must exist, or asserts that ET life cannot exist, those would both be unsupported assertions. "We don't know," however, is just a statement of current limits of knowledge.


Well if we only had a few hundred stars in the Universe and one galaxy and the "stuff of life" was contained in one small part of the Universe, then the assertion that "we are alone" would be supported somewhat.
But the reality of the situation is of course that we have more stars in the Universe then grains of sands on all the beaches in the world, and the "stuff of life" is everywhere we look, which in my opinion [and it appears to be the opinion of most professional astronomers/cosmologists] makes the assumption of ET life elsewhere a valid assumption.

Once again before people start putting words into my mouth, I do realise that the absolute correct scientific answer to the question of ET is "We do not know for certain".
But science is more then just "absolute correct scientific answers" and if that "absolute correct scientific answer" is we don't know, then it is quite valid and part of human nature for scientists/astronomers/cosmologists to formulate an opinion based on what observational data we do have [size numbers and the stuff of life] to believe that we overwhelmingly are not alone.

And that is all part and parcel of science.

swampyankee
2013-Jan-01, 10:03 PM
Could you define "non-terrestrial life"? I'm not aware of any established examples of non-terrestrial (non-Earth) life. Or do you just mean life that isn't on land (sea life), in which case there are many examples? But I don't see what that has to do with the thread topic.

Life that is not on Earth. We have, I believe, fairly strong evidence that there is no macroscopic, surface dwelling life on the other solid bodies in the Solar System.





Which is an example of adaptability, but again I'm not seeing the relevance to the thread topic.

They are examples of beliefs concerning life in specific habitats that were overturned upon investigation. Life on the abyssal plains was, at one time, considered impossible, as was life in subterranean layers of rocks. So, for that matter, was the very idea of black smokers with ecosystems that seem totally independent of insolation.



Well, yes, if someone asserts ET life must exist, or asserts that ET life cannot exist, those would both be unsupported assertions. "We don't know," however, is just a statement of current limits of knowledge.

Agreed; "We don't know" is the only answer which is currently supported by evidence

ASTRO BOY
2013-Jan-01, 11:51 PM
Life that is not on Earth. We have, I believe, fairly strong evidence that there is no macroscopic, surface dwelling life on the other solid bodies in the Solar System.


I'm pretty sure that is not true...more to the point we probably have no evidence either way, but the hint of the probable presence of evidence could be forthcoming from Enceladus and the interesting icy plumes that have been observed.
In fact I did read somewhere about the possibility to examine this in more detail with a possibility of an Earth return mission with samples.
And of course "absence of evidence is not evidence of absence, and the solar system/galaxy/Universe are all pretty big.









Agreed; "We don't know" is the only answer which is currently supported by evidence

The "we dont know" answer speaks for itself due to the lack of unquestionable evidence either way.
But numbers extent and the homogenious Isotropic nature of the Universe [in itself a logical assumption] leads to strong views by experts in the industry [which leaves me out in the cold] that life elsewhere most likely exists or has existed.

Van Rijn
2013-Jan-02, 08:19 AM
Life that is not on Earth. We have, I believe, fairly strong evidence that there is no macroscopic, surface dwelling life on the other solid bodies in the Solar System.


Okay. Maybe I'm misunderstanding your statement, but my issue was with your statement that "We have no proof about non-terrestrial life beyond some very specific cases." That, to me, sounded like you were claiming there was proof of specific cases of non-terrestrial life.


They are examples of beliefs concerning life in specific habitats that were overturned upon investigation. Life on the abyssal plains was, at one time, considered impossible, as was life in subterranean layers of rocks.


But again, that is about adaptability of already existing life, and we already knew there was life that could be carried there. It is a different issue than the question of life arising or being carried to other worlds.

ASTRO BOY
2013-Jan-02, 08:37 AM
But again, that is about adaptability of already existing life, and we already knew there was life that could be carried there. It is a different issue than the question of life arising or being carried to other worlds.

For that we need to show the validity of "Panspermia" and which I do hold as fairly likely eventually..

Van Rijn
2013-Jan-02, 09:12 AM
And there's nothing stopping the example of "adaptability" from extending beyond Earth


Incorrect: If there is no life, there will be no adaptation. The thread discussion is about the existence of ET life. The evolutionary adaptability of existing Earth life to fit specific Earth environments is not important to that discussion, since we already know there is life here, and it is already established that life can be transported around the planet (unlike panspermia, which is not established).


Once again before people start putting words into my mouth, I do realise that the absolute correct scientific answer to the question of ET is "We do not know for certain".
But science is more then just "absolute correct scientific answers" and if that "absolute correct scientific answer" is we don't know,


But what is useful is what we can test. Discussions how we could test or search for ET life could be scientifically useful, but talking about beliefs doesn't do anything to advance science.

