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Author Topic:   Abductive Reasoning In Science
Straggler
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Posts: 10333
From: London England
Joined: 09-30-2006


Message 1 of 120 (672177)
09-04-2012 1:33 PM


In this thread I want to get to grips with abduction and it's role in science. Here from the wiki page on Abductive Reasoning is a brief synopsis of what abduction entails in comparison to the more familiar inductive and deductive methods of reasoning:
Wiki writes:
Deduction allows deriving b from a only where b is a formal consequence of a. In other words, deduction is the process of deriving the consequences of what is assumed. Given the truth of the assumptions, a valid deduction guarantees the truth of the conclusion. For example, given that all bachelors are unmarried males, and given that this person is a bachelor, it can be deduced that this person is an unmarried male.
Induction allows inferring b from a, where b does not follow necessarily from a. a might give us very good reason to accept b, but it does not ensure b. For example, if all of the swans that we have observed so far are white, we may induce that the possibility that all swans are white is reasonable. We have good reason to believe the conclusion from the premise, but the truth of the conclusion is not guaranteed. (Indeed, it turns out that some swans are black.)
Abduction allows inferring a as an explanation of b. Because of this, abduction allows the precondition a to be abduced from the consequence b. Deduction and abduction thus differ in the direction in which a rule like "a entails b" is used for inference. As such abduction is formally equivalent to the logical fallacy affirming the consequent or Post hoc ergo propter hoc, because there are multiple possible explanations for b. For example, after glancing up and seeing the eight ball moving towards us we may abduce that it was struck by the cue ball. The cue ball's strike would account for the eight ball's movement. It serves as a hypothesis that explains our observation. There are in fact infinitely many possible explanations for the eight ball's movement, and so our abduction does not leave us certain that the cue ball did in fact strike the eight ball, but our abduction is still useful and can serve to orient us in our surroundings. This process of abduction is an instance of the scientific method. There are infinite possible explanations for any of the physical processes we observe, but we are inclined to abduce a single explanation (or a few explanations) for them in the hope that we can better orient ourselves in our surroundings and eliminate some of the possibilities.
In this thread I want to ask:
1) How widely is abductive reasoning used in science?
2) Is abductive reasoning a valid tool for science to use in formulating theories?
3) What are some key examples of abductive reasoning relevant to the sort of science topics regularly covered at EvC (Evolution, Big Bang, Age of earth etc. etc. etc.)?
4) Can we 'do science' without abductive reasoning? Or is it a vital component of the scientific method?

Replies to this message:
 Message 3 by RAZD, posted 09-04-2012 3:26 PM Straggler has replied
 Message 8 by Dr Adequate, posted 09-04-2012 6:03 PM Straggler has replied
 Message 14 by crashfrog, posted 09-06-2012 12:36 PM Straggler has replied
 Message 25 by Dr Jack, posted 09-06-2012 6:42 PM Straggler has not replied

  
Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 4 of 120 (672192)
09-04-2012 4:53 PM
Reply to: Message 3 by RAZD
09-04-2012 3:26 PM


Re: hypothesis
RAZD writes:
It's a valid way to get an hypothesis, and to develop tests that you could do to formalize it into theory.
This is where the verifiable/falsifiable predictions of a theory come in.
RAZD writes:
Curiously, I thought evolution was developed from deductive reasoning from examples where it is known to occur (likewise the original Theory of Natural Selection), am I wrong?
I think you are wrong. I think the theory of common ancestry was developed from the available evidence by means of a combination of deductive, inductive and abductive reasoning. I would suggest this is true of most scientific theories.
Can you explain how the theory that ALL life on Earth, including as yet undiscovered species, shares a common ancestor can be derived purely by a process of deductive logic?

