|
Register | Sign In |
|
QuickSearch
Thread ▼ Details |
Member (Idle past 93 days) Posts: 10333 From: London England Joined: |
|
Thread Info
|
|
|
Author | Topic: Abductive Reasoning In Science | |||||||||||||||||||||||||||||||||||||||
Dr Adequate Member (Idle past 312 days) Posts: 16113 Joined: |
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."
|
|||||||||||||||||||||||||||||||||||||||
Dr Adequate Member (Idle past 312 days) Posts: 16113 Joined: |
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.
|
|||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
deleted incomplete\duplicate post ... to redirect:
Dr Adequate: see Message 49 Enjoy Edited by RAZD, : see next post Edited by RAZD, : added redirectby 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)
|
|||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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: 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 psby 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)
|
|||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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:
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:
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 *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)
|
|||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi Dr Adequate
... "I always observe P to be true" ... Would that not be deductive logic?
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:
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)
|
|||||||||||||||||||||||||||||||||||||||
nwr Member Posts: 6412 From: Geneva, Illinois Joined: Member Rating: 4.5 |
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
|
|||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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, : sleplingby 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)
|
|||||||||||||||||||||||||||||||||||||||
nwr Member Posts: 6412 From: Geneva, Illinois Joined: Member Rating: 4.5
|
nwr writes: Why suppose that those are the only ways of reasoning? Perhaps that's a false trichotomy. RAZD writes:
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.Perhaps ... can you suggest some other means of reasoning? 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
|
|||||||||||||||||||||||||||||||||||||||
Blue Jay Member (Idle past 2726 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined:
|
Hi, RAZD.
RAZD writes: ... "I always observe P to be true" ... Would that not be deductive logic?
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.
|
|||||||||||||||||||||||||||||||||||||||
bluegenes Member (Idle past 2505 days) Posts: 3119 From: U.K. Joined: |
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.
|
|||||||||||||||||||||||||||||||||||||||
PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
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: 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: 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.
|
|||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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:
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).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)
|
|||||||||||||||||||||||||||||||||||||||
nwr Member Posts: 6412 From: Geneva, Illinois Joined: Member Rating: 4.5 |
RAZD writes:
No, no, and no (in that order).
Jesus was a liberal hippie
|
|||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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 testingp2 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.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)
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024