My reply to eight good questions arising from commentary is an elaboration of my main argument that there are parallels in the epistemologies of Frege and Piaget and that these parallels have distinctive implications for developmental psychology. The eight questions are: (i) was Piaget really an epistemologist? (ii) is Piaget's epistemic subject psychological or epistemological? (iii) is Frege's non-modal logic consistent with Piaget's account of necessity? (iv) does Piaget's constructivism entail realism? (v) what is the relation between thinking and thought? (vi) is Frege's concept of mind too narrow? (vii) how are cause and reason related in the interpretation of thought? (viii) what is the status of an act of judgment in the interpretation of thought? These questions are productive: and can be developed. (C) 1999 Elsevier Science Ltd. All rights reserved.