Modern epistemology rests on a number of assumptions about ideas, the mind, and the brain. The notions that ideas are in the mind, that the mind is in the brain, and that ideas are somehow caused by whatever causes brain activity, gave birth to both modern psychology and epistemology in the seventeenth century. The successes of this science spurred epistemologists more and more to accept these assumptions. Thus, by the end of the eighteenth century even philosophers who vehemently disbelieved that scientific explanations of mental phenomena could be produced nevertheless went along with the above assumptions.¹ From that time forward epistemologists have rarely debated these fundamental premises, taking them as givens.² Yet I contend that we had better begin to query these assumptions, because they have not led to a satisfactory science of cognition. On the contrary, the puzzles concerning human knowledge of the external world have deepened, not lessened, as an experimental psychology based on the above assumptions has evolved. The purpose of this paper is two-fold. First, to give sufficient historical and critical background for readers to appreciate the many scientific anomalies spawned by the hypothesis that ideas are in the mind which is in the brain.