In Part Three of the Ethics, Spinoza turns to human psychology. Having investigated the nature of the mind and of its contents and established what constitutes true and adequate knowledge, he now offers an analysis of the dynamics of the ways in which the mind moves, by association and by affect, among its various states. His focus is especially on our passionate responses to the world, that is, our emotions. The discussion as it proceeds in Part Three seems perfectly descriptive, although it will certainly have implications for the way we should lead our lives (to be brought out in Parts Four and Five). Moreover, while the propositions of this part, no less than the previous elements of the work, are presented in deductive terms (and not merely as the empirical result of introspection), much of what Spinoza says about the passions seems to capture some obvious and intuitive truths about the way we think and feel about things and regard other people. Unlike the alien territory of his metaphysics, the psychological analysis of Part Three, despite its rigorous Spinozistic terminology, seems remarkably (and uncomfortably) familiar.

PSYCHOLOGIA GEOMETRICA

Spinoza opens Part Three with an indictment of the way in which philosophers – perhaps merely making explicit the naive view of ordinary people – have generally treated the mind and its relationship to the rest of the world.