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plant
2015-Sep-02, 09:45 AM
Hi all,

i have been pondering this for quite a while now.. delving into philosophical texts.. but i'm not sure i am getting anywhere. I posted some of this as a reply to another thread but it wasn't entirely on-topic.
i have the terrible feeling that i do not really understand what "science" is at all.... that the whole thing is built on foundations that only seem rock solid.

As i understand it.. (i could be wrong) re inductive vs deductive reasoning....

most people regard "science" along with Popper: you have to falsify a falsifiable hypothesis to add to knowledge.
In other words, you must 'reject' the null hypothesis.

e.g. Hypothesis: All Swans are White. This can never be proven. Every white swan you see makes no (or infinitesimal) difference.. but with a single sighting of a black swan one can reject the hypothesis.

What i can't quite get my head around- is that that not all hypotheses can be regarded as scientific as they cannot add to knowlege? e.g. Hypothesis: Kim Kardashian only looks good in jeans.

So- here are my questions:

1) on what 'scientific' basis do we select hypotheses as worthy of refuting? Do we rely on observation ? "Hmm.. looks like all swans are white... lets do a study". If so then our hypothesis selection criteria lie outside of science??
2) does the statement "Some swans are white" (after observing 1000 white swans) not tell us SOMETHING factual about reality? Would the statement "Some swans are white" be 'true' but "non-scientific?".
3) how does some 'scientific' knowledge e.g. "The mechanism of heredity in man is a double helix of DNA" fit into this? Whilst it is falsifiable.. e.g. if we happened to look down an electron microscope and find it was a triple helix.... are we rejecting the null hypothesis - or just 'confirming' by observation i.e. looking at just another white swan? Do we then just have to retrospectively put a 'negative' in front of the original assertion to make it "The mechanism of heredity in man is a triple helix" so we can look down a microscope, verify it is incorrect, and thus add to scientific knowledge?
4) are Popper's ideas on science as a falsifiable pursuit themselves scientific or non-scientific? Can one take this idea, and work out a way it could be proven false?

https://en.wikipedia.org/wiki/Falsifiability

malaidas
2015-Sep-02, 10:15 AM
Firstly, I would recommend for such an answer that you look into ' the last and final discussion of reality' as we are looking quite deeply into this topic as a formal part of the discussion.

Putting it in brief though. The problem is between absolutes and scientific thought. Science doesn't ponder what is, rather what works. Therefore when you look at it scientifically you don't worry about whether all swans are white, rather you observe and say that currently and contextually we conclude that those things we call swans are white, until such evidence arrives that would refute this theory. The the fact that philosophically such is non sequitur in that just because we have never seen a black swan doesn't mean there are non, is dealt with because science doesn't assert absolutes.

The key to falsification is not that there is some absolute correctness to it, rather it has been shown to be an effective way of determining what works.

plant
2015-Sep-02, 10:30 AM
hmm...
if you deny that Popper's demarcation is valid- then on what basis do you distinguish astrology from astronomy? religion from science? many people would say "religion works for me".
if you deny the problem of induction.. then why, for example, are clinical medical trials set up to disprove the null hypothesis?

malaidas
2015-Sep-02, 10:37 AM
I am trying desperately not to bleed over here from the other thread.

The difference is all in the method, all 'truths' depend on the process one chooses to arrive at them. Science is the most successful process for objective study currently known if your goals are to gain some kind of understanding of how things work. But it's still a choice to accept it

Eta: I do not deny the usefulness of such to the aims therefore, what I deny is a concept of some absolute truth being a part of science. Absolutes are for philosophers to wrangle over. As I said though, if you want to dissect the nature of science and reality there is a long standing and very active thread on the topic in this sub forum which is very bloated, but contains a lot of pertinent information to this question.

plant
2015-Sep-02, 11:38 AM
Hi Malaidas- i have tried to wade through the other thread... and whilst there is a lot there - it is not specifically about Popper's philosophy of science.
There is a separate discussion about instrumentalism vs realism... (which i really 'dig') and which i suppose is a non-scientific discussion about the REALITY or otherwise of physical constructs e.g. "The electron"...
And there has been recent stuff about whether mathematics itself is "scientific" i.e. whether it is falsifiable in a Popperian sense.. probably not.
I agree that (i think) Popper would say there is never any absolute truth - and that the "ERROR CORRECTION" method is what we call science.
In any case this thread was mainly about my potential misunderstanding or limited understanding of Popper...

