cessity in this case has certainly never been made manifest. Nevertheless the hypothesis may be admitted, inasmuch as neither the admission nor the rejection of it is of the smallest conceivable importance. Like Dugald Stewart, we reject the question as to the entity in which the admitted phenomena inhere, as altogether unphilosophical; but he and we reject it upon
a certain series of phenomena cannot inhere in a certain admitted substance "matter," and must, therefore be referred to a different substance "mind." Now all reasoning is either a priori or a posteriori. If he reasons in the former of these ways; he forms a priori such a conception of matter that it would involve a contradiction to suppose that the phenomena occasioning the dispute should inhere in it—he first of all fixes for himself a notion of matter, as of something with which certain phenomena are incompatible—something in which they cannot inhere—and then from this conception he deduces the inference that these phenomena are incompatible with matter, or cannot inhere in it—a petitio principii almost too glaring to require notice.—Or does he reason upon this question a posteriori? In this case he professes to found upon no a priori conception of matter, but to be guided entirely by experience. But experience can only inform us what phenomena do or do not inhere in any particular substance; and can tell us nothing about their abstract compatibility or incompatibility with it. We may afterwards infer such compatibility or incompatibility if we please, but we must first of all know what the fact is—or else we may be abstractly arguing a point one way, while the facts go to establish it in the opposite way. In reasoning, therefore, from experience, the question is not, can certain phenomena inhere in a particular substance, or can they not? but we must first of all ask and determine this: do they inhere in it, or do they not? And this, then, now comes to be the question with which the immaterialist, reasoning a posteriori, has to busy himself. Is the negative side of this question to be admitted to him without proof? Are we to permit him to take for granted, that these phenomena do not inhere in matter?—Most assuredly not. He must prove this to be the case, or else he accomplishes nothing—and yet how is it possible for him to prove it? He can only prove it by showing the phenomena to be incompatible with matter—for if he once admits the phenomena to be compatible with matter, then his postulatum of mind is at once disqualified from being advanced. He has given up the attempt to make manifest that necessity for "mind," which it was incumbent upon him to show.
It is, therefore, absolutely necessary to the very life of his argument that he should stickle for the incompatibility of these phenomena with matter. To prove that these phenomena do not inhere in matter, he must show that they cannot inhere in it: This is the only line of argument which is open to him. But then how is he to make good this latter point? We have already seen the inevitable and powerless perplexity in which he lands himself in attempting it. He must, as before, adopt one of two courses. He must either recur to his old a priori trick of framing for himself, first of all, such a conception of matter, that it would be contradictory to suppose the phenomena capable of inhering in it, and then of deducing their incompatibility or contradictoriness from this conception—a mode of proof which certainly shows that the phenomena cannot inhere in his conception of matter, but which by no means proves that they cannot inhere in matter itself. Or he may follow, as before, an a posteriori course. But here, too, we have already shown that such a procedure is impossible, without his taking for granted the very point in dispute. We have already shown that, in adhering to experience, the immaterialist must first of all go and ascertain the fact respecting these phenomena—do they inhere in matter, or do they not—before he is entitled to predicate that they cannot inhere in it, lest while he is steering his argument in one direction, the fact should be giving him the lie in another. We sum up our statement thus: He wishes to prove that certain phenomena cannot inhere in matter. In proving this he is brought to postulate the fact that these phenomena do not inhere in matter; and then, when pressed for a proof of this latter fact, he can only make it good by reasserting that they cannot inhere in matter, in support of which he is again forced to recur to his old statement that they do not inhere in matter,—an instance of circular reasoning of the most perfect kind imaginable. Thus the immaterialist has not given us, and cannot possibly give us any argument at all upon the subject. He has not given us the proof which the "necessity" of the case called for, and which, in admitting the principle of parsimony, he pledged himself to give as the only ground upon which his postulation of a new substance could be justified. He has, after all, merely supplied us with the statement that certain phenomena do not inhere in matter, which is quite sufficiently met on the part of the materialist, by the counter
