affective state participates vaguely in extension, is in fact imperfectly localized, we conclude that this state is absolutely unextended. But then the successive degrees of extension, and extensity itself, will have to be explained by I know not what acquired property of unextended states; the history of perception will become that of internal unextended states which acquire extension and project themselves without. Shall we put the argument in another form? There is hardly any perception which may not, by the increase of the action of its object upon our body, become an affection, and, more particularly, pain. Thus we pass insensibly from the contact with a pin to its prick. Inversely the decreasing pain coincides with the lessening perception of its cause, and exteriorizes itself, so to speak, into a representation. So it does seem, then, as if there were a difference of degree and not of nature between affection and perception. Now, the first is intimately bound up with my personal existence: what, indeed, would be a pain detached from the subject that feels it? It seems therefore that it must be so with the second, and that external perception is formed by projecting into space an affection which has become harmless. Realists and idealists are agreed in this method of reasoning. The latter see in the material universe nothing but a synthesis of subjective and unextended states; the former add that, behind this synthesis, there is an independent reality corresponding to it; but both con-
