Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 114 (8733 total)
Current session began: 
Page Loaded: 03-26-2017 6:52 PM
466 online now:
Asgara (AdminAsgara), Astrophile, NoNukes, nwr, Phat (AdminPhat) (5 members, 461 visitors)
Chatting now:  Chat room empty
Newest Member: timtak
Post Volume:
Total: 801,991 Year: 6,597/21,208 Month: 2,358/2,634 Week: 21/525 Day: 21/11 Hour: 1/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Prev123
4
5678Next
Author Topic:   Abductive Reasoning In Science
Dr Adequate
Member
Posts: 15474
Joined: 07-20-2006
Member Rating: 3.9


Message 46 of 120 (672401)
09-07-2012 5:08 PM
Reply to: Message 45 by Blue Jay
09-07-2012 4:48 PM


Re: Abductive vs Inductive
Oh, so my misunderstanding was more with what induction is: induction is not about explaining an observation at all, but about using observations to verify a theory ...

Not quite. Induction is the leap from: "I always observe P to be true" to "P is always true."


This message is a reply to:
 Message 45 by Blue Jay, posted 09-07-2012 4:48 PM Blue Jay has acknowledged this reply

Replies to this message:
 Message 51 by RAZD, posted 09-07-2012 7:55 PM Dr Adequate has not yet responded

  
Dr Adequate
Member
Posts: 15474
Joined: 07-20-2006
Member Rating: 3.9


Message 47 of 120 (672402)
09-07-2012 5:11 PM
Reply to: Message 3 by RAZD
09-04-2012 3:26 PM


Re: hypothesis
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're wrong. It is impossible to deduce a theory from the facts (in the strict meaning of "deduce"). This applies to any theory, not just evolution.


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

  
RAZD
Member
Posts: 18241
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.0


Message 48 of 120 (672410)
09-07-2012 6:01 PM
Reply to: Message 44 by Straggler
09-07-2012 4:32 PM


redirect
deleted incomplete\duplicate post ... to redirect:

Dr Adequate: see Message 49

Enjoy

Edited by RAZD, : see next post

Edited by RAZD, : added redirect


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 44 by Straggler, posted 09-07-2012 4:32 PM Straggler has not yet responded

  
RAZD
Member
Posts: 18241
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.0


Message 49 of 120 (672414)
09-07-2012 6:34 PM
Reply to: Message 44 by Straggler
09-07-2012 4:32 PM


Re: hypothesis
Hi Straggler,

Ahhh. When in doubt pull out the Venn diagrams.....

No discussion between us is complete without it .

Yes you are wrong.

Curiously you did not show where or how. 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.

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?

Interesting that you quoted a previous post on the thread rather than the one you replied to.

You will note in the post you replied to (Message 42 - note post has been edited to add an example, as shown here) where I note that, imhysao, deductive logic can be used during the hypothesis formation process:

quote:
Logic (deductive, inductive, abductive) → hypothesis
...
You can deduce a cause → effect pattern from several observed instances,

x causes y1 (something causes a rock to fall)*
x causes y2 (something causes a pencil to fall)
x causes y3 (something causes a feather to fall)
...
x causes yn (something causes object n to fall, where n is the number of observations involved)

deduction: the pattern of cause (gravity) and effect (things falling) is the same for all n objects.

then generalize (inductive\abductive) as a general application of that cause → effect pattern:

x causes all y (something - gravity - causes all these objects to fall)


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?

Again we seem to be talking about the same thing in different ways, as this was clarified in Message 7, and I see a similar process as noted in the example re gravity.

This seems to me to be especially true for the initial formation of the theory of natural selection by Darwin, as he listed a number of situations where selection (cause) appeared to affect population traits (effect).

* I am still not entirely clear on the difference between inductive and abductive, as both are basically (informed) conjectures\guesses\opinions ...

ie -- if I (alone in the woods) think I see Sasquatch, but cannot verify it, then I am justified (informed) to hypothesize that they may exist, and (if I am interested) to proceed to predictions and testing of this conjecture\guess\opinion*

Enjoy.

ps -- *for added section* ... note I generally use word1\word2\word3 construction to imply meanings common to all words involved in an attempt to increase clarity and limit confusion.