This message is a reply to:
 Message 3 by RAZD, posted 09-04-2012 3:26 PM RAZD has replied

Replies to this message:
 Message 5 by RAZD, posted 09-04-2012 5:09 PM Straggler has replied

  
Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 6 of 120 (672200)
09-04-2012 5:30 PM
Reply to: Message 5 by RAZD
09-04-2012 5:09 PM


Re: hypothesis
RAZD writes:
I think you might be jumping the gun to theory (unless I read you wrong).
I am not suggesting that anything be described as a theory until the predictions (i.e. logical consequences deductively derived) have been tested to a reasonable degree.
For example we might abductively reason that some newly discovered species is part of the same tree of life as all other known life on Earth rather than something created ex-nihilo by magic (or whatever).
From this we would predict (using deductive reasoning) that the new species must share genetic make-up with other species on Earth. We can test this prediction through genetic analysis of the new species. Verification of this prediction doesn't disprove unfalsifiable notions of ex-nihilo creation. But it does allow us to confidently (albeit tentatively) discard such notions in favour of common descent. Right?
RAZD writes:
Now a logical conclusion - by whatever method - to me qualifies as an educated guess or conjecture.
Logic alone without testing by verifiable prediction - Sure.
But you have stated that the theory of evolution can be derived purely deductively (i.e. without either inductive or abductive reasoning components) have you not?
Question: Can you explain how the theory that ALL life on Earth, including as yet undiscovered species, shares a common ancestor can be derived purely by a process of deductive logic?

This message is a reply to:
 Message 5 by RAZD, posted 09-04-2012 5:09 PM RAZD has replied

Replies to this message:
 Message 7 by RAZD, posted 09-04-2012 6:01 PM Straggler has replied
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Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 9 of 120 (672213)
09-04-2012 6:18 PM
Reply to: Message 8 by Dr Adequate
09-04-2012 6:03 PM


Good post.
Dr A writes:
Being too stupid to understand the difference between these two modes of reasoning is of course part of the creationists' stock in trade.
I don't think it is limited to creationists. I think rampant demands for the disproof of things designed to be disprovable and relentless accusations of "illogical arguments" whenever non-deductive modes of reasoning are applied to the origins of various unfalsifiable concepts show that the confusion is rife in even those who should know better......

This message is a reply to:
 Message 8 by Dr Adequate, posted 09-04-2012 6:03 PM Dr Adequate has replied

Replies to this message:
 Message 12 by Dr Adequate, posted 09-04-2012 7:04 PM Straggler has replied

  
Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


(1)
Message 10 of 120 (672215)
09-04-2012 6:29 PM
Reply to: Message 7 by RAZD
09-04-2012 6:01 PM


Re: hypothesis
Straggler writes:
But you have stated that the theory of evolution can be derived purely deductively (i.e. without either inductive or abductive reasoning components) have you not?
RAZD writes:
Not really, just the initial hypothesis formation
Well I think you are still wrong. I think you are misunderstanding or under-estimating the role of abductive (and inductive) reasoning in the formation of scientific theories and hypotheses.
Can you explain how the hypothesis that ALL life on Earth, including as yet undiscovered species, shares a common ancestor can be derived purely by a process of deductive logic from the available evidence?
As I understand it deductive logic cannot go from the specific to the general. So I am intrigued as to how you think any theory/hypothesis involving a generalised statement can be deductively derived from specific observable instances.
I also think this misunderstanding on your part of the way scientific theories and hypotheses are developed lies at the heart of most of our disagreements........

This message is a reply to:
 Message 7 by RAZD, posted 09-04-2012 6:01 PM RAZD has replied

Replies to this message:
 Message 42 by RAZD, posted 09-07-2012 1:47 PM Straggler has replied

  
Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 13 of 120 (672311)
09-06-2012 12:22 PM
Reply to: Message 12 by Dr Adequate
09-04-2012 7:04 PM


Dr A writes:
Roughly speaking, when we compare the predictions of the theory to the evidence found in the present, we are being hypothetico-deductive, but when we reconstruct the past history of evolution from the evidence, we are performing abduction in the light of the theory.
A common creationist confusion along these lines pertains to dating, the geologic column and fossils. The creationist misunderstanding/complaint is based on thinking that fossils are dated by their position in the geologic column whilst the layers of the geologic column are dated by means of which fossils they contain.
There are instances where the age of something is abduced (is that the correct word) in terms of existing and accepted theory. But that is not how the original ages of these things was determined.

