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Author Topic:   Induction and Science
Straggler
Member
Posts: 10284
From: London England
Joined: 09-30-2006


Message 661 of 744 (593577)
11-27-2010 8:10 PM
Reply to: Message 659 by RAZD
11-27-2010 7:34 PM


Re: induction vs deduction elements
RAZD writes:

Based on the evidence of A that is B, we deduce that all A is B.

Deduce?

IF some THEN all.

Surely this is inductive?

Wiki on Inductive Reasoning writes:

Inductive reasoning, also known as induction or inductive logic, or educated guess in colloquial English, is a kind of reasoning that draws generalized conclusions from a finite collection of specific observations. The premises of an inductive logical argument indicate some degree of support (inductive probability) for the conclusion but do not entail it; that is, they suggest truth but do not ensure it.

Induction is employed, for example, in the following argument:

All of the ice we have examined so far is cold. (Specific observations)
Therefore, all ice is cold. (Generalized conclusion) Link

How is this not exactly what you are doing?

Edited by Straggler, : No reason given.


This message is a reply to:
 Message 659 by RAZD, posted 11-27-2010 7:34 PM RAZD has responded

Replies to this message:
 Message 665 by RAZD, posted 11-27-2010 11:22 PM Straggler has responded

  
Stephen Push
Member (Idle past 2939 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 662 of 744 (593582)
11-27-2010 8:29 PM
Reply to: Message 656 by RAZD
11-27-2010 5:36 PM


Re: induction vs deduction elements
Welcome to the fray, RAZD.

RAZD writes:

Let's say we have tested all the elements in A and find that every one has the elements of B as well.

Based on the evidence of A that is B, we deduce that all A is B. This predicts that any new A will also be B.

Any A that is notB invalidates the concept
Any A that is B expands the area covered by A, but does not confirm that all A is B (there could be A outside B in the diagram).

If there could be A outside B in the diagram, then "all A is B" would be an induction, not a deduction.

Based on the absence of any evidence of any B that is notA, we can, by inductive logic, extend that conclusion to the possibility that all B is A, and then use that to formulate testing of that concept.

Any B that is notA invalidates the concept
Any B that is A expands the area covered by A, but does not confirm that all B is A.

Since "all A is B" is based on induction, I don't see any logical difference between that conclusion and the conclusion "all B is A."

I second Panda's request for a real-world example. I believe the hypothetical you have introduced is different from the types of problems generally encountered in science. In the real world, we wouldn't be able to study every A and every B. We wouldn't even know whether the elements of A and B that we measured are all of the elements that exist.

Personally I think it is a weaker stance, being more of a "best guess" than a logical conclusion.

Science often uses inference to the best explanation (IBE), which is a non-deductive method. For example, Darwin used IBE when he marshaled information about many plants and animals to make the case for common descent.


This message is a reply to:
 Message 656 by RAZD, posted 11-27-2010 5:36 PM RAZD has acknowledged this reply

  
Stephen Push
Member (Idle past 2939 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 663 of 744 (593591)
11-27-2010 9:47 PM
Reply to: Message 659 by RAZD
11-27-2010 7:34 PM


Re: induction vs deduction elements
Thanks for the real-world example, RAZD.

RAZD writes:

All dogs are observed to be canines
All canines are observed to be mammals
A new (species) is observed to be a dog subspecies

Deductive conclusion\prediction:

Any new dog species will still be a canine
Any new canine species will still be a mammal

That is technically a deductive argument, but it conceals a lot of non-deductive work. The first two lines of your syllogism rely on the work done by Darwin and others -- using the non-deductive IBE method -- to establish the theory of evolution. To know whether the third line is true, scientists would have to use IBE to determine where this new animal fits into the tree of life.

After non-deductive methods have done all of the heavy lifting, the remaining deductive argument is trivial.

Conversely the inductive conclusion\prediction:

Any new canine species will be a dog
Any new mammal species will be a canine

While it is possible that the new mammal species would be a dog\canine, this is a much weaker prediction than that a new dog species will be a canine\mammal.

Rather than a "best guess," that sounds like a shot in the dark. I find it hard to imagine how such a line of reasoning could be useful in actual scientific research.


