One set of views that I have often raised objections to is the idea that morality is an evolved disposition. Yet, I find this view repeated yet again, this time at Letters from Le Vrai.
Let me first say there have been an increasing number of plausible, evidence-based and well-reasoned accounts of the evolution of morality in the human animal, even tracing its roots to our primate cousins.
Nope, not plausible. They all contain a fundamental logical error - confusing the concepts of 'is desired' (a description) and 'should be desired' (a prescription). It is quite possible to show that, through evolution, humans do desire sex. It is quite impossible to expect a study of biology to prove that humans should value sex.
The most important objection - if humans have so much innate morality evolved into us, then why is it that we do so much evil? Indeed, how does evil happen at all? I mean, everything we do is based on our biology, so how do we tell the difference between 'good' biology and 'bad' biology?
However, the greatest irony is that this article expresses the Euthyphro problem with respect to the idea that morality comes from God. Yet, it ignores the fact that the idea that morality comes from our genes has exactly the same problem.
"Is X good because it is loved by our genes? Or is X loved by our genes because it is good?" If we say that it is the former, then the most horrendous things can be moral, if we evolve a disposition to like it. And, remember, nature invented the predator and the parasite. If we say the latter, then 'good' is still a concept that is quite independent of our evolved dispositions, and a study of our evolved dispositions is quite distinct from a study of what is good.
Like I said, I have covered this topic quite a bit. If you're interested, you can find more detailed arguments in:
Richard Dawkins; Morality and the Selfish Gene
Evaluating Moral Theories
The Genetic Morality Delusion