Excerpt: The educational literature on constructivism is enormous, and growing rapidly; a significant indicator is that the 1993 AERA Annual Meeting Program contained more than a score of sessions explicitly on this topic. Even as interesting a symposium as that which recently appeared in the Educational Researcher (vol. 23, 7, 1994) was able to give only an inadequate hint of the many varieties of constructivism that presently exist. It is part of my purpose in this essay to complicate matters even more by pointing to relevant discussions in other literatures that are rarely, if ever, mentioned by those embroiled in the educational debates. In particular, I will try to show that in the fields of epistemology and philosophy of science, in the relatively young discipline of science studies (an interdisciplinary philosophical, sociological, and historical field), and in the rapidly burgeoning feminist literature, there is much of relevance and interest to be found.