Ah!—“Ability or inability to conceive,” says Mr. Mill, very properly, “is in no case to be received as a criterion of axiomatic truth.” What modern in his senses would ever think of disputing this truism? The only wonder with us must be, how it happened that Mr. Mill conceived it necessary even to hint at any thing so obvious. So far good—but let us turn over another paper. What have we here?—“Contradictories cannot both be true—that is, cannot co-exist in nature.” Here Mr. Mill means, for example, that a tree must be either a tree or not a tree—that it cannot be at the same time a tree and not a tree. Very well; but I ask him why. His reply is this—and never pretends to be any thing else than this—“Because it is impossible to conceive that contradictories can both be true.” But this is no