ASTRO BOY
2013-Jan-02, 09:56 AM
Incorrect: If there is no life, there will be no adaptation. The thread discussion is about the existence of ET life. The evolutionary adaptability of existing Earth life to fit specific Earth environments is not important to that discussion, since we already know there is life here, and it is already established that life can be transported around the planet (unlike panspermia, which is not established)..

No, it's not incorrect....
Panspermia is a legitimate scientific hypothesis based on the assumption ET did/does exist somewhere/sometime and some of that is transferred by planetary debris throughout the system.
Science is based on many logical assumptions.




But what is useful is what we can test. Discussions how we could test or search for ET life could be scientifically useful, but talking about beliefs doesn't do anything to advance science.


Wrong again....Science advances and progresses via many different means including beliefs along with Imagination, speculation and logical assumptions based on circumstantial observational data.
Plus of course you have taken what I said out of context....
the full statement was thus.......

">>>Once again before people start putting words into my mouth, I do realise that the absolute correct scientific answer to the question of ET is "We do not know for certain".
But science is more then just "absolute correct scientific answers" and if that "absolute correct scientific answer" is we don't know,
then it is quite valid and part of human nature for scientists/astronomers/cosmologists to formulate an opinion based on what observational data we do have [size numbers and the stuff of life] to believe that we overwhelmingly are not alone.

And that is all part and parcel of science.<<<<"
The above taken from post 120

Selfsim
2013-Jan-02, 10:01 AM
But what is useful is what we can test. Discussions how we could test or search for ET life could be scientifically useful ...The only life we know how to test for, is Earth-life.

Earth-life tests are scientifically useful.

Discussions on how we could test for ET life, can't be 'scientifically useful' .. by definition.

Testing for whether our present model of life might be universal however, is scientifically useful.

IsaacKuo
2013-Jan-02, 02:46 PM
The only life we know how to test for, is Earth-life.
This is untrue. SETI, in particular, does not assume life which is similar to Earth's. Instead, it looks for radio signals which show signs of mathematical and/or scientific knowledge.

Also, Dyson sphere searches look for the spectral signature of a structure which makes sense for an artificial structure but which couldn't be a natural structure.

Earth-life tests are scientifically useful.

Discussions on how we could test for ET life, can't be 'scientifically useful' .. by definition.
Wrong.

Van Rijn
2013-Jan-02, 08:20 PM
No, it's not incorrect....


So are you claiming there will be evolutionary adaptation even if there is no life? What is "not incorrect"?



Panspermia is a legitimate scientific hypothesis based on the assumption ET did/does exist somewhere/sometime and some of that is transferred by planetary debris throughout the system.


. . . or distributed between systems. I'm quite familiar with the hypothesis. It is not established that panspermia occurs. There is no existing evidence supporting the hypothesis.



Wrong again....Science advances and progresses via many different means including beliefs along with Imagination, speculation and logical assumptions based on circumstantial observational data.


Wrong? So you don't think testing is useful?

Speculation is useful as the starting point for developing hypotheses to be tested. It isn't useful if you're just going to insist on beliefs and ignore science.



Plus of course you have taken what I said out of context....


I don't see where the additional text is relevant to my comment, which is why I didn't include it in the first place. I'm not trying to put words in your mouth, and I have no interest in the "I believe"/"We don't know" infinite loop argument. I was just pointing out where you can have scientifically useful discussions, as opposed to constant reiteration of a pointless argument.

ASTRO BOY
2013-Jan-02, 08:41 PM
So are you claiming there will be evolutionary adaptation even if there is no life? What is "not incorrect"?



I withdraw my incorrect remark on your statement...What you said appears correct.
Panspermia though could logically be a legitimate process for transferring life beyond Earth, or from another Astronomical body to Earth.
The debate about ALH 84001 still appears to have its proponents and detractors.




Wrong? So you don't think testing is useful?

Speculation is useful as the starting point for developing hypotheses to be tested. It isn't useful if you're just going to insist on beliefs and ignore science.

No one said testing isn't useful........and I don't Ignore science, but in the event of the "infinite loop" you speak of, where science literally does not know, scientists are allowed to form opinions and beliefs, based on circumstantial evidence.........and despite claims to the contrary, all that is still part and parcel of science.
And of course your statement thus.... "but talking about beliefs doesn't do anything to advance science." is wrong.




I don't see where the additional text is relevant to my comment, which is why I didn't include it in the first place. I'm not trying to put words in your mouth, and I have no interest in the "I believe"/"We don't know" infinite loop argument. I was just pointing out where you can have scientifically useful discussions, as opposed to constant reiteration of a pointless argument.