This message is a reply to:
 Message 659 by RAZD, posted 11-27-2010 7:34 PM RAZD has responded

Replies to this message:
 Message 664 by RAZD, posted 11-27-2010 11:01 PM Stephen Push has responded

  
RAZD
Member
Posts: 19759
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 5.8


Message 664 of 744 (593592)
11-27-2010 11:01 PM
Reply to: Message 663 by Stephen Push
11-27-2010 9:47 PM


Re: induction vs deduction elements
Hi Stephen Push, thanks.

That is technically a deductive argument, but it conceals a lot of non-deductive work. The first two lines of your syllogism rely on the work done by Darwin and others -- using the non-deductive IBE method -- to establish the theory of evolution. To know whether the third line is true, scientists would have to use IBE to determine where this new animal fits into the tree of life.

Darwin et al:

  1. selection in isolated domesticated animals leads to variations that are noticeably different from wild populations.
  2. selection in the wild occurs through natural differences in breeding success and survival success
    ∴ selection in the wild can lead to variations that are noticeably different in isolated population

That current known dogs are canines is an observed fact of common ancestry, not an inductive conclusion.
That current known canines are mammals is an observed fact of common ancestry, not an inductive conclusion.

Of course, part of this is that the definition of canine includes dogs and the definition of mammals includes canines.

Rather than a "best guess," that sounds like a shot in the dark. I find it hard to imagine how such a line of reasoning could be useful in actual scientific research.

Indeed it seems very weak in this example, because we know of mammals that are not canines and canines that are not dogs. When we have conditions where we have no such contradictory evidence there is a possibility that can be tested and that can lead to falsification.

Enjoy.


we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

This message is a reply to:
 Message 663 by Stephen Push, posted 11-27-2010 9:47 PM Stephen Push has responded

Replies to this message:
 Message 666 by Stephen Push, posted 11-28-2010 1:34 AM RAZD has responded

  
RAZD
Member
Posts: 19759
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 5.8


Message 665 of 744 (593595)
11-27-2010 11:22 PM
Reply to: Message 661 by Straggler
11-27-2010 8:10 PM


Re: induction vs deduction elements
Hi Straggler, my apologies.

IF some THEN all.

You are correct, I should have said that we conclude that all tested A is B.

How is this not exactly what you are doing?

The deductive part is the confirmation of the foundational evidence for an hypothesis being consistent with the hypothesis.

All tested A are also B.

From there you make inductive guesses on what testing will show. When such testing is done, then deductive logic will determine whether or not the concept is invalidated.

Enjoy.


we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

This message is a reply to:
 Message 661 by Straggler, posted 11-27-2010 8:10 PM Straggler has responded

Replies to this message:
 Message 668 by Straggler, posted 11-28-2010 6:00 AM RAZD has responded

  
Stephen Push
Member (Idle past 2939 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 666 of 744 (593601)
11-28-2010 1:34 AM
Reply to: Message 664 by RAZD
11-27-2010 11:01 PM


Re: induction vs deduction elements
RAZD writes:

Darwin et al:

  1. selection in isolated domesticated animals leads to variations that are noticeably different from wild populations.
  2. selection in the wild occurs through natural differences in breeding success and survival success
    ∴ selection in the wild can lead to variations that are noticeably different in isolated population

In my opinion, that is an eminently sound bit of reasoning. But it is not deductive, because the conclusion is not a necessary consequence of the premises.

That current known dogs are canines is an observed fact of common ancestry, not an inductive conclusion.
That current known canines are mammals is an observed fact of common ancestry, not an inductive conclusion.

As I said in my previous post, your dog-canine-mammal syllogism is deductive. But it is not very helpful because it presupposes common decent, a concept which I believe was developed largely by non-deductive means. If we were to presuppose special creation rather than common decent, it would not be an observed fact that dogs are canines or that canines are mammals.

Of course, part of this is that the definition of canine includes dogs and the definition of mammals includes canines.

Precisely. It is a true but trivial deduction.

That's not to say that I deny the value of deduction in science. Deduction is useful in deriving testable hypotheses from theories. Mathematical deduction is useful in models and statistical analysis.

Edited by Stephen Push, : No reason given.

Edited by Stephen Push, : No reason given.


