Can evolution justify human knowledge?

While science tells us a lot about the universe in which we live, it is built on a number of assumptions. One of these is the validity of human logic. Does the human capacity for abstract thought allow us to learn the truth about the world? Since science assumes that it does, it cannot give us a non-circular answer to this question. Nevertheless it may still be worth asking what support, if any, science offers for this idea. Specifically, can the theory of evolution give us confidence in human cognitive faculties?

It has been argued by some philosophers, such as Richard Swinburne, that since natural selection acts for advantageous behaviours rather than correct logic, that there is no reason to believe that natural selection has selected for abstract thought. The usual response to this is that brains that think correctly will over the long run be advantageous and thus selectable, even though survival does not always correspond to correct logic. I’m willing to assume that’s true; to me, it seems plausible enough.

Does that mean that the knowledge problem is solved? Perhaps not. There are two reasons to doubt this. 

First: we are the only species, as far as we know, that has the capacity for abstract thought. 1 is a very small sample size on which to base conclusions. We can’t really know empirically that evolution is good at producing abstract thought without being able to study it in other animals. If there were 20 or 30 other species with this capacity, we could make that assessment, but we don’t have that luxury.

There are currently 10 million species of animals on this planet and 5 billion that have gone extinct. If I took 5 billion attempts to get my first hole in a game of golf, I wouldn’t brag about my golf game.  It looks as though evolution is terrible at producing abstract thought and we are just a freakish coincidence.

Second: Even if we assume that natural selection can and will do the job, it will still do that very slowly. So if it takes 5,000,000 years to evolve abstract thought, we might only be 25% of the way through the process. In other words, it might take 2 million more years before humans stop thinking like jellybrains and there’d be no way for us to know.

Far from providing support for the human capacity for knowledge, then, evolution widens the problem from a gap to a chasm. There is no respite from the human knowledge problem here.



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