Baruch Spinoza (1632-1677) was very impressed with Descartes's philosophy, but he thought Descartes had made a serious mistake: It simply could not be true that mind and body are separate substances. Spinoza followed the logic to a surprising conclusion: that all things, both physical and mental, are aspects of one infinite substance. This class will explore Spinoza's reasoning and the ramifications of his understanding of reality, including its implications for religion, ethics, psychology, and environmentalism.