I dont see it as a pointless argument. I see it as a logical scientific assumption.

Selfsim
2013-Jan-02, 08:53 PM
This is untrue. SETI, in particular, does not assume life which is similar to Earth's. Instead, it looks for radio signals which show signs of mathematical and/or scientific knowledge.… and deliberate RF carrier modulation, with the intent of communicating over distances, is known to be characteristic of .. what type of life?

Please demonstrate 'untrue'. (I'd recommend in a new thread).


The only life we know how to test for, is Earth-life.Also, Dyson sphere searches look for the spectral signature of a structure which makes sense for an artificial structure but which couldn't be a natural structure.Where has the knowledge come from, which allows for eliminating every possibility other than spectral signatures having been produced by 'artificial' means? Ie: what conclusively defines 'artificial'?

Where does 'what makes sense' come from, (as it pertains to life)?



Earth-life tests are scientifically useful.

Discussions on how we could test for ET life, can't be 'scientifically useful' .. by definition.
Wrong.How can discussions about life tests which by definition, are derived from already existing empirically based knowledge of Earth-life, increase scientific knowledge (value), other than by furthering the spread of what is already known about Earth-life?
Particularly so, in the absence of any other known instances of life?

(I'd suggest answering in a new thread).

Van Rijn
2013-Jan-02, 08:56 PM
The only life we know how to test for, is Earth-life.


As IsaacKuo pointed out, this is incorrect.


Discussions on how we could test for ET life, can't be 'scientifically useful' .. by definition.


No, only by your beliefs. It's telling that you have dismissed future exoplanet examinations for life, megastructure searches, even radio SETI searches: Essentially, you seem to be rejecting any methods that could potentially turn "we don't know" into "we do know."

ASTRO BOY
2013-Jan-02, 08:58 PM
. . . or distributed between systems. I'm quite familiar with the hypothesis. It is not established that panspermia occurs. There is no existing evidence supporting the hypothesis.





Just quickly on the hypothesis of Panspermia.....Scientists do appear to be taking it seriously despite lack of direct evidence.
The following article talks on the subject with regards to Super Earths.

">>>>
Super-Earth unlikely able to transfer life to other planets
March 20, 2012 by Brian Peloza

While scientists believe conditions suitable for life might exist on the so-called "super-Earth" in the Gliese 581 system, it's unlikely to be transferred to other planets within that solar system.


"One of the big scientific questions is how did life get started and how did it spread through the universe," said Jay Melosh, distinguished professor of earth and atmospheric sciences. "That question used to be limited to just the Earth, but we now know in our solar system there is a lot of exchange that takes place, and it's quite possible life started on Mars and came to Earth. There's also been a great deal of discussion about the possible spread of life in the universe from star to star."

Moon rocks and Mars meteorites have been found on Earth, which led Melosh to previously suggest living microbes could be exchanged among planets in a similar manner.

more......

http://phys.org/news/2012-03-super-earth-life-planets.html

ASTRO BOY
2013-Jan-02, 09:05 PM
With regards to my previous post and the claim that Super Earths would be unlikely to transfer life to other planets.....But isn't the reverse true?...That is a Super Earth would be far more likely to attract life from another body in the event of a cosmic explosion or collision.

Selfsim
2013-Jan-02, 11:24 PM
The only life we know how to test for, is Earth-life.As IsaacKuo pointed out, this is incorrect.IsaacKuo seems to be unaware that the tests of which he speaks, are derived from knowledge of Earth-life.

What I'd like to know is how you folk seem to have fallen into the belief that terms like 'correct' and 'incorrect', can be legitimately applied to something which is scientifically unknown to exist, and for which there is exactly zero empirical data for? (Let alone that missing data, somehow being morphed into 'evidence' of anything).


No, only by your beliefs. It's telling that you have dismissed future exoplanet examinations for life, megastructure searches, even radio SETI searches: Essentially, you seem to be rejecting any methods that could potentially turn "we don't know" into "we do know."The hypothesis that: 'exo-life might exist', is only scientifically valid because tests exist for carbon-based Earth-life. If these tests cannot be shown to exclude (when implemented over vast distances), other possible natural phenomena capable of emulating Earth-based 'bio-signatures' ... then where is the scientific value of the specific hypothesis, other than by furthering our knowledge of how to test locally for carbon-based life, or perhaps by motivating some improvements upon observation technology precisions, which have other more substantial motivating factors, anyway?