Edited by RAZD, : clrty

Edited by RAZD, : added ending and ps


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 44 by Straggler, posted 09-07-2012 4:32 PM Straggler has responded

Replies to this message:
 Message 56 by bluegenes, posted 09-08-2012 2:00 AM RAZD has responded
 Message 68 by Straggler, posted 09-08-2012 4:53 PM RAZD has acknowledged this reply

  
RAZD
Member
Posts: 18241
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.0


Message 50 of 120 (672418)
09-07-2012 7:20 PM
Reply to: Message 43 by PaulK
09-07-2012 2:30 PM


theory acceptance and as a good working model
Hi PaulK,

So would you agree that a theory is believed on inductive or abductive grounds ?

I would say that a theory (a tested & not invalidated hypothesis) is tentatively accepted as a good\valid working model based on abductive reasoning -- it hasn't been invalidated by current testing, but still can be invalidated by new testing -- that it is a good working model to predict\apply to new situations.

deductive element:

  • the hypothesis was tested for (new) predicted situations
  • the hypothesis was not invalidated by any of the new situations
  • therefore the hypothesis is valid for the new predicted* tested situations as well as (all) old situations.

ie -- the size of (known) {A} within (possible) {B} has grown by the addition of new situations where all {A} is part of {B} is correct, and thus the hypothesis\theory that {A} ≡ {B} can still be true.

abductive element:

  • it is rational to use the theory to predict the results of new situations.

Thus we can continue to use the existence of {B} to predict - and test for - {A}.

Use of the theory to apply to new situations would be further testing of the theory to check its validity (ie everytime it is used to predict an outcome, it is being tested). See old discussions re holding a pencil over a desk and releasing it.

Enjoy.

Edited by RAZD, : clrty per comments from PaulK re predictions (see strike out at *


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 43 by PaulK, posted 09-07-2012 2:30 PM PaulK has responded

Replies to this message:
 Message 57 by PaulK, posted 09-08-2012 2:56 AM RAZD has responded

  
RAZD
Member
Posts: 18241
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.0


Message 51 of 120 (672421)
09-07-2012 7:55 PM
Reply to: Message 46 by Dr Adequate
09-07-2012 5:08 PM


Abductive vs Inductive vs Deductive
Hi Dr Adequate

... "I always observe P to be true" ...

Would that not be deductive logic?

  • 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).

You can also say that it is a fact that (so far) I have always observed P to be true, while you cannot say this if it is inductive logic, yes?

Enjoy.

notes:

  • 'true' and 'fact' are not used as absolutes but close approximations, as previously discussed on the thread about "KNOWING" vs "knowing" (I forget which one it was, but I believe Straggler started it). Science approximates reality by testing and throwing out what does not appear to be "TRUE" so the approximations of 'truth', 'fact' and 'knowledge' become closer to "TRUTH", "FACT" and "KNOWLEDGE" as time passes, where
  • the use of 'truth', 'Truth' and 'TRUTH' etc is taken from jar's distinctions of tentativity to absolute versions of the words, and
  • it is possible to 'know' 'truth' and 'fact' ... it may be possible to 'Know' 'Truth' and 'Fact' (very close approximations, laws), but it is highly problematic that we could 'KNOW' 'TRUTH' and 'FACT' (ie we would need to be omniscient to reach these absolute levels)

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 46 by Dr Adequate, posted 09-07-2012 5:08 PM Dr Adequate has not yet responded

Replies to this message:
 Message 52 by nwr, posted 09-07-2012 8:09 PM RAZD has responded
 Message 55 by Blue Jay, posted 09-07-2012 10:40 PM RAZD has responded

  
nwr
Member
Posts: 5504
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.9


Message 52 of 120 (672422)
09-07-2012 8:09 PM
Reply to: Message 51 by RAZD
09-07-2012 7:55 PM


Re: Abductive vs Inductive vs Deductive
Abductive vs Inductive vs Deductive

Why suppose that those are the only ways of reasoning? Perhaps that's a false trichotomy.

