Extensionalism as Exorcism

This discussion is devoted to explaining the revolutionary character of extensionalism. We are thus slowly zeroing in on Boole: you should soon feel the domino effect that he impelled, the rapid unstoppable toppling of one traditional dogma after another. Our aim is to emphasize the radical alternative to Aristotelian essentialism that Boole’s extensionalism comprises; that it thus exorcises Aristotle’s essences, thereby setting logic free of its ancient, traditional constraints. Let me first offer in this chapter a description of extensionalism in the abstract. Then, in the following chapters, I will enrich that description with a discussion of a few decisive moments in that historical development. Revolutionary ideas rarely mature at the moment of their inception. Extensionalism is no exception, though it did mature at an astonishingly high rate. Since things will happen fast once they are set into motion it helps to take a good look at the fully fledged idea before surveying its chronicles so as to find its earliest sources and announce its precise moment of inception.