It is always a pity when thinkers are not equal to their own thoughts. Schopenhauer, that melancholy metaphysician, is a case in point. He extolled the Buddhistic calm of Nirvana and the supreme beatitude of living in deep thought, but he did not hesitate to beat his landlady when she committed some trivial transgression. In his attitude to events and in his relations with men, it is the business of the philosopher to display qualities flowing from the ethos of his teaching, but it is not necessarily the business of a metaphysician to do so. This is the practical and moral difference between them.
-- Notebooks Category 6: Emotions and Ethics > Chapter 1: Uplift Character > # 232