 The "God is Dead" movement in the 1960s, and especially its reflections on theological implications of the atrocities of the Nazi regime and the carnage of World War II, had an important influence on his abandonment of traditional theism.Finally, teaching courses on the philosophy of religion and on various philosophical systems in a secular university challenged him constantly to reflect on the relevance of religious and philosophical thought for his time and to continue to work out his own religious and philosophical outlook.He has been strongly influenced by the thought of William James, John Dewey, Alfred North Whitehead, and Paul Tillich in doing so, but other great philosophical and religious thinkers of the Western tradition have made their decisive contributions to his outlook as well, as have important writers about Eastern ways of thinking and living.