In this chapter I discuss how Spinoza deals in the Ethics with some basic issues in the theory of knowledge, including perception and intellectual knowledge, belief, error, justification, and skepticism. I begin in Section 1 with his explanation of the nature of the mind within the context of his broader metaphysics, because this explanation is fundamental to his treatment of these epistemological topics. I then consider his theory of perception, the distinction between adequate and inadequate ideas, and his threefold classification of knowledge into imagination, reason, and intuitive knowledge. In Section 2 I take up his theory of justification and his response to skepticism; and in Section 3 I deal with his theories of belief and error. I conclude Section 3 with some observations regarding the implications of his theory of belief for his views on knowledge. / 1. Mind and cognition / The Human Mind as a Mode of the One Substance / Part 2 of the Ethics opens with a number of propositions that generally continue the account of the relation between God or substance and finite things that begins with Ip15. Thought and extension are attributes of the one substance (2p1, 2p2).