We have such a theory now; we can solve any moral problem, on any level. Self-interest, love of family, duty to country, responsibility toward the human race--we are even developing an exact ethic for extra-human relations. But all moral problems can be illustrated by one misquotation: 'Greater love hath no man than a mother cat dying to defend her kittens.' Once you understand the problem facing that cat and how she solved it, you will then be ready to examine yourself and learn how high up the moral ladder you are capable of climbing.