Tests which can be executed remotely, (like SETI RF searches), presume an interpretive model based solely on knowledge of how our version of 'intelligent, communicative' Earth-life, communicates. Such a test can only be shown to be valid in this highly limited case*, and there is no evidence so far for its existence other than from Earth. Using Earth as a statistical sample in this case, fails the pre-requisite test of being demonstrated as being a random sample, in an arbitrarily selected, volume limited, finite parent population of object sets, contained by the observable universe, so even in theory, concluding that Earth is a valid sample for statistical induction, is flawed. The argument is also flawed in philosophical logic, as it relies on a circular premise, (derived from the inappropriate inverse application of typically, scientifically admissable principles).

Invoking the Copernican Principle (CP), carries with it, uncertainties associated with remote measurement (im)precisions, and their applicability at certain scales. (Ie: the very small scales … which turn out to be a known, necessary precision condition, for molecular biology testing). The CP is simply irrelevant to the issue, and yet, it is frequently, inappropriately invoked in such discussions.

None of this has anything to do with 'Selfsim'. The problem is confronting the known facts without conflating them with sci-fi, and a lack of consideration of what Selfsim is merely pointing out.

I have proposed, (multiple times over), that the only resolution to these issues, (known by 'Selfsim'), is local exploration and the execution of known biology tests on samples, gathered from within technologically reachable distances. Any inferences intended from accusations of 'dismissiveness' or 'rejection' of ideas, are falsified by such a proposition. Keep an eye out for others, if and when they occur.
Its 'a work in progress', y'know ...

Footnote:
* Known to be highly limited, based on humans being the only life-form known on Earth, to be capable of communicating over distances, using RF technologies.

Paul Wally
2013-Jan-02, 11:42 PM
… and deliberate RF carrier modulation, with the intent of communicating over distances, is known to be characteristic of .. what type of life?

This has nothing to do with the "type of life" sending the signal. There are mathematical methods for determining the information content and complexity of any signal, and to distinguish it from mere random noise.

Selfsim
2013-Jan-03, 01:08 AM
… and deliberate RF carrier modulation, with the intent of communicating over distances, is known to be characteristic of .. what type of life?This has nothing to do with the "type of life" sending the signal. There are mathematical methods for determining the information content and complexity of any signal, and to distinguish it from mere random noise.Well, Ok … so for this one, I'll go along with ya (temporarily) ...

So, if it has nothing to do with the "type of life sending the signal" ... what value is specifically SETI adding, by looking for such signals? (Ie: we already seem to know what you say … from some other source, which has no dependencies on any particular discoveries from SETI …?...)

caveman1917
2013-Jan-03, 01:29 AM
… and deliberate RF carrier modulation, with the intent of communicating over distances, is known to be characteristic of .. what type of life?

That is fallacious reasoning. That earth-based life produces distinct radio waves that can be detected doesn't mean that detection of those radio waves implies they were created by earth-based life.


Where has the knowledge come from, which allows for eliminating every possibility other than spectral signatures having been produced by 'artificial' means? Ie: what conclusively defines 'artificial'?

It doesn't need a conclusive definition. If we pick up the fibonacci sequence in a radio wave, we can be fairly certain that it was created artificially. Specifically because we can predict what the next number we will receive will be before we receive it. That doesn't completely rule out the possibility that by some freak chance some natural process produced part of the fibonacci sequence encoded in a radio wave just at the time we are receiving it, but it strongly suggests the source isn't natural.

Selfsim
2013-Jan-03, 08:18 AM
That is fallacious reasoning. That earth-based life produces distinct radio waves that can be detected doesn't mean that detection of those radio waves implies they were created by earth-based life.Well hello caveman ... good to see your presence in this forum.

So, my answer is roughly the same as in post #137.


It doesn't need a conclusive definition. If we pick up the fibonacci sequence in a radio wave, we can be fairly certain that it was created artificially. Specifically because we can predict what the next number we will receive will be before we receive it. That doesn't completely rule out the possibility that by some freak chance some natural process produced part of the fibonacci sequence encoded in a radio wave just at the time we are receiving it, but it strongly suggests the source isn't natural.Ok ... say, for example, we had no knowledge whatsoever of the model representing the Fibonacci sequence, and we had no pattern matching capabilities, (ie: remove those parts of the 'human intelligence' factor), could we be 'fairly certain' that such a signal was created by an artificial means, and could we then predict the next number in the sequence? If not, then there's something about 'human intelligence' which must be factored into the expectation of 'fairly certain'.

The point is, that modelled knowledge, is something developed by humans, (using humans' main distinguishing attribute ... ie: 'intelligence'). RF carriers modulated according to the model representing the Fibonnaci sequence, means human intelligence. At the moment, that's all it means. Discussions about it, in an ETI conversation in the present, are still about human intelligence ... because RF carriers modulated according to the model representing the Fibonnaci sequence, from outside of Earth, are unknown.

