21 “... and secondary qualities, a key topic in metaphysics, epistemology, and philosophy of perception...”

22 “... of philosophy, ranging from studies primarily of interest for philosophers in logic, epistemology...”

23 “... into the traditional schemes of empiricism or idealism. Ontological and epistemological questions became once again...”

24 “... problems, of epistemology too. The interpretation of which I speak involves my taking as the centerpiece...”