malaidas
2015-Sep-02, 12:10 PM
The key point is that what popper says is that we cannot establish what us 'true' all we can do is establish what to our logic cannot be true

Ken G
2015-Sep-02, 01:20 PM
I agree that (i think) Popper would say there is never any absolute truth - and that the "ERROR CORRECTION" method is what we call science.
In any case this thread was mainly about my potential misunderstanding or limited understanding of Popper...I think it would help to start from the perspective that Popper was not trying to formalize science into some kind of mathematical structure, he was simply trying to understand how one could tell good science from bad science. He was motivated by the incredible success of Einstein's relativity, in contrast to the dubious success of various psychological theories that were coming out at the time. They both claimed to be science, they both claimed to help us understand observations, but Popper could tell there was an important difference, and he wanted to understand what that difference was. I would say that what he figured out centers on two principles: good science is "falsifiable," and good science makes "risky predictions". This means that to claim one is doing science, one must be able to show that one is making an honest effort to be proven wrong-- in contrast to a kind of sleight of hand where everything that happens can be interpreted as confirming evidence. This also means that one must not simply be explaining what is already known to be the case-- one must also be able to extend one's results to "risky" domains where the theory makes a specific prediction that is not already known to be true, and would not be expected to be true if not for the theory. If one looks for those two properties, I think it's pretty easy to tell good science from bad science or non-science.

Along the lines of science not being a formal pursuit, we should not imagine that its goal is to be able to assess the logical truthness or falseness of claims like "all swans are white." The actual goal of science is to be able to assess the value of the statement "I will gain conceptual and predictive power over swans by regarding them as white animals." Notice the key differences-- this is a statement that is tested by looking at the value of the proposition, not the absolute truth of the proposition. It also means that if we observe a black swan, we don't throw out the idea that "swans are white", we simply identify a new class of swan, the black swan, and we look for the reasons it fails to follow the rule. We are hoping to discover a new, more general rule about swans, but we can still regard swans as generally white-- we still gain power over swans by reacting to the fact that they are often white. So the scientific statement isn't "all swans are white", or "some swans are white", it is "the vast majority of swans are white." This is the statement that affords us with the predictive power over swans that we are looking for, without violating any observations of swans-- it's all about our goals for doing science.

Darrell
2015-Sep-02, 01:23 PM
Some things to consider. Despite the philosophical quandry, science is very effective. Popper is generally considered to be useful, but far from definitive. Science is not about proofs (in the maths sense), it is about probabilities. That is a key feature.

Regarding the swann example, if the parameter space has been sufficiently searched and no black swanns have been found then it has been sufficiently demonstrated that there are no black swanns to a high degree of probability, that nevertheless is not 100% and never will be. The "can't prove a negative" claim may be interesting to work with in philosophy but it is not an accurate depiction of reality. For any reasonable definition of the word proof, other than in maths, you certainly can prove a negative to a reasonably high level of confidence and that is done all the time. I can't prove, in the maths sense, that the sun will rise in the east tomorrow morning, but I can be confident enough to bet any sum of money on it. See Bayes Theorem for how probabilities of findings in science are typically calculated.

profloater
2015-Sep-02, 01:51 PM
If you actually read Popper, you find he describes how to form an hypothesis and how science builds towards a theory. He is clear about good strong theories which make strong predictions that can be tested. Basically a strong theory explains all previous observations and predicts a future experiment. A weak theory may explain what we see but offers no predictions. Often a key experiment can decide between two rival theories. Some theories like evolution and Darwin are good explanations but hard to test because difficult to rerun and separate variables. So Popper was tough on evolution, a good working hypothesis, but he did not know about epigenetics and so on.

Engineering offers a non philosophical procedure, you use what works, you play with metals till you get a strong steel and work with that. It has been suggested that we could have most of engineering without science, but electronics would not have developed in my opinion. If you compare the industrial revolution with religion as a brake, you can see science coming through as a rational way to understand the world etc.

