98. It was a matter of course that the vulnerable passages of the six Meditations would not escape the spear of so skilful an antagonist as Gassendi. But many of his objections appear to be little more than cavils; and upon the whole, Descartes leaves me with the impression of his great superiority in metaphysical acuteness. It was indeed impossible that men should agree, who persisted in using a different definition of the important word, _idea_; and the same source of interminable controversy has flowed ever since for their disciples. Gassendi adopting the scholastic maxim, “Nothing is in the understanding, which has not been in the sense,” carried it so much farther than those from whom it came that he denied anything to be an idea but what was imagined by the mind. Descartes repeatedly desired both him and Hobbes, whose philosophy was built on the same notion, to remark that he meant by idea, whatever can be conceived by the understanding, though not capable of being represented by the imagination.[241] Thus we imagine a triangle, but we can only conceive a figure of a thousand sides; we know its existence, and can reason about its properties, but we have no image whatever in the mind, by which we can distinguish such a polygon from one of a smaller or greater number of sides. Hobbes, in answer to this, threw out a paradox which he has not, at least in so unlimited a manner, repeated, that by reason, that is, by the process of reasoning, we can infer nothing as to the nature of things, but only as to their names.[242] It is singular that a man conversant at least with the elements of geometry should have fallen into this error. For it does not appear that he meant to speak only of natural substances, as to which his language might seem to be a bad expression of what was afterwards clearly shown by Locke. That the understanding can conceive and reason upon that which the imagination cannot delineate, is evident not only from Descartes’ instance of a polygon, but more strikingly by the whole theory of infinites, which are certainly somewhat more than bare words, whatever assistance words may give us in explaining them to others or to ourselves.[243]