Self-realizationist theories are among the classical attempts to develop a comprehensive normative ethical theory. Plato and Aristotle, in giving classical statements of such theories, argue that a man's distinctive happiness, a man's distinctive flourishing, will only be realized when he realizes himself, i.e. when he achieves to the fullest possible degree his distinctive function. And to achieve one's function is to develop to the full those capacities which are distinctive of the human animal. In doing this we are being most truly ourselves and in doing this we are doing what it is our own nature to do. Men who cultivate to the fullest that which men and only men have will be the happiest men and in so acting they will realize themselves most fully; they will achieve their maximum potential or their fullest distinctively human growth. To so realize oneself is the final end of all moral activity. It defines what is to constitute ‘the good life’ and what is to count as ‘a good man’.