Colin Robinson
2015-Sep-02, 01:58 PM
Some things to consider. Despite the philosophical quandry, science is very effective. Popper is generally considered to be useful, but far from definitive. Science is not about proofs (in the maths sense), it is about probabilities. That is a key feature.

Regarding the swann example, if the parameter space has been sufficiently searched and no black swanns have been found then it has been sufficiently demonstrated that there are no black swanns to a high degree of probability, that nevertheless is not 100% and never will be.

The probability that there are no black swans is far from 100%. In fact, it is zero percent, because we have black swans here in Australia.

Darrell
2015-Sep-02, 02:04 PM
Yeah, sure Colin. In the real world. The white swann problem is a hypothetical commonly used to demonstrate a problem. Look it up.

malaidas
2015-Sep-02, 06:49 PM
Hi Malaidas- i have tried to wade through the other thread... and whilst there is a lot there - it is not specifically about Popper's philosophy of science.
There is a separate discussion about instrumentalism vs realism... (which i really 'dig') and which i suppose is a non-scientific discussion about the REALITY or otherwise of physical constructs e.g. "The electron"...
And there has been recent stuff about whether mathematics itself is "scientific" i.e. whether it is falsifiable in a Popperian sense.. probably not.
I agree that (i think) Popper would say there is never any absolute truth - and that the "ERROR CORRECTION" method is what we call science.
In any case this thread was mainly about my potential misunderstanding or limited understanding of Popper...

In terms of the other threaf, popper comes up several times, but no its not specifically about popper. I read your question as being very similar in theme to what we are discussing there however.

Colin Robinson
2015-Sep-03, 01:29 AM
Hi all,

i have been pondering this for quite a while now.. delving into philosophical texts.. but i'm not sure i am getting anywhere. I posted some of this as a reply to another thread but it wasn't entirely on-topic.
i have the terrible feeling that i do not really understand what "science" is at all.... that the whole thing is built on foundations that only seem rock solid.

As i understand it.. (i could be wrong) re inductive vs deductive reasoning....

most people regard "science" along with Popper: you have to falsify a falsifiable hypothesis to add to knowledge.
In other words, you must 'reject' the null hypothesis.

e.g. Hypothesis: All Swans are White. This can never be proven. Every white swan you see makes no (or infinitesimal) difference.. but with a single sighting of a black swan one can reject the hypothesis.


Popper's concept of falsifiability is not applicable to all scientific statements. It is applicable to hypotheses about universal laws of nature. For instance, Newton's theory of universal gravitation.


1) on what 'scientific' basis do we select hypotheses as worthy of refuting? Do we rely on observation ? "Hmm.. looks like all swans are white... lets do a study". If so then our hypothesis selection criteria lie outside of science??

Observation is certainly part of science, not outside of science. However, it is not the same thing as a hypothesis about a universal law of nature. To be worthy of refuting, a hypothesis about a universal law has to be consistent with past observations.


2) does the statement "Some swans are white" (after observing 1000 white swans) not tell us SOMETHING factual about reality? Would the statement "Some swans are white" be 'true' but "non-scientific?".

The statement is both true and scientific. However it is not a hypothesis about a universal law.


3) how does some 'scientific' knowledge e.g. "The mechanism of heredity in man is a double helix of DNA" fit into this? Whilst it is falsifiable.. e.g. if we happened to look down an electron microscope and find it was a triple helix.... are we rejecting the null hypothesis - or just 'confirming' by observation i.e. looking at just another white swan? Do we then just have to retrospectively put a 'negative' in front of the original assertion to make it "The mechanism of heredity in man is a triple helix" so we can look down a microscope, verify it is incorrect, and thus add to scientific knowledge?

This statement is more general than "some swans are white", but doesn't have the hypothesised universal character of Newton's theory of gravity... If you looked down an electron microscope at a sample of human cells, and found a triple helix instead of a double one, then yes, that would falsify the statement that all human beings keep their genetic information in a double helix.


4) are Popper's ideas on science as a falsifiable pursuit themselves scientific or non-scientific? Can one take this idea, and work out a way it could be proven false?

