The acquisition of knowledge is not a single unrelated occasion but rather an adaptive process in which past acquisitions modify present and future ones. In Part I of this essay in epistemology it is argued that coping with knowledge is not a passive affair but dynamic and active, involving its continuance into the stages of assimilation and deployment. In Part II a number of specific issues are raised and discussed in order to explore the dimensions and the depths of the workings of adaptive knowing. ACKNOWLEDGMENTS "Activity as A Source of Knowledge" first appeared in Tulane Studies in Philosophy, XII, 1963, "Knowing, Doing and Being" in Ratio, VI, 1964, "On Beliefs and Believing" in Tulane Studies, XV, 1966, "Absent Objects" in Tulane Studies, XVII, 1968, "The Reality Game" in Tulane Studies, XVIII, 1969, "Adaptive Responses and The Ecosys­ tem" in Tulane Studies, XVIII, 1969, "The Mind-Body Problem" in the Philosophical Journal, VII, 1970, and "The Knowledge of The Known" in the International Logic Review, I, 1970. PART I COPING WITH KNOWLEDGE CHAPTER I THE PROBLEM OF KNOWLEDGE I. THE CHOSEN APPROACH You are about to read a study of epistemology, one which has been made from a realistic standpoint. It is not the first of such interpre­ tations, and it will not be the last.