This message is a reply to:
 Message 12 by Dr Adequate, posted 09-04-2012 7:04 PM Dr Adequate has replied

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Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 23 of 120 (672324)
09-06-2012 4:03 PM
Reply to: Message 14 by crashfrog
09-06-2012 12:36 PM


Crash writes:
I'd like to get at what you mean by "valid." Logically valid?
In this thread I don't think it is for me to stipulate what is "valid" and what is not. There are those who might suggest that science is not a "valid" pursuit because it relies on methods and principles that are not deductively sound.
I would not agree with those people. But I would be interested to hear from them.
You seem to be suggesting that science isn't logically valid and that logic isn't scientifically valid. If that is the case I would suggest you are using too narrow-a-definition of what is "logically valid". But the point of this thread is to discus such issues in relation to abductive reasoning rather than for me to define "validity" from the beginning.

This message is a reply to:
 Message 14 by crashfrog, posted 09-06-2012 12:36 PM crashfrog has replied

Replies to this message:
 Message 26 by crashfrog, posted 09-06-2012 10:45 PM Straggler has replied
 Message 32 by Dr Adequate, posted 09-06-2012 11:53 PM Straggler has replied

  
Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 24 of 120 (672325)
09-06-2012 4:08 PM
Reply to: Message 21 by Blue Jay
09-06-2012 3:33 PM


Re: Abductive vs Inductive
BluJ writes:
So, you're not just extrapolating from a pattern, but you're actually trying to explain the pattern you've seen.
Based on a body of evidence and the predictive power of the theory in question having been previously verified we legitimately conclude that another example which fits said theory and it's predictions is explained by said theory.
The new data fits the pattern established by the theory so the theory is abductively concluded to apply to the new data.
Or something like that.....

This message is a reply to:
 Message 21 by Blue Jay, posted 09-06-2012 3:33 PM Blue Jay has replied

Replies to this message:
 Message 27 by Blue Jay, posted 09-06-2012 10:51 PM Straggler has replied

  
Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 38 of 120 (672351)
09-07-2012 8:27 AM
Reply to: Message 27 by Blue Jay
09-06-2012 10:51 PM


Affirming the Consequent
I think you are over-complicating matters.
Abductive reasoning in science is effectively about limiting explanations to those that have a record of success and tentatively discarding the infinite array of other possibilities until there is some evidential reason to think they might be relevant.
BluJ writes:
It sounds to me like abduction is just the action of proposing a hypothesis for a set of observations.
If you see a painting of unknown origin it is reasonable to abduce that the painting in question was painted by a human rather than something that popped into existence ex-nihilo, or which was created by an alien, or which was painted by a particularly artistic badger or.....etc. etc. etc. etc.
BluJ writes:
Your OP quote says abduction is equivalent to "affirming the consequent....
PREMISE: Humans have the capacity to produce paintings.
FACT: Exhibit A is a painting
CONCLUSION: Therefore exhibit A was produced by a human.
This is an example of affirming the consequent. In deductive logical terms it is fallacious. That humans have the capacity to produce paintings doesn't mean that ALL paintings are necessarily created by humans. So the conclusion is potentially false and does not deductively follow from the premise.
However given that we have no evidence of anything other than humans having created paintings (and lots of evidence that humans do create paintings) it is perfectly reasonable to abduce this deductively fallacious conclusion.
Having accused you of over-complicating things I fear I am now doing the same even more so.....
Edited by Straggler, : No reason given.

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Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 39 of 120 (672358)
09-07-2012 11:26 AM
Reply to: Message 26 by crashfrog
09-06-2012 10:45 PM


Philosophising Science
Crash writes:
I guess what I'm saying is that it's difficult to reconcile formal logic with empiricism or abduction. Or, for that matter, induction.
As has been pointed out by others - The reason for this is because deductive reasoning is not the same as abduction (or induction). They are different things.
Crash writes:
Many philosophers of science have construed this as a problem with empiricism and abduction - Hume's inductive fallacy, for instance.
Well that is a fair point. Philosophers of science (most notably Popper I believe) have wrestled with the whole issue of science incorporating modes of reasoning that don't result in deductive certainty. It's part of the whole thorny issue of "truth" and what exactly it is that science is telling us about the world.
The answers to these problems (in a simplistic nutshell) - Tentativity and verisimilitude.
Crash writes:
I choose to construe the issue as being a problem with logic, one that largely relegates logic to the status of an amusing parlor game as opposed to a useful tool for grappling with the world.
You go too far. Deductive logic is a crucial component of developing (and utilising) scientific theories. It just isn't the whole shebang!!

