Williams was born in Westcliff-on-Sea, a suburb of Southend, Essex, to Hilda Amy Williams, née Day, a personal assistant, and Owen Pasley Denny Williams, chief maintenance surveyor for the Ministry of Works. He was educated at Chigwell School, an independent school, where he first discovered philosophy. Reading D. H. Lawrence led him to ethics and the problems of the self. In his first book, "Morality: An Introduction to Ethics" (1972), he quoted with approval Lawrence's advice to "ind your deepest impulse, and follow that."