The first Western philosophers that we know of were Ancient Greeks living on and off the coast of western Turkey in the sixth century BC. They earn the title because they tried to explain how the world worked by appeal to logos – let us translate it as ‘reason’ – and not to divine diktat. In other words, they insisted that the world be humanly intelligible and explicable without reference to the activities of supernatural beings. That did not mean they disbelieved in such beings. They just discounted them for intellectual purposes. Similarly today, a medical researcher may have strong Christian convictions but he does not invoke them in his work.