To myself it seems that the most important political result of the vast range of new knowledge started by Darwin’s work may prove to be the extension of the idea of conduct so as to include the control of mental processes of which at present most men are either unconscious or unobservant.  The limits of our conscious conduct are fixed by the limits of our self-knowledge.  Before men knew anger as something separable from the self that knew it, and before they had made that knowledge current by the invention of a name, the control of anger was not a question of conduct.  Anger was a part of the angry man himself, and could only be checked by the invasion of some other passion, love, for instance, or fear, which was equally, while it lasted, a part of self.  The man survived to continue his race if anger or fear or love came upon him at the right time, and with the right intensity.  But when man had named his anger, and could stand outside it in thought, anger came within the region of conduct, Henceforth, in that respect, man could choose either the old way of half-conscious obedience to an impulse which on the whole had proved useful in his past evolution, or the new way of fully conscious control directed by a calculation of results.

A man who has become conscious of the nature of fear, and has acquired the power of controlling it, if he sees a boulder bounding towards him down a torrent bed, may either obey the immediate impulse to leap to one side, or may substitute conduct for instinct, and stand where he is because he has calculated that at the next bound the course of the boulder will be deflected.  If he decides to stand he may be wrong.  It may prove by the event that the immediate impulse of fear was, owing to the imperfection of his powers of conscious inference, a safer guide than the process of calculation.  But because he has the choice, even the decision to follow impulse is a question of conduct.  Burke was sincerely convinced that men’s power of political reasoning was so utterly inadequate to their task, that all his life long he urged the English nation to follow prescription, to obey, that is to say, on principle their habitual political impulses.  But the deliberate following of prescription which Burke advocated was something different, because it was the result of choice, from the uncalculated loyalty of the past.  Those who have eaten of the tree of knowledge cannot forget.

In other matters than politics the influence of the fruit of that tree is now spreading further over our lives.  Whether we will or not, the old unthinking obedience to appetite in eating is more and more affected by our knowledge, imperfect though that be, of the physiological results of the quantity and kind of our food.  Mr. Chesterton cries out, like the Cyclops in the play, against those who complicate the life of man, and tells us to eat ‘caviare on impulse,’ instead of ’grape nuts on principle.’[59] But since we cannot unlearn our knowledge, Mr. Chesterton