The rationalism for which Maimonides stood was, in part, a reaction to the growth of esoteric literature and its penetration of Jewish intellectual life. And rationalism did have some effect. In the twelfth and thirteenth centuries it forced the leading mystics, at any rate those with a claim to intellectual respectability, to refine their literature and corpus of belief, purge it of its magical dross and the gnostic clutter of centuries, and turn it into a coherent system.
