In this article I reevaluate Emmanuel Kant's moral philosophy from a post-Darwinian perspective. Taking an evolutionary approach to human reasoning and incorporating some recent work on the science of the emotions, I argue that the Kantian bifurcation of reason and emotion, which underlies his moral philosophy, is no longer tenable. Kant's practical defense of his ethics as being the only option that can save morality from the dangers posed by naturalism is also considered and rejected. Instead, I argue that an evolutionary view of reason and emotion can provide an adequate ground for morality and explore the possibility and advantages of such an ethics.