Even though the question of the highest good and what it consists in lay at the basis of the Ancients ' moral systems, it seems to have gone out of fashion in the Modern era. However, according to Kant, man cannot will anything but under the idea of good and, in order to be able to bring the series of his ends to a close, he needs to conceive the idea of an unconditioned end of his, the "highest good". By tackling the problem of the universal meaning of human life, Kant pays tribute to an ancient approach to practical philosophy in which the latter, in its teleological aspect, teaches man what the absolutely necessary end of his conduct must consist in and how he can attain it. As a result, he builds a doctrine of the summum bonum, following in the Ancients' footsteps, the conclusion of which doctrine lies in the answer to philosophy's two pratical questions. What may I hope (the question concerning the essence of the highest good)? What am I to do (the question concerning the conduct resulting in the highest good)? But the Copernican Revolution in ethics is the discovery that the concept of the good and that of the highest good are determined by the moral law. Kantian ethics formulates the moral law first, and defines the good and the highest good later, in the converse order from that in which the Ancients operated. This original method is responsible for a theory that opposes ancient ethics in many ways. It leads Kant to the idea that human ends are heterogeneous and that the highest good is a synthesis based on a relation of subordination, i.e., happiness conditioned by morality.