The Argument from Moral Knowledge

For a while I have thought that our having knowledge of moral truths is awkward on evolutionary naturalism, and thus considered the fact that we do have knowledge of moral truths as a significant piece of evidence for traditional theism. The idea here is that, if our bodies are the result of unguided evolutionary pressures, then so are our mental faculties. Now it's not so incredibly implausible to suppose that unguided evolutionary pressures could produce in us mental faculties that were aimed at discovering truth. If our ancestors had unreliable mental faculties that produced false beliefs about the world around them, they probably wouldn't have survived long enough to reproduce. And so it's easy to imagine how survival of the fittest could translate into survival of the most knowledgeable. The problem is that there doesn't seem to be any way for natural selection to work on the our moral faculties, and so given evolutionary naturalism, it's rather awkward that we'd have properly functioning moral faculties. On the other hand, theism as is traditionally conceived expressly entails that we would have properly functioning moral faculties, and so;

K: I have moral knowledge

T: Traditional theism

N: Evolutionary naturalism

Pr(K|T) >> Pr(K|N)

Pr(T|K)Pr(K)/Pr(T) >> Pr(N|K)Pr(T)/Pr(N)

Pr(T|K) >> Pr(N|K) Pr(T)/Pr(N)

Pr(T) is roughly equal to Pr(N) and K

Therefore, Pr(T) >> Pr(N)

The naturalist could always attack the premise that Pr(T) ≈ Pr(N) with auxiliary arguments against theism, and the theist could always try to buffer the premise by providing auxiliary arguments for theism. This argument would then then be most useful in a cumulative case for theism, and against naturalism.