"In adolescence, I hated life and was continually on the verge of suicide, from which, however, I was restrained by the desire to know more mathematics. Now, on the contrary, I enjoy life; I might almost say that with every year that passes I enjoy it more. This is due partly to having discovered what were the things that I most desired, and having gradually acquired many of these things. Partly it is due to having successfully dismissed certain objects of desire - such as the acquisition of indubitable knowledge about something or other — as essentially unattainable. But very largely it is due to a diminishing preoccupation with myself. Like others who had a Puritan education, I had the habit of meditating on my sins, follies, and shortcomings. I seemed to myself — no doubt justly — a miserable specimen. Gradually I learned to be indifferent to myself and my deficiencies; I came to centre my attention increasingly upon external objects: the state of the world, various branches of knowledge, individuals for whom I felt affection."