(firefox spell checker does not like "trichotomy" -- hmm, it doesn't like "firefox" either).


Jesus was a liberal hippie

This message is a reply to:
 Message 51 by RAZD, posted 09-07-2012 7:55 PM RAZD has responded

Replies to this message:
 Message 53 by RAZD, posted 09-07-2012 8:35 PM nwr has responded

  
RAZD
Member
Posts: 18241
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.0


Message 53 of 120 (672423)
09-07-2012 8:35 PM
Reply to: Message 52 by nwr
09-07-2012 8:09 PM


Re: Abductive vs Inductive vs Deductive
Hi nwr,

Why suppose that those are the only ways of reasoning? Perhaps that's a false trichotomy.

Perhaps ... can you suggest some other means of reasoning?

(firefox spell checker does not like "trichotomy" -- hmm, it doesn't like "firefox" either).

Firefox spell checker does not like a lot of words, especially science terms and little used terms (consilience for example). It will also not like other forms of words added to the dictionary (different endings such as -ive and -ion). It would be interesting to have a compiled spell check dictionary from many sources similar to wikipedia ...

Enjoy

Edited by RAZD, : slepling


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 52 by nwr, posted 09-07-2012 8:09 PM nwr has responded

Replies to this message:
 Message 54 by nwr, posted 09-07-2012 9:34 PM RAZD has responded

  
nwr
Member
Posts: 5504
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.9


(1)
Message 54 of 120 (672425)
09-07-2012 9:34 PM
Reply to: Message 53 by RAZD
09-07-2012 8:35 PM


Re: Abductive vs Inductive vs Deductive
nwr writes:
Why suppose that those are the only ways of reasoning? Perhaps that's a false trichotomy.
RAZD writes:
Perhaps ... can you suggest some other means of reasoning?

I don't know if there is a name for what is missing. Philosophers don't seem to recognize it, which is why they always fall back on induction and abduction.

I tend to call it "geometric reasoning".

In mathematics, deductive reasoning begins after you have axioms. But, arguably, the most important part of mathematics is coming up with axioms in the first place. And that's what I am calling "geometric reasoning", in part because classical geometry is a good example of this.


Jesus was a liberal hippie

This message is a reply to:
 Message 53 by RAZD, posted 09-07-2012 8:35 PM RAZD has responded

Replies to this message:
 Message 58 by RAZD, posted 09-08-2012 11:06 AM nwr has responded

  
Blue Jay
Member (Idle past 49 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


(1)
Message 55 of 120 (672428)
09-07-2012 10:40 PM
Reply to: Message 51 by RAZD
09-07-2012 7:55 PM


Re: Abductive vs Inductive vs Deductive
Hi, RAZD.

RAZD writes:

... "I always observe P to be true" ...

Would that not be deductive logic?

  • 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).

But, you stopped a step early: the inductive step is to then conclude that P is always true, even in cases where you haven't yet made any observations. Of course, inductive conclusions step beyond the empirical evidence, so they are always treated as tentative. That's the whole reason for the principle of tentativity.

-----

AbE: Also, I note that Firefox still doesn't like "consilience," even if you spell it right.

Edited by Blue Jay, : marked addition


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


This message is a reply to:
 Message 51 by RAZD, posted 09-07-2012 7:55 PM RAZD has responded

Replies to this message:
 Message 60 by RAZD, posted 09-08-2012 11:59 AM Blue Jay has not yet responded

  
bluegenes
Member
Posts: 2967
From: U.K.
Joined: 01-24-2007


Message 56 of 120 (672433)
09-08-2012 2:00 AM
Reply to: Message 49 by RAZD
09-07-2012 6:34 PM


Re: hypothesis
RAZD writes:

This seems to me to be especially true for the initial formation of the theory of natural selection by Darwin, as he listed a number of situations where selection (cause) appeared to affect population traits (effect).

