This chapter introduces some important concepts in Spinoza's philosophy that will be drawn upon extensively in subsequent chapters. In the Ethics it seems as if every concept is quite literally interconnected with every other concept, and there is no way to explain the part without reference to many other parts and the whole. Trying to understand the Ethics we are in the position of our worm in the previous chapter, trying to make sense of a whole through the parts yet at the same time recognizing that all the parts are interconnected through principles that seem out of our reach.

In order to cope with this problem, many of the best-known works on Spinoza are written as commentaries on the Ethics as a whole. By commenting on the Ethics section by section, Spinoza's terminology and concepts can be introduced in the narrative sequence in which they arise. This is, of course, very advantageous, but it makes it difficult to concentrate on a specific issue – like Spinoza's method. For this reason I pursue only two partially satisfactory alternatives. In this chapter I treat a few key concepts in order that discussion of them does not unduly detract from the larger narrative; and then, as the book proceeds, I introduce technical issues and technical problems.