This message is a reply to:
 Message 664 by RAZD, posted 11-27-2010 11:01 PM RAZD has responded

Replies to this message:
 Message 670 by RAZD, posted 11-28-2010 9:16 AM Stephen Push has responded

  
anglagard
Member
Posts: 2185
From: Socorro, New Mexico USA
Joined: 03-18-2006


Message 667 of 744 (593604)
11-28-2010 4:08 AM
Reply to: Message 654 by crashfrog
11-27-2010 3:05 PM


Re: A general comment
crashfrog writes:

We could, if you wanted, but I think my views have tempered somewhat - I'm prepared to accept that at least some people are engaged in real empiricial science in the field of economics. I'm still of the opinion that economics is primarily a way for people to identify as partisan in the supposedly non-partisan academic arena, but I've come to accept that at least some economists are genuinely interested in solving problems in a scientific way.

If you have an interesting challenge to that view, I'm prepared to talk about it.

Sheeet, my opinion of your posts (which was never low to begin with) just jumped a few thousand percent.

Please carry on and keep up the good work!


The idea of the sacred is quite simply one of the most conservative notions in any culture, because it seeks to turn other ideas - uncertainty, progress, change - into crimes.
Salman Rushdie

This rudderless world is not shaped by vague metaphysical forces. It is not God who kills the children. Not fate that butchers them or destiny that feeds them to the dogs. Its us. Only us. - the character Rorschach in Watchmen


This message is a reply to:
 Message 654 by crashfrog, posted 11-27-2010 3:05 PM crashfrog has not yet responded

    
Straggler
Member
Posts: 10284
From: London England
Joined: 09-30-2006


Message 668 of 744 (593620)
11-28-2010 6:00 AM
Reply to: Message 665 by RAZD
11-27-2010 11:22 PM


Re: induction vs deduction elements
RAZD writes:

You are correct, I should have said that we conclude that all tested A is B.

Then you haven't deduced anything. You have simply gone in a circle and ended up back where you started. I.e. with your observation that all thus far observed instanced of A are B.

RAZD writes:

The deductive part is the confirmation of the foundational evidence for an hypothesis being consistent with the hypothesis.

It would be a very crap hypothesis if it wasn'y even in accordance with the evidence from which is was founded wouldn't it?

RAZD writes:

From there you make inductive guesses on what testing will show.

Our inductive "guesses" reliably (but tentativley - i.e. without absolute certainty) tell us that the laws of thermodynamics are universal and that perpetual motion machines are impossible.

Do you really think this is a guess?


This message is a reply to:
 Message 665 by RAZD, posted 11-27-2010 11:22 PM RAZD has responded

Replies to this message:
 Message 669 by RAZD, posted 11-28-2010 8:40 AM Straggler has responded

  
RAZD
Member
Posts: 19759
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 5.8


Message 669 of 744 (593637)
11-28-2010 8:40 AM
Reply to: Message 668 by Straggler
11-28-2010 6:00 AM


Re: induction vs deduction elements
Hi Straggler,

Then you haven't deduced anything. You have simply gone in a circle and ended up back where you started. I.e. with your observation that all thus far observed instanced of A are B.

Not really - the deduction is the formalization of the evidence in such a way that it leads to the hypothesis.

Observes that some known evidence is A
Selects the evidence that is A
Observes that the selected evidence is B
Concludes that all tested A is B

The hypothesis is then formed as follows

All tested A is B
IF this pattern holds for all A
THEN all A is B

Test to see if the pattern holds.

If A is found that is notB then P2 is false and the conclusion is falsified, by deductive logic.

Do you really think this is a guess?

Do you know the difference between "best (or educated) guess" and just "guess"? Or do you think this is "just a theory"?

Enjoy.


we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

This message is a reply to:
 Message 668 by Straggler, posted 11-28-2010 6:00 AM Straggler has responded

Replies to this message:
 Message 671 by Straggler, posted 11-28-2010 9:44 AM RAZD has responded

  
RAZD
Member
Posts: 19759
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 5.8


Message 670 of 744 (593640)
11-28-2010 9:16 AM
Reply to: Message 666 by Stephen Push
11-28-2010 1:34 AM


Re: induction vs deduction elements
Hi Stephen Push,

... But it is not very helpful because it presupposes common decent, a concept which I believe was developed largely by non-deductive means.

Really? The fact remains that common descent is highly tested, and has not yet been falsified for a single species. As such, it is not "presupposed" but evidence based and a highly tested theory.

In this experiment wild foxes were bred into dog-like foxes, but they are still foxes by common descent:
http://cbsu.tc.cornell.edu/ccgr/behaviour/Index.htm

No presupposition there.

