Robin,
As Eliezer has pointed out, evolution is a nonhuman optimizer which is in many ways more powerful than the human mind. On the assumption that humans have a moral sense, I don’t think we should expect to be able to understand why. That might simply be a problem which is too difficult for people to solve.
That aside, a man’s virtues benefit the society he lives in; his inclination to punish sin will encourage others to act virtuously as well. If his society is a small tribe of his relatives, then even the weaker forms of kin selection theory can explain the benefit of knowledge of good and evil.
Robin, As Eliezer has pointed out, evolution is a nonhuman optimizer which is in many ways more powerful than the human mind. On the assumption that humans have a moral sense, I don’t think we should expect to be able to understand why. That might simply be a problem which is too difficult for people to solve. That aside, a man’s virtues benefit the society he lives in; his inclination to punish sin will encourage others to act virtuously as well. If his society is a small tribe of his relatives, then even the weaker forms of kin selection theory can explain the benefit of knowledge of good and evil.