Philosophy of science is a valid field of enquiry, but it is a different field from science itself. Hence we cannot expect its concepts to be falsifiable in the same way.

plant
2015-Sep-03, 07:22 AM
Thanks for your replies....
I've been thinking about it from the point of view of Nassim Taleb's thanksgiving turkey.
20946
Let's say the Turkey is trying to work out scientifically what's going to happen in his life.
Does each happy day confirm the next will also be a happy day? This is the problem of induction.
Based on what you're saying Ken .. (i think- please forgive me if i have got the wrong end of the stick) is that yes... the Turkey could/should develop a 'scientific theory' that every day is going to be great- based on the previous day's experience.
You could forgive the Turkey for saying ""I will gain conceptual and predictive power over my life" by regarding the past as predictive of the future.
I think Popper would say it tells you very little. I think perhaps not only does a theory need to be FALSIFIABLE... it also NEEDS to actually BE FALSIFIED for scientific knowledge to progress. Only when the turkey is led to the chopping block does he learn that his null hypothesis has been negated.... in his final moments he will learn a scientific truth about his life.

grapes
2015-Sep-03, 07:44 AM
As i understand it.. (i could be wrong) re inductive vs deductive reasoning....

most people regard "science" along with Popper: you have to falsify a falsifiable hypothesis to add to knowledge.
In other words, you must 'reject' the null hypothesis.

I'm going to reject that statement completely.

I'm pretty sure Popper didn't say it that way too. Scientific hypotheses are falsifiable, according to Popper, but they don't have to be falsified to add to knowledge. Luis Alvarez not withstanding (he refered to those who verified scientific hypotheses step by step as "stamp collectors"), verifying hypotheses does add to knowledge--you seem to be taking it to the infinite limit ("infinitesimal").


e.g. Hypothesis: All Swans are White. This can never be proven. Every white swan you see makes no (or infinitesimal) difference.. but with a single sighting of a black swan one can reject the hypothesis.

What i can't quite get my head around- is that that not all hypotheses can be regarded as scientific as they cannot add to knowlege? e.g. Hypothesis: Kim Kardashian only looks good in jeans.

For instance, that link (wiki falsifiability) has this distinction:


For example, while "all men are mortal" is unfalsifiable, it is a logical consequence of the falsifiable theory that "every man dies before he reaches the age of 150 years".

malaidas
2015-Sep-03, 08:01 AM
Yes, the process of science is such that, (in theory) any scientific theory is but one observation from being overturned. Of course in practice this seldom happens to those that are well established. Rather we are forced to accept that such a theory is not universal, it has an operational domain.

There are several common examples one can use to see this, but gravity is perhaps the most immediately obvious to use on this forum. Specifically Newtonian gravity. Technically Einstein refuted this theory, because he showed that it wasn't universal. That however hasn't stopped it being used widely by science where it does hold.

This is where some overlap is unavoidable but the question is now what does this mean in a philosophical sense. I will sidestep MDR and simply look at the nature of practical science. There are a few key points to note

1) science does not need some fundamental standard of correctness, it needs only things that work.

2) science may seek unified laws but it doesn't need them. Indeed we seek them for philosophical rather than scientific reasons. It's purely for aesthetic reasons in our sense making.

3) science in practice can only answer certain types of questions, it is limited by the goals which define the process. Also those answers depend upon that process.

4) that science does not and must not deal in absolutes, an absolute is the closure of enquiry and that never happens for a scientific theory. Good science is done with a reasonable measure of scepticism. This is one huge difference to other forms of knowledge

When you consider these 4 points one can begin to see a picture of just why science works. Despite it not sitting on a completely solid foundation. Truth is as humans we have no solid foundation except if we choose to believe in things creating such as personal certainties, which no one else is forced to accept. Instead science creates a contextual and provisional picture that appears to match what we observe and which gives us predictive power and thus a measure of control over the world we experience. It doesn't tell us what is in a philosophical sense, nor why things are as they are etc. Rather it provides a useful form of inductive reasoning which says, given these conditions we will experience this.

