Reddit reviews A Natural History of Human Morality

As /u/HideousRabbit notes, maybe nothing.

What does happen is that people often put forth such positions and take them to be obvious and they're not only not obvious, but they're obviously bad.

Apart from those problems, the proposal you're giving needs to be fleshed out significantly. What do you mean by "just a human construct"? What tie is that supposed to have to evolutionary theory? There's many ways you can go here. Some people want to use this line of reasoning to deny that there truly is anything such as morality, and instead we just have these things we call moral systems around but they don't have any true force. I don't have a lot of sympathy for these positions personally.

If you're interested in the relation between morality and evolutionary theory the psychologist Michael Tomasello has a new book called A Natural History of Human Morality which gives an evolutionary history of morality. It shares a number of affinities with philosophical theories of morality, including of constructivists like Stephen Darwall, Christine Korsgaard and David Gauthier.

I'm not super wide-read on the subject or anything. There do seem to be more books on this subject coming out though. E.g. Here is an interview with the author of another one:

http://www.econtalk.org/archives/2015/01/joshua_greene_o.html

Maybe that will be of some interest. Another recent book (which I read, unlike Greene's) is Michael Tomasello's Natural History of Human Morality which is about the evolution of morality (I think this is probably a key component of understanding morality). It was pretty good, although very expensive for some reason (like £25 in the UK).

Personally though I don't think anyone has cracked this nut yet.