If we were to presuppose special creation rather than common decent, it would not be an observed fact that dogs are canines or that canines are mammals.

Which, in essence, falsifies special creation, via deductive logic, as we see that they (a) are canines (posses the characteristics of canines), (b) are mammals (posses the characteristics of mammals), and (c) bear the evidence of common descent in DNA and fossil records. If you know of a dog that is not a canine or not a mammal, then let me know.

Presupposition is a bad way to do science, because it is not based on evidence but on wishing based on opinion. Unfortunately, for presuppositionists, opinion has little effect on reality.

If we presupposed (guessed without evidence) that speciation only occurs during a full moon, then we would expect to see speciation occur only during full moons: we don't, so that presupposition is falsified.

Enjoy.


we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

This message is a reply to:
 Message 666 by Stephen Push, posted 11-28-2010 1:34 AM Stephen Push has responded

Replies to this message:
 Message 682 by Stephen Push, posted 11-28-2010 11:28 PM RAZD has acknowledged this reply

  
Straggler
Member
Posts: 10284
From: London England
Joined: 09-30-2006


Message 671 of 744 (593644)
11-28-2010 9:44 AM
Reply to: Message 669 by RAZD
11-28-2010 8:40 AM


Re: induction vs deduction elements
RAZD writes:

All tested A is B
IF this pattern holds for all A
THEN all A is B

Test to see if the pattern holds.

If A is found that is notB then P2 is false and the conclusion is falsified, by deductive logic.

And if it isn't falsified after a great deal of testing? Can we at any point inductively (but tentativley) conclude that all A is B with confidence?

For example can we confidently (but tentatively) conclude that there is no such thing as a perpetual motion machine?

RAZD writes:

Do you know the difference between "best (or educated) guess" and just "guess"? Or do you think this is "just a theory"?

It was you that used the phrase "inductive guess". The question is do you understand that universal principles and scientific conclusions (such as that ALL species on Earth are derived from a common ancestor) no matter how well tested are necessarily inductive to some degree?

Panda writes:

By definition: you cannot make general/universal rules/laws using deductive reasoning.

Do you disagree with the above?

AbE - I think that your position on inductive reasoning (whether you yet realise it or not) lies at the heart of Mod's accusation that by the terms of your argument "Science is pseudoskeptical" Message 498

Edited by Straggler, : No reason given.


This message is a reply to:
 Message 669 by RAZD, posted 11-28-2010 8:40 AM RAZD has responded

Replies to this message:
 Message 672 by RAZD, posted 11-28-2010 1:59 PM Straggler has responded

  
RAZD
Member
Posts: 19759
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 5.8


Message 672 of 744 (593676)
11-28-2010 1:59 PM
Reply to: Message 671 by Straggler
11-28-2010 9:44 AM


Re: induction vs deduction elements
Hi Straggler,

And if it isn't falsified after a great deal of testing? Can we at any point inductively (but tentativley) conclude that all A is B with confidence?

Um, we can never reach a deductive conclusion that all A is B without testing all A, as that would be making an unwarranted assumption.

Yes you can reach a high degree of confidence that a theory is (tentatively) correct, but you cannot make the final claim that it is true.

But a high degree of confidence that all A is B, does not mean that it is highly likely that all A is B -- the first is opinion, and the second is (properly) a result of evaluation of all the possibilities, many of which may be unknown and therefore impossible to evaluate.

One thing that must be considered is that the falsification tests used may not be properly\completely testing the hypothesis, and that another falsification test will be developed and end up falsifying the concept.

Panda writes:

By definition: you cannot make general/universal rules/laws using deductive reasoning.


Do you disagree with the above?

I would agree that you cannot make inductive conclusions using deductive reasoning.

I would agree that you can never make the deductive conclusion that all A is B without evidence that all A is in fact B.

I would agree that any "general/universal rule/law" conclusion that can be reached by deductive logic would be called a fact.

Without reaching the level of fact, the closest you can get is having a high degree of confidence that all A is likely to be B, but never get to the point of concluding all A is B without evidence that all A is in fact B, and this in inherent in the formation due to the IF statement:

All tested A is B
IF this pattern holds for all A
THEN all A is B

Only if all A is tested and found to be B can we reach a deductive conclusion that all A is B, and this state is relatively unlikely to occur for many conditions, but when it does then the result is regarded as fact (all A become all tested A) rather than a "general/universal rule/law".

