Book excerpt: The burgeoning science of ethics has produced a trend toward pessimism. Ordinary moral thought and action, we're told, are profoundly influenced by arbitrary factors and ultimately driven by unreasoned feelings. This book counters the current orthodoxy on its own terms by carefully engaging with the empirical literature. The resulting view, optimistic rationalism, shows the pervasive role played by reason our moral minds, and ultimately defuses sweeping debunking arguments in ethics. The science does suggest that moral knowledge and virtue don't come easily. However, despite the heavy influence of automatic and unconscious processes that have been shaped by evolutionary pressures, we needn't reject ordinary moral psychology as fundamentally flawed or in need of serious repair. Reason can be corrupted in ethics just as in other domains, but a special pessimism about morality in particular is unwarranted. Moral judgment and motivation are fundamentally rational enterprises not beholden to the passions.