Telling us to obey instinct is like telling us to obey 'people.' People say different things: so do instincts. Our instincts are at war. If it is held that the instinct for preserving the species should always be obeyed at the expense of other instincts, whence do we derive this rule of precedence? To listen to that instinct speaking in its own case and deciding in its own favour would be rather simple minded. Each instinct, if you listen to it, will claim to be gratified at the expense of all the rest. By the very act of listening to one rather than to others we have already prejudged the case. If we did not bring to the examination of our instincts a knowledge of their comparative dignity we could never learn it from them. And that knowledge cannot itself be instinctive: the judge cannot be one of the parties judged: or, if he is, the decision is worthless and there is no ground for placing preservation of the species above self-preservation or sexual appetite.
C.S. Lewis, The Abolition of Man
instinct, morality, self-preservation, values