But all it takes is one A that is notB to reach the deductive conclusion that not all A is B, as the concept of all A is B has been falsified by contrary evidence.

Inductive logic can lead to testing, but the end result must be evaluated by deductive logic based on, and supported by, evidence.

To properly form a scientific theory you start by evaluating known evidence (A) and deduce some trait that is common to all the known evidence (is B). Then you generalize by induction to make predictions of what you would see if the hypothesis were true and what you would see if the hypothesis were false, then you test those predictions, and from the results you apply the results to the original deductive process to see if it holds up or needs revision.

All tested A is B
IF this pattern holds for all A
THEN all A is B

Form (inductive) hypothesis: all A (tentatively) is B
Test
Review

If any new A is notB then hypothesis is invalidated by deductive logic.

If all new A tested continues to be B then you cannot confirm the hypothesis by deductive logic, unless all A is tested.

Inductive logic does not do this either, though it can give you the false impression that all A is B when there is no contrary evidence.

Enjoy.


we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

This message is a reply to:
 Message 671 by Straggler, posted 11-28-2010 9:44 AM Straggler has responded

Replies to this message:
 Message 673 by Panda, posted 11-28-2010 3:54 PM RAZD has acknowledged this reply
 Message 686 by Straggler, posted 11-29-2010 1:19 PM RAZD has acknowledged this reply

  
Panda
Member (Idle past 1792 days)
Posts: 2688
From: UK
Joined: 10-04-2010


Message 673 of 744 (593681)
11-28-2010 3:54 PM
Reply to: Message 672 by RAZD
11-28-2010 1:59 PM


Re: induction vs deduction elements
Straggler writes:

Panda writes:

By definition: you cannot make general/universal rules/laws using deductive reasoning.


Do you disagree with the above?

Your answers to this question suffer from a lack of context, as you weren't involved in the original conversation.
It was used in response to the statement: "Inductive reasoning is not used in science - only deductive reasoning is used".

It would be better to ask if you agree with:
"By definition: you cannot make general/universal rules/laws in science without using inductive reasoning."

Edited by Panda, : No reason given.


This message is a reply to:
 Message 672 by RAZD, posted 11-28-2010 1:59 PM RAZD has acknowledged this reply

  
nwr
Member
Posts: 5585
From: Geneva, Illinois
Joined: 08-08-2005


Message 674 of 744 (593686)
11-28-2010 4:08 PM
Reply to: Message 650 by Modulous
11-27-2010 4:36 AM


Re: What would induction in science look like
nwr writes:
If a peer reviewed article were to publish 1000 data point, and then assert "therefore, by induction, statement x is always true", that would seem to be a clear use of induction.
Modulous writes:
If this is the only thing you consider to be induction - then we agree science doesn't generally do this.

I'm not insisting that it is the only thing. However, it is hard to think of alternatives that would count as induction.

Modulous writes:
I'm thinking science develops a theory which it doesn't say is 'true' but says is 'supported' with 'some degree of confidence' by a limited set of data points. This is what I mean by induction in science.

My view is that science develops methods that work in a particular area of study. The presented theory can be said to be the propositional face of the science. But the core of the scientific knowledge is in the methods, not in the propositions that constitute the theory. There's a lot of pragmatic support for the methods (as in "they work very well, even with intensive testing"). "Induction" is the name of a way of getting propositions from propositions. And I don't see the core of science as being a propositional investigation.


Jesus was a liberal hippie
This message is a reply to:
 Message 650 by Modulous, posted 11-27-2010 4:36 AM Modulous has responded

Replies to this message:
 Message 675 by Modulous, posted 11-28-2010 4:40 PM nwr has acknowledged this reply
 Message 676 by crashfrog, posted 11-28-2010 8:00 PM nwr has responded

  
Modulous
Member (Idle past 183 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 675 of 744 (593691)
11-28-2010 4:40 PM
Reply to: Message 674 by nwr
11-28-2010 4:08 PM


Re: What would induction in science look like
I'm not insisting that it is the only thing. However, it is hard to think of alternatives that would count as induction.

I would have thought a much more likely candidate would be found in Bayesianism somewhere, which as the article I cited earlier suggested - can be found in the sciences, even if some may reject it.

Edited by Modulous, : typo


This message is a reply to:
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