The philosophical writings of Spinoza are notoriously obscure, and they have been interpreted in many ways. Some interpreters see Spinoza as (in the words of a contemporary)1 ‘the reformer of the new [sc. Cartesian] philosophy’. That is, they see him as someone who has been deeply influenced by Cartesianism, but who has introduced major changes in it, without rejecting it altogether (as, say, philosophers such as Hobbes and Gassendi did). Others, however, see Spinoza’s philosophy as deeply imbued with medieval thought, both Jewish and Christian. In the words of one prominent exponent of this view,2 ‘his mind is crammed with traditional philosophic lore and his thought turns along the beaten logical paths of mediaeval reasoning’. Such a way of thinking would be alien to that of Descartes, who (like many seventeenth-century philosophers) spurned the philosophy of the Middle Ages. There are other disagreements between Spinoza’s interpreters. For example, some see his philosophical writings as a way of expressing a kind of mystical insight, but others deny this.3 In trying to decide between these interpretations, it will be helpful to begin by giving some account of the social and intellectual milieu within which Spinoza formed his ideas.