If, and when, such a sequence is found being radiated from outside of Earth's locale, then I agree we might be talking about 'fairly certain' evidence of ET Intelligence, but until that happens, all its about our own intelligence.

This whole sub-conversation is summarised below. Its at risk of being further taken out of context ... (it has already)... so I'll refresh the exact conversation ...



But what is useful is what we can test. Discussions how we could test or search for ET life could be scientifically useful ...
The only life we know how to test for, is Earth-life.

Earth-life tests are scientifically useful.

Discussions on how we could test for ET life, can't be 'scientifically useful' .. by definition.

Testing for whether our present model of life might be universal however, is scientifically useful.

The only life we know how to test for, is Earth-life.This is untrue. SETI, in particular, does not assume life which is similar to Earth's. Instead, it looks for radio signals which show signs of mathematical and/or scientific knowledge.
… and deliberate RF carrier modulation, with the intent of communicating over distances, is known to be characteristic of .. what type of life?Note the underlined statement .... if we were to detect a signal, which according to our human intelligence derived model of life, implied that that model might be universal, then it would certainly be scientifically useful. Its that human intelligence derived model, coupled with data confirming the signal's source to be extra-terrestrial, (which also allows for ruling out other possibilities), which returns the scientific value .... Not some discussion on how we might test for something which has completely arbitrary, unconstrained and preconceived meaning, such as 'ETI life'.

The signal has to be detected before 'ETI life' can be decoupled from human intelligence, and until that happens, (under this particular scenario), I do not see that discussions of how we might test for 'ETI life', can be of scientific usefulness, (beyond incidental), at all.

caveman1917
2013-Jan-03, 08:55 AM
Ok ... say, for example, we had no knowledge whatsoever of the model representing the Fibonacci sequence, and we had no pattern matching capabilities, (ie: remove those parts of the 'human intelligence' factor), could we be 'fairly certain' that such a signal was created by an artificial means, and could we then predict the next number in the sequence? If not, then there's something about 'human intelligence' which must be factored into the expectation of 'fairly certain'.

The point is, that modelled knowledge, is something developed by humans, (using humans' main distinguishing attribute ... ie: 'intelligence'). RF carriers modulated according to the model representing the Fibonnaci sequence, means human intelligence. At the moment, that's all it means. Discussions about it, in an ETI conversation in the present, are still about human intelligence ... because RF carriers modulated according to the model representing the Fibonnaci sequence, from outside of Earth, are unknown.

If, and when, such a sequence is found being radiated from outside of Earth's locale, then I agree we might be talking about 'fairly certain' evidence of ET Intelligence, but until that happens, all its about our own intelligence.

This whole sub-conversation is summarised below. Its at risk of being further taken out of context ... (it has already)... so I'll refresh the exact conversation ...

Note the underlined statement .... if we were to detect a signal, which according to our human intelligence derived model of life, implied that that model might be universal, then it would certainly be scientifically useful. Its that human intelligence derived model, coupled with data confirming the signal's source to be extra-terrestrial, (which also allows for ruling out other possibilities), which returns the scientific value .... Not some discussion on how we might test for something which has completely arbitrary, unconstrained and preconceived meaning, such as 'ETI life'.

The signal has to be detected before 'ETI life' can be decoupled from human intelligence, and until that happens, (under this particular scenario), I do not see that discussions of how we might test for 'ETI life', can be of scientific usefulness, (beyond incidental), at all.

Certainly with SETI we are looking for intelligence that we can somehow recognize (it would be pretty pointless searching for something that you couldn't even recognize if you found it). So of course we are, in a certain sense, looking for something with some commonalities with ourselves.

I don't really understand your objection. Is it that we should say that we are looking whether an aspect of ourselves, ie human intelligence, exists somewhere else in the universe in some recognizable form? If that is it, then sure, i don't think anybody would disagree. When people say they are looking for extraterrestrial intelligence, they don't mean "an intelligence so removed from our own that we couldn't recognize it", but "an intelligence quite like our own but produced somewhere else in the universe". The "extraterrestrial" modifier on intelligence doesn't mean that it is a completely different form of intelligence (though it wouldn't be exactly the same either of course), it means that the intelligence is from a different source than ourselves.

