In the Critique of Pure Reason, Kant attempts to formulate a distinctive refutation of an extreme Cartesian skepticism about knowledge of the existence of physical objects. According to this skeptical view, one cannot know whether there exist any physical objects, since one cannot rule out some possibilities which, if they obtained, would entail that there are no physical objects. Since one cannot know that a possibility such as that of a Cartesian evil genius does not obtain, one is not entitled to claim to know the truth of propositions about the existence of physical objects which would be false if the possibility did obtain. I Kant's general aim is to supply us with an internal refutation of such a view, i.e., one which would proceed from a premise which would itself form a part of the skeptic's position, or which he would accept. The crucial premise would be that one is the subject of self-conscious experience. An examination of the conditions for the possibility of self-conscious experience would yield the result that the existence of physical objects is such a condition. Therefore, the falsity of the skeptic's claim about lack of knowledge of the existence of physical objects would follow from his acknowledgement that he is a self-conscious experience. A weaker kind of skeptical position regarding knowledge of physical objects is suggested by Descartes' dream argument. On such a position, it would be conceded that one can know that there are physical objects, but it would be argued that one cannot know whether any of one's beliefs about the particular physical objects one seems to encounter are in fact true. This skeptical position could be supported in the following way. One cannot rule out the possibility that one's current experience is merely a dream experience. If one is dreaming, then one's current experience is not a waking experience. One cannot, then, claim to know that one is awake. From this it would appear to follow that one is not entitled to claim to know that one's current experience as of physical objects is veridical. It would appear to follow, in other