Page:A Philosophical Inquiry Concerning Human Liberty (3rd ed., 1735).djvu/16

 and determinate in us, as the Idea of a triangle or a square is, when we discourse of either of them; otherwise, the term is an empty sound. What hinders us then from putting the Idea signify’d by the term into a Proposition, any more than the Idea of a triangle or a square? And why cannot we compare that Idea with another Idea, as well as any two other ideas together: since comparison of Ideas consists in observing wherein Ideas differ, and wherein they agree: to which nothing is requisite in any Ideas, but their being distinct and determinate in our Minds? And since we ought to have a distinct and determinate Idea to the term, whenever we use it, and as distinct and determinate as that of a triangle or a square: since we can put it into a Proposition: since we can compare it with other Ideas on account of its distinctness and determinateness; why should we not be able to range our thoughts about in as clear a method, and with as great perspicuity as about figure and quantity.