I doubt that this gentleman and I see eye-to-eye on everything, but I also believe in the power of evolutionary theory to explain many human behaviors:
Behavioral economists are inspired by psychology, not by evolutionary theory, and not even psychology writ large, but a particular sub-discipline called cognitive heuristics and biases, which shows how often people depart from the expectations of rational choice theory. The result is a long list of “anomalies” and “paradoxes” but no positive account of our psychological mechanisms as a product of genetic and cultural evolution. I wish that I could report otherwise, but it is necessary to take the Evolution Challenge for the field of behavioral economics, no less than for neoclassical economics....Philosophy as a discipline also needs to do more to account for the lessons of evolutionary science. Modern philosophy is dominated by the influence of Kant and Hegel, for whom the rational nature of humankind was the really important thing. In this they felt believed they were drawing upon and improving the legacy of the ancients, who had argued that thought was the faculty by which we regulate all our other faculties (Plato), or even that thinking was the essential nature of humanity (Aristotle).
What goes for economics also goes for every other body of knowledge about our species.
The accounts of human nature arising from this rationality-centered picture tend to be wrong exactly where evolutionary theory says they should be wrong. It also tends to lead to a misreading of the ancients, who were closer to questions of survival, life, and death -- and therefore to evolution as a process. If you read Plato's Republic as a defense of reason, for example, you're missing the fear of destruction that arose from the Spartan conquest of Athens, the civil war, the tyranny. For that matter, if you read Aristotle as endorsing rationality as the dominant fact of human life, you've misunderstood what he meant by "reason." Reason, for the ancients, is a faculty that is supposed to be able to aim at both truth and beauty.
I doubt you can get to truth with reason alone; but I'm sure you can't get to beauty! Even the most friendly reading -- beauty as some sort of compliance to rules of symmetry or mathematical formulae -- still doesn't really get you there. Nor does it explain virtues like courage, magnanimity, friendship, or love.
Letting humans be a kind of evolved animal as well as a thinking being allows their animal nature to be as important in your philosophy as it proves to be in reality. The question becomes not: can reason control animality? Rather, the question is: what is the right balance between reason and animality for the best kind of life?