the Urban Revolution of the Bronze Age, that affected the Near East, India and China well before Europe and that was much advanced by the adoption of writing. Under these conditions we find a long-term exchange of information between East and West, and the dominance of one followed by the dominance of the other - in other words, alternation rather than dominance. There were measures during the Renaissance in Europe that made for continuous growth, especially the secularization of learning, but it appears that the period of Western supremacy is now coming to an end and that we are about to experience a further alternation in favour of the East.