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Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 40 of 120 (672362)
09-07-2012 12:07 PM
Reply to: Message 32 by Dr Adequate
09-06-2012 11:53 PM


In this thread I don't think it is for me to stipulate what is "valid" and what is not.
Dr A writes:
Quite right. That's my job.
Well keep up the good work on that score.

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Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 41 of 120 (672367)
09-07-2012 12:29 PM
Reply to: Message 3 by RAZD
09-04-2012 3:26 PM


Wrong
RAZD writes:
Curiously, I thought evolution was developed from deductive reasoning from examples where it is known to occur (likewise the original Theory of Natural Selection), am I wrong?
Yes you are wrong.
Can you explain how the hypothesis that ALL life on Earth, including as yet undiscovered species, shares a common ancestor can be derived purely by a process of deductive logic from the available evidence?
You need to start understanding the role of different logical forms of reasoning if you are ever to understand science and how it actually works.

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Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 44 of 120 (672393)
09-07-2012 4:32 PM
Reply to: Message 42 by RAZD
09-07-2012 1:47 PM


Re: hypothesis
Ahhh. When in doubt pull out the Venn diagrams.....
RAZD writes:
Curiously, I thought evolution was developed from deductive reasoning from examples where it is known to occur (likewise the original Theory of Natural Selection), am I wrong?
Yes you are wrong.
Can you explain how the theory that ALL life on Earth, including as yet undiscovered species, shares a common ancestor can be derived purely by a process of deductive logic from the available evidence?
If you can't do this just say so.....

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Replies to this message:
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 Message 49 by RAZD, posted 09-07-2012 6:34 PM Straggler has replied

  
Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


(1)
Message 68 of 120 (672478)
09-08-2012 4:53 PM
Reply to: Message 49 by RAZD
09-07-2012 6:34 PM


Facts and Theories
RAZD writes:
Curiously, I thought evolution was developed from deductive reasoning from examples where it is known to occur (likewise the original Theory of Natural Selection), am I wrong?
Straggler writes:
Yes you are wrong. Can you explain how the theory that ALL life on Earth, including as yet undiscovered species, shares a common ancestor can be derived purely by a process of deductive logic from the available evidence?
RAZD writes:
I observe P to be true in case A
I observe P to be true in case B
...
I observe P to be true in case N (where N is the total number of observations involve)
Therefore I always observe P to be true (... so far).
No. You are conflating theory and fact. This does not come as any surprise to those of us aware of your track record on these matters.
That all observed and analysed instances of life on Earth are consistent with common descent is the data that supports the theory. It isn't the theory itself. Obviously. The theory is (tentatively) that ALL life on Earth, including as yet undiscovered species, share a common ancestor.
RAZD writes:
You will forgive me if I don't just take your - or anyone else's - word, but I'm willing to entertain an explanation of it.
It is not possible to derive a generalised conclusion from specific instances via deductive logic alone. Deductive logic can only ever tell you that which was contained in your starting assumptions/premises. It is a reductive process. Scientific theories are falsifiable generalised conclusions based on necessarily limited specific cases. Thus scientific theories cannot be derived by deduction alone. It just isn't possible by the very nature of science. Falsifiable and tentative as scientific theories are they necessarily contain non-deductive (i.e. inductive and abductive) components.
If you still think that the the theory that ALL life on Earth, including as yet undiscovered species, share a common ancestor: Can be derived deductively - Try again. This time try to bear in mind the difference between theories and the facts that support them.

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Straggler
Member
Posts: 10333
From: London England
Joined: 09-30-2006


Message 79 of 120 (672578)
09-09-2012 4:50 PM
Reply to: Message 77 by nwr
09-09-2012 3:49 PM


Re: Before Abductive, Inductive, or Deductive reasoning ...
Nwr writes:
There are some people who have tried sitting in the scientists labs. They are usually known as sociologists of science. An example of this is the work of Bruno Latour and Steve Woolgar. The sociologists of science come up with a rather different picture of science than the one that comes from academic philosophers.
I read your link. Interestingly it seems the studies you cite take specific observed cases of science in action and then generalise these findings to conclude that this is how science works......
It seems that inductive and abductive reasoning is alive and kicking in the sociology of science. How ironic.

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