ETA: indeed we can take this quite a bit further, in recognising the kind of thinking that we could describe as scientific. There is a pragmatism absent from other methods, that has breathed life into it and allowed it to progress. This pragmatism depends upon our being sceptical of absolutes and also in seeing how utterly irrelevant they are to us. Our foundation becomes our observation of a given models etc success, or lack of and in always being ready to change our minds about things, including the process itself. We construct a picture of how things work, that works for us and its measure of correctness is how well it works relative to other notions in matching our goals. The critical point though is that we have seen that no solid fixed foundation of correctness is needed. This allows things like falsification to work, without getting tied up over philosophical niggles. It allows as Darrel said us to work purely in terms of probabilities, but those probabilities apply to our inductive reasoning, in that we are predicting that this theory will likely keep on matching our observations which is our goal. It allows us to use simplicity and idealisation without any concern, because of the nature of sciences goals.

Finally please note that this describes scientific thinking, it doesn't necessarily describe the thinking of scientists all of the time. As scientists are Human, so the above idealisation doesn't universally apply. We all hold non scientific beliefs to one degree or another. We all to one extent or another seek a foundation more solid than this into which we feed science and establish our world view. But such are personal concerns.

Ken G
2015-Sep-03, 01:44 PM
Let's say the Turkey is trying to work out scientifically what's going to happen in his life.
Does each happy day confirm the next will also be a happy day?I'd say the problem here is what I mentioned above, and malaidas just expounded on in more detail, is that science is not looking for absolutes like "tomorrow will be happy," or "tomorrow the Sun will rise", or "things fall when you let go of them." Those are essentially platitudes, not laws! The key thing that science does, that essentially no other human endeavor seeks to do, is to dig deeply into its "truths." That's the heart of "falsifiability", it's not that we have to falsify things, it's that we have to be trying to falsify things-- we have to dig into what we think is true to look for when it isn't. So a scientific turkey is never content to say "all my yesterdays were great, so tomorrow will be also, pay no attention to the guy sharpening the axe." Instead, the scientific turkey asks, "why were all my yesterdays so good, and is there anything different going on today that might herald a change in that situation, like that guy sharpening the axe?" Science does not just seek platitudes like "the Sun will rise tomorrow", it is a study of changes-- it asks, why does the Sun rise, and what could make that not happen?

That's what science asks, and it finds answers by creating models, and testing them. No scientist worth their salt says "the full Moon looked a certain way each month for the last decade, so it will this month also", instead they say "let us account for that observation by modeling the Moon as a sphere that is lit up on one side as it goes around the Earth, and since that light comes from the Sun, if the Earth is in the way, the shadow of the Earth can change the appearance of the full Moon, so let us try to figure out when the full Moon will not look like it did last month, and let us test the prediction, rather than the platitude." Science seeks to model the how, not just the what, and that is the heart of falsification because the models tell us what to look for that could falsify our current picture of how things work. That's the other side of Popper's coin: the "risky" prediction. It's not at all "risky" to say the full Moon will look like it did every month for the last year, but it is very risky to say that next month, the full Moon will look very different, based on a model of its motion and the reasons why it looks the way it does.


You could forgive the Turkey for saying ""I will gain conceptual and predictive power over my life" by regarding the past as predictive of the future.That is true, but it's not the whole story either-- the Turkey is being scientific to expect a "good" day tomorrow, but it is not being scientific if it stops there. It must also seek to model what is going on that is giving it those good days, and what could change that, otherwise its predictions should be expected to be only partially successful. Its final discovery might be "when the farmer sharpens his axe, I might not have a good day", and that is the kind of fine tuning that happens in scientific thinking. So the bottom line is, science does look for unification and simplification when it makes its models, but it does not look for sweeping generalizations without explanation. That's why it looks for models in the first place, because models do more than explain what has been seen, they make testable predictions that can guide you to the necessary corrections to your model. And our models are constantly being corrected, just like the turkey's!

Of course, if the models are really good, they may have a "universal" character, but even "universal" laws (such as Newton's universal law of gravitation) should not be looked at as scientific platitudes, they should be looked at as theories that may need correction or replacement in specific situations that we are always trying to discover. Laws were made to be broken, and the scientist never stops seeking out the conditions under which a law fails. So to summarize, we should not say we only learn when we falsify, but we should definitely say that we cease learning when we cease trying to falsify.