Selfsim
2013-Jan-03, 10:33 AM
I don't really understand your objection. Is it that we should say that we are looking whether an aspect of ourselves, ie human intelligence, exists somewhere else in the universe in some recognizable form? If that is it, then sure, i don't think anybody would disagree. When people say they are looking for extraterrestrial intelligence, they don't mean "an intelligence so removed from our own that we couldn't recognize it", but "an intelligence quite like our own but produced somewhere else in the universe". The "extraterrestrial" modifier on intelligence doesn't mean that it is a completely different form of intelligence (though it wouldn't be exactly the same either of course), it means that the intelligence is from a different source than ourselves.I'm not objecting to anything, actually. It seems others are objecting to what I stated in my initial reply to Van Rijn, and have accused me of being: 'incorrect', 'fallacious', 'untrue' and deliberately obstructing others from somehow magically turning "what we don't know" into "we do know." '

Until we actually find ETI signals, all we have is a human based intelligence model to interpret any observations through. Same goes for remote detection of non-intelligent 'ET life' except in that case, it is a non-intelligent Earth-life model we have to interpret from. Until some kind of confirmation is made using our already developed biological Earth-life tests and whatever other tests we might develop at the time of discovery, which would be based on the nature of that discovery, I cannot see any means for us to advance in scientific knowledge about 'ET life', beyond where we currently stand, (which is basically where its always stood), other than by local exploration missions armed to the hilt with all our best biological life tests, Earth based lab testing, ET telling us directly about themselves, or some breakthrough in abiogenesis.

I cannot see how discussions about tests based on someone's opinions of what 'ET life' might, or might not be, or be capable of, are of any value to science, whatsoever beyond what we already know Earth-life to be, and what its demonstrated to be capable of. (Which is basically what I said in my response).

The search for 'ET life' is the scientific test for the hypothesis of a universal model of life. That model has only Earth validity until it can be shown to be directly applicable in diagnosing a single instance ET life. Once, (and if), it does that, then science can make statistical statements about distributions, probabilites and lotsa stuff .. but until then, it can't. (Even though many seem to think it can, and they can).

Paul Wally
2013-Jan-03, 11:03 AM
Until we actually find ETI signals, all we have is a human based intelligence model to interpret any observations through.

But for us, all physical phenomena require human intelligence to interpret them. I don't see why you think radio signals are somehow a special case as far as the interpretation of phenomena is concerned.

Van Rijn
2013-Jan-03, 12:37 PM
IsaacKuo seems to be unaware that the tests of which he speaks, are derived from knowledge of Earth-life.


IsaacKuo was referring to tests of technology (SETI radio and megastructure searches), NOT a test of biology.



What I'd like to know is how you folk seem to have fallen into the belief that terms like 'correct' and 'incorrect', can be legitimately applied to something which is scientifically unknown to exist, and for which there is exactly zero empirical data for?


Ask someone who made that argument. I pointed out that your claim that we can only test for Earth life is incorrect. That's like saying we couldn't test for exoplanets before the first discovery, or could only test for exoplanets that were identical to the planets in the solar system.

You are going well beyond the "we don't know" position, and instead claiming unreasonable restrictions on what can be tested.


None of this has anything to do with 'Selfsim'. The problem is confronting the known facts without conflating them with sci-fi, and a lack of consideration of what Selfsim is merely pointing out.


Unfortunately, your arguments often seem to go beyond established facts onto dismissals from personal incredulity. Speaking of which, "sci-fi" is not a useful term in this context. There are many definitions of "sci-fi" and it isn't clear what you mean by the term (except that it generally seems to involve your personal incredulity regardless of physical plausibility). If you want to argue against an idea, show why it won't work by the science. Saying it is "sci-fi" or is "impractical" with no additional context is useless.

Incidentally, most of the science discussion on this board involves stuff that I used to read about in science fiction stories (like exoplanet discoveries, asteroid missions, Mars missions, now with a nuclear powered robot that shoots at rocks with it laser, Saturn missions with close-up views of the rings, and on and on).

This is everyday stuff, but all of it would have been incredible science fiction in my teenage years. So a comment about "sci-fi" (especially when you have provided no definition of what you mean by the term) isn't useful, and generally just looks like another dismissal from personal incredulity.


I have proposed, (multiple times over), that the only resolution to these issues, (known by 'Selfsim'), is local exploration and the execution of known biology tests on samples, gathered from within technologically reachable distances. Any inferences intended from accusations of 'dismissiveness' or 'rejection' of ideas, are falsified by such a proposition.


Except that you have dismissed future atmospheric studies of exoworlds for life studies, but I don't see where you have established why they must be excluded.

ASTRO BOY
2013-Jan-03, 07:56 PM
If the hard nose mainstream straight down the line scientific methodology of one or two in this thread were to actually prevail in the science community in general, I believe we would still be stagnating in the dark ages....Again, at the risk of repeating myself, science is as much Imagination, innovation, assumptions and even dreaming as is knowledge.

