The history of philosophy seems to play a very significant role in the actual practice of philosophy; historical figures come up again and again in the courses we had to take, both as undergraduates and as graduate students, and historical figures continue to come up again and again in the papers we read, the courses we teach, the conferences we attend. Philosophy seems to be a subject that is obsessed with its past, but it is more than just an obsession. Most of us would agree that understanding the history of philosophy is somehow important to doing philosophy, that we are better philosophers for knowing the history of our subject. I think that this is true. As philosophers, we have an obligation to ourselves to reflect on this fact: why is history important to our enterprise, and how is history important to our enterprise?

This is what I would like to do in this short essay, make some observations about the ways in which history of philosophy can and does influence the practice of philosophy. I shall begin by discussing the view of history found in Jonathan Bennett's recent and already enormously influential book, A Study of Spinoza's Ethics. I have chosen to talk about that book in good part because it is, I think, the best representative of a certain genre of writing in the history of philosophy; Bennett nicely articulates a view of the history of philosophy that is widespread among writers on the subject, particularly those writing in English.