That's observation. From those observations in particular species, he could make the inductive hypothesis that natural selection effected all organisms around the world in both present and past. This is inductive reasoning from Darwin's particular examples to the general, and cannot be proven by deductive logic.

Then, he could make an explanatory abductive hypothesis: that natural selection is the cause or driving force behind the "origin of species".

Deductive reasoning comes in at this point, and is very important. It is how we decide what would necessarily follow from the hypotheses that have been made. That's how we establish what their predictions are.

Science necessarily uses a lot of induction and abduction. That's why it's a mistake to criticise scientific laws and theories on the grounds that they are deductively fallacious. It can, however, be right to criticise a claimed prediction on the grounds that it is not deductively valid.

P1 Darwin's theory (of transition) is correct.
P2 Organisms fossilize
C: There will be "transitional" fossils.

If we're predicting transitional fossils from Darwin's theory, then that syllogism should be valid, but not, of course, necessarily sound, because we're using the inductive/abductive theory we're testing as one of the premises.

If suggested as a prediction, transitional fossils should be deductively necessary to the theory, not just compatible with it.


This message is a reply to:
 Message 49 by RAZD, posted 09-07-2012 6:34 PM RAZD has responded

Replies to this message:
 Message 63 by RAZD, posted 09-08-2012 1:11 PM bluegenes has responded

  
PaulK
Member
Posts: 12442
Joined: 01-10-2003
Member Rating: 2.5


Message 57 of 120 (672435)
09-08-2012 2:56 AM
Reply to: Message 50 by RAZD
09-07-2012 7:20 PM


Re: theory acceptance and as a good working model
Firstky, let us be clear that a theory is not something that can be falsified as easily as a hypothesis. What you have described works well for testing a hypothesis but would generally cause a theory to be revised rather than discarded.

quote:

I would say that a theory (a tested & not invalidated hypothesis) is tentatively accepted as a good\valid working model based on abductive reasoning -- it hasn't been invalidated by current testing, but still can be invalidated by new testing -- that it is a good working model to predict\apply to new situations.

deductive element:

  • the hypothesis was tested for (new) predicted situations
  • the hypothesis was not invalidated by any of the new situations
  • therefore the hypothesis is valid for the new predicted situations as well as (all) old situations


Here, you have run headfirst into the problem of induction. Testing a hypothesis under new conditions is certainly useful but not for your "deduction" (which is not valid). Indeed it would seem to be an abduction i.e. success in the test is better explained by the hypothesis applying, rather than chance, or some more convoluted explanation.

In fact you seem to be assuming that the problem of induction is simply our practical inability to test all possible conditions. This is not so. We cannot deductively determine that our hypothesis works under any particular set of conditions merely by testing it. Falsification is deductive, confirmation under such tests is always inductive.

quote:

abductive element:
  • it is rational to use the theory to predict the results of new situations.


Presumably given the results of testing under a sufficiently large number of variations -including all suspected of being relevant.

But for theories there is more than this. The theory of evolution offered a framework to understand the hierarchy of taxonomic classification, biogeographic distribution and the fossil record. This presented a strong abductive ground to accept the theory on the grounds of explanatory power.


This message is a reply to:
 Message 50 by RAZD, posted 09-07-2012 7:20 PM RAZD has responded

Replies to this message:
 Message 61 by RAZD, posted 09-08-2012 12:18 PM PaulK has responded

    
RAZD
Member
Posts: 18241
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.0


Message 58 of 120 (672448)
09-08-2012 11:06 AM
Reply to: Message 54 by nwr
09-07-2012 9:34 PM


Before Abductive, Inductive, or Deductive reasoning ...
Hi nwr,

In mathematics, deductive reasoning begins after you have axioms. But, arguably, the most important part of mathematics is coming up with axioms in the first place. And that's what I am calling "geometric reasoning", in part because classical geometry is a good example of this.

So we are talking about the generation of the basic axioms \ first principles \ a priori assumptions?

