Ethics and Evolution

I've been reading Street for a while, and one of her arguments I've read is incredibly strong:

In essence, it goes P1) Our ethics are incredibly strongly correlated to what is at an evolutionary advantage
P2) If there is a incredibly strong correlation between two things, then any [sound] explanation for this correlation is better than 'sheer luck'.
C1) Therefore, meta-ethicists ought to find an explanation for this 'Darwinian Dilemma' (as Street calls it in her paper)
P3) If our ethics came from evolution, we expect this correlation of our ethics to what is evolutionarily advantageous.
P4) The objectivist cannot explain effectively away the Darwinian Dilemma
C2) Therefore, objectivism in ethics, when faced with the Darwinian Dilemma, is weak while antirealism is strong.

The argument itself allows us to conclude that antirealism is much more likely than realism, by pointing to how ethics seems to be what is evolutionarily advantageous, in most circumstances. Keep in mind for many (myself included to an extent), ethics involves using rational intuitionism to work out what is right and wrong. Yet if our rational intuitionism is just evolutionary advantages, then rational intuitionist appeals to deciding what is right and wrong becomes suspect. Moreover, this is an epistemological argument. To put it another way, this is about how we gain knowledge. If our gaining of knowledge is not objective though, but instead our gaining of normative knowledge is based on what is evolutionarily advantageous, as Street argues, then objective realism becomes incredibly dubious.

* I am using these as technical terms.

SteveHawkins: Interesting.