Swift
2013-Jan-03, 09:40 PM
Again, at the risk of repeating myself, science is as much Imagination, innovation, assumptions and even dreaming as is knowledge.
As a working scientist for over 30 years (PhD in Chemistry) I have to disagree. Sure, imagination and dreaming is important, but it is not equal to knowledge. Science is fundamentally a data driven endeavor. It doesn't matter what you think if you cannot prove it.

Imagination is the starting point; then the really hard work begins to prove your idea.

ASTRO BOY
2013-Jan-03, 09:51 PM
As a working scientist for over 30 years (PhD in Chemistry) I have to disagree. Sure, imagination and dreaming is important, but it is not equal to knowledge. Science is fundamentally a data driven endeavor. It doesn't matter what you think if you cannot prove it.

Imagination is the starting point; then the really hard work begins to prove your idea.

Everything has a starting point, and yes certainly, then the hard yakka begins.
But that starting point is important.

A great man also once said....
"Imagination is more Important then Knowledge" although I believe he did not mean it as literally as that, he was trying to make an important point.

Van Rijn
2013-Jan-03, 11:41 PM
If the hard nose mainstream straight down the line scientific methodology of one or two in this thread were to actually prevail in the science community in general, I believe we would still be stagnating in the dark ages....


That doesn't make sense to me: "Mainstream scientific methodology" has been vital to making scientific discoveries. There will be no stagnation if scientific methodology prevails. The problem arguments in this thread have been those that put belief (or disbelief) ahead of scientific methodology.

ASTRO BOY
2013-Jan-04, 12:24 AM
That doesn't make sense to me: "Mainstream scientific methodology" has been vital to making scientific discoveries. There will be no stagnation if scientific methodology prevails. The problem arguments in this thread have been those that put belief (or disbelief) ahead of scientific methodology.


The great discoveries and thoughts have been by those that step outside the square so to speak....
Mainstream Science without Imagination and dreams will stagnate....
Imagination and dreams without mainstream knowledge and scientific research will stagnate as well...
They go hand in hand is what I am saying.

Swift
2013-Jan-04, 02:53 AM
Everything has a starting point, and yes certainly, then the hard yakka begins.
But that starting point is important.

A great man also once said....
"Imagination is more Important then Knowledge" although I believe he did not mean it as literally as that, he was trying to make an important point.
Probably the most quoted Albert Einstein quote. And you know what, maybe, even Albert Einstein, was wrong.

The great discoveries and thoughts have been by those that step outside the square so to speak....
Mainstream Science without Imagination and dreams will stagnate....
Imagination and dreams without mainstream knowledge and scientific research will stagnate as well...
They go hand in hand is what I am saying.
Another nice thought, but again, I'm not convinced it is completely true.

Sure, there have been some completely "outside of the box" theories that have been breakthroughs. But I am highly unconvinced it is always or completely true. Even such theories as Quantum Mechanics and Special Relativity have been built on the foundations of previous, often then-current work.

A.DIM
2013-Jan-04, 03:09 AM
Re: the "numbers" aspect of this thread: Planets Abound ... at least 100 hundred billion in our galaxy (http://phys.org/news/2013-01-planets-abound-astronomers-billion-populate.html).

Right then; this upward revision still does nothing insofar as copernican-mediocrity- cosmological principle and what it suggests.

Van Rijn
2013-Jan-04, 05:56 AM
The great discoveries and thoughts have been by those that step outside the square so to speak....


Not outside of mainstream scientific methodology, tested with objective evidence.



Mainstream Science without Imagination and dreams will stagnate....


Since I wasn't arguing against imagination, I don't see why you're bringing this up again. Imagination is great, but at best, it's just the starting point for science. Swift already covered this nicely:


As a working scientist for over 30 years (PhD in Chemistry) I have to disagree. Sure, imagination and dreaming is important, but it is not equal to knowledge. Science is fundamentally a data driven endeavor. It doesn't matter what you think if you cannot prove it.

Imagination is the starting point; then the really hard work begins to prove your idea.

ASTRO BOY
2013-Jan-04, 08:33 AM
Not outside of mainstream scientific methodology, tested with objective evidence.



Since I wasn't arguing against imagination, I don't see why you're bringing this up again. Imagination is great, but at best, it's just the starting point for science. Swift already covered this nicely:


If you read the relevant post of mine in its entirety, and any other post of mine you'll find I have never denigrated or been critical of mainstream science ever, only of those who think it can work by itself without Imagination and assumptions. My point is that Imagination logical assumptions and mainstream science are analogious to the divine trinity in Catholicism...they work together hand in hand.

