Add to ORKGAbstract Quine's philosophy comprises a bewildering set of views whose integrating principle is his "confirmed extensionalism". The paper offers a historical as well as an intellectual reconstruction of extensionalism. Traditional extensionalism (Boole) freed logic from Aristotelian essentialism that had inhibited the development of logic. Quine's confirmed extensionalism is the acceptance, as a matter of course, of the validity of Frege's criticism of [Boole's] extensionalism. His confirmed extensionalism is a generalized version of the philosophy of science known as conventionalism. As such, it places the advancement of science outside the province of science proper. It is, thus, at odds with Quine's rep...