The reason this is so important to understand is that there is a widespread misconception that science seeks to "explain everything", or find a "theory of everything." This is totally untrue, it is quite clear from the history of the endeavor of science that this would be a futile and unnecessary way to frame its goals. The second the scientist says "now I have the theory of everything", they have ceased being a scientist. A better model is to realize that scientific knowledge is like the interior of a sphere, whose surface is a boundary to the unknown, and as the sphere increases in size, the boundary only gets bigger. Perhaps the size of the unknown boundary shrinks in comparison to the size of the known interior as both grow, but the absolute size of that unknown boundary only ever grows. There is no more evidence of an "ultimate edge" to this sphere than there is evidence of an edge to the universe itself, and that is all the turkey is discovering.

plant
2015-Sep-04, 03:31 AM
No scientist worth their salt says "the full Moon looked a certain way each month for the last decade, so it will this month also", instead they say "let us account for that observation by modeling the Moon as a sphere that is lit up on one side as it goes around the Earth, and since that light comes from the Sun, if the Earth is in the way, the shadow of the Earth can change the appearance of the full Moon, so let us try to figure out when the full Moon will not look like it did last month, and let us test the prediction, rather than the platitude.

..i suppose this is a separate issue but isn't this exactly what a lot of people here (the 'instrumentalists') say about quantum physics?

I'm not diagreeing with you.. and appreciate the responses... just trying to see where Popper fits into the modern philosophy of science.... as i see it most philosophy is equivalent to religion.. but i think 'scientists' or those interested in science need to understand the philosophy of science.... something i am struggling with!

Ken G
2015-Sep-04, 04:16 AM
No scientist worth their salt says "the full Moon looked a certain way each month for the last decade, so it will this month also", instead they say "let us account for that observation by modeling the Moon as a sphere that is lit up on one side as it goes around the Earth, and since that light comes from the Sun, if the Earth is in the way, the shadow of the Earth can change the appearance of the full Moon, so let us try to figure out when the full Moon will not look like it did last month, and let us test the prediction, rather than the platitude.

..i suppose this is a separate issue but isn't this exactly what a lot of people here (the 'instrumentalists') say about quantum physics?I don't know what you mean, it seems to me the instrumentalists say "how can we model the system our instrument is measuring to see when it will do such-and-such, and when it won't." It's just what I'm talking about. What you are saying is nothing more than "the electrons made an interference pattern last time, so they will again this time, never mind how the setup may have changed." How would that ever show up in a science book? Science is about modeling, and the model also tells you under what circumstances to expect the interference pattern to be different if the setup is at all different-- and that's true even for instrumentalists.

.... as i see it most philosophy is equivalent to religion.. but i think 'scientists' or those interested in science need to understand the philosophy of science.... something i am struggling with!Philosophy is a lot different from religion, because philosophy starts with metaphysical principles, and studies their logical ramifications. Religion doesn't generally make use of logic, though there are religious philosophers. However, philosophy generally does ask for belief in the principles, just as religion asks for beliefs in the tenets of the religion. Philosophy does use testing to some degree, in the sense that it "tests" that the logical ramifications of its principles make sense and are desirable. When one talks about a "test of faith" in religion, one generally does not mean a test of whether the faith is working, it usually means the opposite-- can you hold the faith even if it appears to not be working. So each has a very different character, but there are always connections and crossovers.

plant
2015-Sep-04, 02:19 PM
thanks for all your replies.. i print them off, sit under a tree and ponder them.
(spring in the southern hemisphere)

profloater
2015-Sep-04, 09:15 PM
And oft I wandered to the philosophers tent
And departed from the same door as in I went

( adapted slightly from Omar Khyam)

But I maintain you are on the right path to read Popper, and not just summaries of Popper in WP ; he writes clearly.

plant
2015-Sep-05, 01:15 AM
Brilliant!
It is all very "In-Tents"

Ken G
2015-Sep-05, 04:47 AM
Maybe we shouldn't scoff-- the philosopher's tent apparently has a door in it, now that's someone who knows something about how to live!