My criticism is of the proposal that any part thereof can work in isolation when looking at the larger picture of course.

I commented on your comment re my comment that the hard nose straight down the line mainstream science by itself may have left us in the dark ages.

Again this is what I said......
" The great discoveries and thoughts have been by those that step outside the square so to speak....
Mainstream Science without Imagination and dreams will stagnate....
Imagination and dreams without mainstream knowledge and scientific research will stagnate as well...
They go hand in hand is what I am saying."

To be more to the point and closer to reality I should commence the statement with "Some of the" instead of just "The".

Selfsim
2013-Jan-04, 10:51 AM
IsaacKuo was referring to tests of technology (SETI radio and megastructure searches), NOT a test of biology.So if some technology was found floating around in space, it wouldn't be taken as inferring that some form of biology was ultimately at cause?
Are you kidding me .. you expect me to accept that?


Ask someone who made that argument. I pointed out that your claim that we can only test for Earth life is incorrect. That's like saying we couldn't test for exoplanets before the first discovery, or could only test for exoplanets that were identical to the planets in the solar system.

You are going well beyond the "we don't know" position, and instead claiming unreasonable restrictions on what can be tested. Man .. have you read anything I've written subsequent to post #136?

If, so I don't know what else I can do for you ...


Unfortunately, your arguments often seem to go beyond established facts onto dismissals from personal incredulity. Speaking of which, "sci-fi" is not a useful term in this context. There are many definitions of "sci-fi" and it isn't clear what you mean by the term (except that it generally seems to involve your personal incredulity regardless of physical plausibility). If you're unclear of what sc-fi is, then that would be your problem .. not mine.
You should spend some time to develop your own distinctions for it. (And report back to us, once you've sorted it out for yourself).


If you want to argue against an idea, show why it won't work by the science. Saying it is "sci-fi" or is "impractical" with no additional context is useless.

Incidentally, most of the science discussion on this board involves stuff that I used to read about in science fiction stories (like exoplanet discoveries, asteroid missions, Mars missions, now with a nuclear powered robot that shoots at rocks with it laser, Saturn missions with close-up views of the rings, and on and on).

This is everyday stuff, but all of it would have been incredible science fiction in my teenage years. So a comment about "sci-fi" (especially when you have provided no definition of what you mean by the term) isn't useful, and generally just looks like another dismissal from personal incredulity. Well, now I'm convinced you lack the distinctions necessary for distinguishing reality from fiction .. because you've just confirmed it in your own words ..

And, as usual you have not done your research before making your accusations. I have posted probably hundreds of posts explaining the reasons for what I say, all of which are based on empirical and/or theoretical science and mainstream philosophical logic. You just don't read 'em, or don't take the time to understand 'em, or whatever ...

By the way, I never had a problem with science fiction being 'incredible'. Your generalisation doesn't include me.


Except that you have dismissed future atmospheric studies of exoworlds for life studies, but I don't see where you have established why they must be excluded.We can barely diagnose unusual life here on Earth ... (and we're still finding more of it!)... diagnosis of life goes way, way beyond looking at bio-gases in atmospheres. Remote exo-atmospheric bio-gas detection over light year distances, cannot eliminate hitherto unknown, non-biological, non-Earth occuring (or even, some Earth-occuring natural processes).1 The uncertainties resulting from this, compromise being able to deduce 'Earth-like life' from atmospheric content2, (let alone non-Earth-like-life .... whatever that is!). Having said that, some exotic gases are known to be only produced artificially, (so far). If these were detected remotely, then what I say, would probably stand falsified, and I'm more than willing to see that happen, and there are many variables to consider before such a detection would seem 'plausible', in advance.

Footnotes:
1 This has been discussed frequently in this forum. This is not taken from 'personal incredulity'. I'll leave you to do the searching, if you already lack the knowledge ...
2 The only way to do that, is local sample testing, (also discussed previously) ... which is not feasibly executable over light year distances. If the test cannot be executed over such distances, (living reference samples are required), for reasons of practicality, then the diagnostic test is of little use to the hypothesis.

ASTRO BOY
2013-Jan-04, 08:53 PM
And, as usual you have not done your research before making your accusations. I have posted probably hundreds of posts explaining the reasons for what I say, all of which are based on empirical and/or theoretical science and mainstream philosophical logic. You just don't read 'em, or don't take the time to understand 'em, or whatever ...




I for one don't accept your reasons.


Science is what you know. Philosophy is what you don't know.
Bertrand Russell (1872-1970) English philosopher, mathematician.


[Science is] an imaginative adventure of the mind seeking truth in a world of mystery.
Sir Cyril Herman Hinshelwood (1897-1967) English chemist. Nobel prize 1956.