is remembered in philosophy principally for a simple version of the cyclical view of history (see eternal return). He believed that in a period of about 120 years a people would pass through the cycle of primitivism, nomadic life, and civilization, the last of which would fall as a new cycle commenced. He is regarded as the first (and still the greatest) historian of Arabic logic, possibly the most outstanding figure in the social sciences between Aristotle and Machiavelli.