This chapter brings out in further detail the nature and interpretation of the main thesis, focusing on four key phrases in it: ‘progress’, ‘philosophy’, ‘reasonably many’, and ‘big’. It makes a brief case for the significance of the thesis. It is suggested that if there is progress in philosophy, it is epistemic progress. The chapter presents a provisional list of some of the principle topics addressed by questions of philosophy, which it is submitted from the subject matter of philosophy. The opposing claim that philosophy has no subject matter is addressed, as is the suggestion that philosophy is not individuated by its subject matter but by a distinctive epistemological approach. In particular it is suggested that this claim is implausible given the epistemological position designated in this chapter as Quinean foundationalism.