Above all else, dedicated:
Parfit had a native genius for philosophy. But he also devoted more time and concentrated effort to the development of his ideas than any other philosopher I have known. He once mentioned a passage in a book of economic history that noted that the concept of work had sometimes been understood in such a way that work was necessarily unpleasant. On this understanding, Parfit almost never worked. Yet throughout his adult life he did little other than think about, read, and write philosophy. When I visited Oxford in January and February of 2014, I stayed in his house. During those months, he left the house only a few times. In all but one instance, he left only to walk a few blocks to buy fruits and vegetables for his spartan meals. The other instance was when he walked with me to an appointment I had so that we could continue the philosophical discussion we were having. The one exception to his monomaniacal commitment to his philosophy was his architectural photography, samples of which appear on the covers of his four books. But he gave that up many years ago when he came to fear that he might not live long enough to complete his remaining work in philosophy.
There are many anecdotes about the ways in which Parfit simplified his life to take as little time as possible away from his work. He ate only twice a day, with almost no variation in what he had at each meal. He ate cold food only, mostly fruits and vegetables without any preparation. Even when he could have had freshly ground coffee with only a minute’s additional preparation, he drank instant coffee, often with water straight from the tap. He sometimes kept a book open on the chest-of-drawers so that he could read while putting on his socks. His speed in reading was phenomenal, in part because his power of concentration was prodigious. Wanting to preserve his mental and physical capacities, he took an hour every evening during his last decade to get vigorous exercise on a stationary bicycle, but never without reading philosophy (or occasionally physics) while furiously pedalling.
Parfit’s kindness and generosity, not only to his students and friends but to others as well, are legendary. The comments he gave to people on their manuscripts were sometimes longer than the manuscripts themselves, and the comments were invariably articulated in the gentlest, most tactful, encouraging, and constructive way possible. He frequently wept, not for himself but always from compassion for others.