 The terms of the problem as well as its solution are given by a saying to be found in the margin of the cerebral table: “Act from affection and think in order to act” (1851, v. 1, 726; E., v. 1, 594). The first part of this “systematic verse” is guaranteed by the dominance of the heart; but, among the ten “affective forces”, the first seven correspond to egoism, the final three to altruism. The whole question is knowing which ones would prevail, those of “personality” or those of “sociability”. While it is important to acknowledge the innateness of the sympathetic instincts, one is forced to admit their native weakness: the supremacy of the egoistic tendencies is so clear that it is itself one of the most striking traits in our nature. The great human problem is to reverse the natural order and to teach ourselves to live for others.