This is an account of the world's greatest ‘intellectual virtuosos,' who are also humanity's greatest doubters and disbelievers, from the ancient Greek philosophers, Jesus, and the Eastern religions, to modern secular equivalents Marx, Freud and Darwin—and their attempts to reconcile the seeming meaninglessness of the universe with the human need for meaning,This remarkable book ranges from the early Greeks, Hebrew figures such as Job and Ecclesiastes, Eastern critical wisdom, Roman stoicism, Jesus as a man of doubt, Gnosticism and Christian mystics, medieval Islamic, Jewish and Christian skeptics, secularism, the rise of science, modern and contemporary critical thinkers such as Schopenhauer, Darwin, Marx, Freud, Nietzsche, the existentialists.