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If our knowledge of deductive principles is a result of evolution... doesn't this mean that we arrive at deductive principles inductively?

Assuming deductive principles are beneficial for survival, evolution selected for them...

If so, then the reason we have deductive principles, is because they work... since they worked, the principles survived. Isn't this induction at work? Ultimately the reason we perform deduction is because it has worked in the past...

But if this is the case, doesn't that mean that justification of deduction is just as problematic, if not more problematic than justification of induction? Not only that... but induction is in some sense prior to deduction...

Is there literature on this topic... specifically the role of evolution in induction and deduction.

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    we studied the psychology of deduction (e.g. why it is that so many people can't do it) in psych class, there's a substantial literature to it. if not for google, i would find the notes i made. can't remember any work on evolutionary aspects, however. i like the question, and may do some light googling to add an answer or further comment. what impressed me about 'deduction', when i enocuntered it (and i really believe everyone should be taught it at school) is just that it always works – user25714 Jul 26 '17 at 9:43
  • on the question of justification, i think you're confusing genealogy with justification, but i'm not really sure – user25714 Jul 26 '17 at 9:47
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    Trial and error is not an inductive process, at least not in the sense that it puts many examples together to constitute a solution. Failing is deductive and trying can be random -- look at how a dog learns to open a door -- there is no induction going on. I might start from Dennet's "Consciousness Explained", which collects a lot of references to ideas about the evolution of thinking processes, because he does good footnotes that would help you find the literature linked to his topics. – jobermark Jul 26 '17 at 17:51
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    Logic-from-evolution was Mill's theory, see psychologism. As anti-psychologists (Frege, Husserl) pointed out it is self-refuting, among other problems, since one needs logic to deduce the very psychologistic conclusions. Psychologism was largely abandoned after WWI. A distant echo is Quine's contention that logic and mathematics face the same "tribunal of experience" as the rest of science, but Quine of course rejects the foundationalist idea of justifying any piece of the "web of belief" (such as logic or deduction) in isolation altogether. – Conifold Jul 26 '17 at 19:36
  • @Conifold, I agree that it's self refuting. Meaning doubting logic leads to skepticism regarding all knowledge. But there's still the experimental/factual question as to how we come to know these principles... or whether evolutionary systems (like neural networks) can arrive at these principles without being pre-programmed with them... just by mutation and natural selection. – Ameet Sharma Jul 27 '17 at 11:12
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A related question would be "have we arrived at deductive principles?" If we were to start in the context which assumes humans evolved (and we'll hand-wave assume we both agree on what "evolved" means), can we justify the claim that we have arrived at deductive or inductive principles?

Both deduction and induction operate on absolute truth. Evolution is not actually inductive in that it never fully assumes that "because A worked in the past, A will always work." It never reaches that level of certainty. It's always trying new things.

Indeed even the concept of "knowledge," as typically defined in philosophy, is tricky with a fallible evolved brain. All sorts of philosophical terms require special treatment if we get rid of the foundations those terms are built on. Instead we might have to talk about the terms as "ideals," which cannot be achieved by an evolved brain but which may have meaning in some "perfect" sense.

It's not that it can't be done. It just requires a bit more care to avoid these sorts of paradoxical results that arise from assuming we have achieved certain ideals, such as those of truth.

  • But can we deny deduction? It's self-refuting to do so isn't it... so on some level I am forced to accept that it is absolute truth, and can't deny it. But if evolution can never lead to this kind of absolute truth, does that mean my knowledge of induction is not due to evolution? – Ameet Sharma Jul 27 '17 at 19:28
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    Well, you are free to feel compelled to accept it. There's plenty of philosophies which would challenge your certainty in it (which is slightly different from denying it). It would be reasonable to state that if you have knowledge of induction, in the strictest sense, then it is not due to evolution. Then you begin the search for something metaphysical to explain this knowledge which is not the product of evolution. That being said, I find the more interesting line of reasoning starts with questioning what we really know in the first place. – Cort Ammon Jul 27 '17 at 20:31
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Let's take a quick look at deductive reasoning and inductive reasoning.


Deductive: "All men are mortal. John is a man. Therefore, John is mortal."

True statement ---> True statement ---> True statement

Notice what happens when we introduce a falsehood

"All women are immortal. Jane is a woman. Therefore, Jane is immortal."

False statement ---> True statement ---> False statement


Inductive: "I pull a penny from a coin bag. I pull another penny. Therefore, all coins in the bag are pennies."

True statement ---> True statement ---> Potentially False statement


Both inductive and deductive reasoning are processes, with advantages and disadvantages. Our "knowledge" of these processes and our ability to use them is really a matter of intelligence. For example, by knowing that inductive reasoning will ALWAYS produce a potentially false statement, we can set up systems to adapt when the process gave us a bad result.

Alternatively, by lacking intelligence, we might setup a system (e.g., a government), that operates on the process of inductive reasoning as though it only produced good results. The citizens of that society would be less likely to succeed and less likely to populate the planet.

There is a multitude of research on the correlations of evolution and intelligence. Here is an article to get you started: https://faculty.franklin.uga.edu/rkthomas/sites/faculty.franklin.uga.edu.rkthomas/files/Thomas1980BBE_3.pdf

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