Examples pertinent to this forum would be:

  1. GDI: god did it (ie - ultimately meaning everything you see is illusion\deception)
  2. WYSIWYG: what you see is what you get (ie - evidence doesn't mislead\lie)
  3. COMBO: a combination of 1 and 2 (ie - evidence shows how god did it)

creationists\fundamentalists\IDologists* tend to 1
atheists tend to 2
deists\theists tend to 3
agnostics between 2 and 3

... and then see how consistent the results are?

Enjoy

* in my book IDologists are similar to deists, except they put theology first and evidence second, while deists put evidence before theology (treating theology as an hypothesis rather than fact).


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 54 by nwr, posted 09-07-2012 9:34 PM nwr has responded

Replies to this message:
 Message 59 by nwr, posted 09-08-2012 11:29 AM RAZD has responded
 Message 82 by RAZD, posted 09-09-2012 7:44 PM RAZD has acknowledged this reply

  
nwr
Member
Posts: 5504
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.9


Message 59 of 120 (672449)
09-08-2012 11:29 AM
Reply to: Message 58 by RAZD
09-08-2012 11:06 AM


Re: Before Abductive, Inductive, or Deductive reasoning ...
RAZD writes:
  1. GDI: god did it (ie - ultimately meaning everything you see is illusion\deception)
  2. WYSIWYG: what you see is what you get (ie - evidence doesn't mislead\lie)
  3. COMBO: a combination of 1 and 2 (ie - evidence shows how god did it)

No, no, and no (in that order).

Jesus was a liberal hippie

This message is a reply to:
 Message 58 by RAZD, posted 09-08-2012 11:06 AM RAZD has responded

Replies to this message:
 Message 64 by RAZD, posted 09-08-2012 1:14 PM nwr has responded

  
RAZD
Member
Posts: 18241
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.0


Message 60 of 120 (672451)
09-08-2012 11:59 AM
Reply to: Message 55 by Blue Jay
09-07-2012 10:40 PM


steps from initial hypothesis to accepted theory
Hi Blue Jay

But, you stopped a step early: the inductive step is to then conclude that P is always true, even in cases where you haven't yet made any observations. ...

Not really, imho, the inductive step would follow the deductive analysis of the new information to see how it conforms to the hypothesis:

p1: the hypothesis has been tested and new observations made
p2: for all observations made so far (old and new) P is true (deductive analysis)
c: it is possible that P is true for all cases

p1 is establishing the new objective evidence data from testing
p2 is the objective deductive analysis of the new data results compared to the hypothesis
c is the tentative inductive conclusion, the proposed theory

... Of course, inductive conclusions step beyond the empirical evidence, so they are always treated as tentative. That's the whole reason for the principle of tentativity.

As I see it the inductive conclusion must follow deductive analysis of the testing to conclude that the new evidence either invalidates or does not invalidate the hypothesis:

If P(new data) is true, then the hypothesis is not invalidated
If P(new data) is not true, then the hypothesis is invalidated

If the new evidence invalidates the hypothesis there is no (valid\rational) theory at this point, and you must start over.

If this is the first testing of the hypothesis (by the author proposing it) then it is a step closer to being considered a valid accepted theory (there still remains independent confirmation \ peer review before it is accepted as a valid theory).

That's my take on it, based on everything I've seen so far, regarding the scientific process of getting from untested hypothesis to tentatively proposed (ie - marginally tested by author hypothesis) theory to accepted theory.

Further independent testing can lead to a theory being regarded as a "strong" theory (ie - evolution and gravity), but this is still just a greater degree of acceptance, based on the amount of evidence supporting the theory, it still is tentative.

An example of this process would be cold fusion, where the authors published their proposed theory and their testing data, but independent replication\substantiation could not be made (independent results did not conform to the hypothesis), and the proposed theory went into the dustbin.

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 55 by Blue Jay, posted 09-07-2012 10:40 PM Blue Jay has not yet responded

  
Prev123
4
5678Next
Newer Topic | Older Topic
Jump to:


Copyright 2001-2015 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2017