Plato’s ethic of world-denial is not an original creation; he takes it over in the Indian setting in which it is offered to him by Orphism and Pythagoreanism. By what route there found its way into Greek thought this pessimism which has been thought out to a system and provided with the doctrine of re-incarnation, we do not know, and shall probably never learn. The presence side by side in Greek thought of an artless optimism and a mature pessimism will always remain for us the great puzzle of Greek civilization. But if the pessimism had not been there, Plato must have introduced it. The abstract basic principle of morality which he adopts in order to preserve the absolute character of morality which he was the first to pronounce to be a necessity, precludes any other content than that of the denial of the sensible world and of natural life. Aristotle. Instruction about virtue in place of ethics Plato’s fate alarms Aristotle. He refuses to soar to the heights where Plato lost himself. How then does he fare? His object is the establishment of a serviceable ethic which is in harmony both as to extent and content with reality. What he accomplished lies before us in the [pg 043] so-called _Nicomachean Ethics_, the comprehensive work which he composed for the benefit of his son, Nicomachus. The general thought of Socrates, that ethics are a striving after happiness, he acknowledges. But at the same time he makes quite clear his opinion that the part played by activity in ethics must be a much more important one than is given to it in Plato or in the other post-Socratics. Aristotle feels that the crux of the question is the conception of activity, and this he wants to save. He therefore avoids Plato’s paths of abstract thinking, and rejects the ethic of pleasure and not-pleasure over which the Cyrenaics and Cynics work so hard. In his ethical thinking the vitality of the ancient world tries to find expression. In magnificent fashion he lays down the pre-suppositions which are necessary for the carrying through of his undertaking. He finds the motive to activity in the conception of pleasure, a thing he can do because his whole philosophy has indeed for its aim and object the conceiving of Being as formative activity. Hence the essential element in human nature also is activity. Happiness is to be defined as activity in accordance with the law of excellence. Rational pleasure is experience of the perfecting of one’s activity. Starting from the conception of pleasure which experiences itself as activity, Aristotle is on the way to comprehend ethics as deepened life-affirmation, and to attack the problem of leading the ancient world up from a naïve and unreflecting world-affirmation to a thinking one. But on the way he diverges from the high-road.