Hasdai Crescas (c. 1340-1410/11) and Simeon ben Ẓemah Duran (1361-1444) were products of the same culture and reflect a shared intellectual tradition. Persecution of the Jews of Spain in 1391 led the former to devote his life to rebuilding Spanish Jewish communities, while the latter fled Spain and became a rabbinic leader in Algiers.

As time went on, the intellectual gap between them became much wider than the sea that separated them. Duran was an eclectic thinker with a passion for the details both in his Torah study and in his analysis of the shared general knowledge of the middle ages; he combined them without hesitation in his voluminous encyclopedic writings, which reflect their common understanding in his time. Crescas was Duran’s intellectual opposite: He focused on underlying concepts and principles in a consistent way, and refrained from combining unlike things in his concise writings. He attempted to expose the conceptual basis of tradition and of philosophy, demanding that each be allowed to speak on its own terms, and eschewed the idea that each provides support for the other. He tried to think anew about common assumptions on both sides for every issue he confronted.

Crescas and Duran provide an example of how different personalities and intellectual bents can lead to vastly different outlooks, even for two people who share common intellectual roots.