[AQ] This confusion between conceiving a concrete thing and knowing the meaning of abstract terms is as old as Toland's _Christianity not Mysterious_, and, indeed, has its germ, though not its development, in the teaching of his assumed master, Locke. Locke taught that all our knowledge is founded on simple ideas, and that a complex idea is merely an accumulation of simple ones. Hence Toland maintained that no object could be mysterious or inconceivable if the terms in which its several attributes are expressed have ideas corresponding to them. But, in point of fact, no simple idea can be conceived as an object by itself, though the word by which it is signified has a perfectly intelligible meaning. I cannot, _e.g._, conceive whiteness by itself, though I can conceive a white wall, _i.e._, whiteness in combination with other attributes in a concrete object. To conceive attributes as coexisting, however, we must conceive them as coexisting in a certain manner; for an object of conception is not a mere heap of ideas, but an organized whole, whose constituent ideas exist in a particular combination with and relation to each other. To conceive, therefore, we must not only be able to apprehend each idea separately in the abstract, but also the manner in which they may possibly exist in combination with each other. "Something infinite," says Mr. Mill, "is a conception which, like most of our complex ideas, contains a negative element, but which contains positive elements also. Infinite space, for instance; is there nothing positive in that? The negative part of this conception is the absence of bounds. The positive are, the idea of space, and of space greater than any finite space."--(P. 45.)