In ethics, naturalism has been under suspicion. Factual judgments and evaluative judgments would be fundamentally different. Moral judgments are, however, based on sentiments, especially on sympathy and empathy, and therefore on our nature. Since Darwin, the general features of human inclinations, attitudes, and cognitive capacities can be viewed as the products of natural selection. Altruistic behavior in the animal world is explained through kin selection and reciprocity. Human moral behavior is biologically founded on such reciprocal altruism, which, however, tends to cause free-riders. Abilities to detect and discriminate against cheaters were developed and functioning as social selection would have established morality in humans.
