It was as difficult to be independent in philosophy as it is with us to be independent in politics. When a young man joined a school, he committed himself to all its opinions, not only as to the end of life, which was the main point of division, but as to all questions on all subjects. The Stoic did not differ merely in his ethics from the Epicurean; he differed also in his theology and his physics and his metaphysics. Aristotle, as Shakespeare knew, thought young men “unfit to hear moral philosophy”. And yet it was a question—or rather the question—of moral philosophy, the answer to which decided the young man’s opinions on all other points.