“The former, or corporeal species which must be in the brain in order to imagination, are not thoughts; but the operation of the mind imagining or turning towards these species, is a thought.”—Ep. p. II liv. (De Pass. p.1., art. 35. Appendix, Def. II, p. 229).
These and similar passages might seem, at first sight, to countenance the supposition that Descartes admitted a knowledge of the corporeal species or organic impression. Such an interpretation is, however, rash and untenable, were there no other ground for rejecting it, save the various contradictions of the principles of the philosophy of which it is supposed to form a part, for these are so many and so manifest, that we could hardly suppose such a thinker as Descartes to have allowed them to escape his notice. Before showing that the passages in themselves do not really warrant the interpretation here referred to, I shall point out its general inconsistency, not only with the main principle, but with certain particular doctrines of Cartesianism, and these the most important and distinctive.
In the first place, then, had Descartes admitted a knowledge of the material impression, either in sense or imagination, and, be it observed, an immediate knowledge is the only supposable, he must have allowed an immediate consciousness of matter, for the corporeal species is a material object. But this would have been to contradict the fundamental principle of his philosophy, according to which, mind, on account of its absolute diversity from body, is supposed to be able to hold no immediate converse with matter, but only to be cognisant of it by means of its own modifications, determined hyperphysically on occasion of certain affections of the body with which it is conjoined. And thus, if the mind be immediately cognisant of the corporeal species, what occupies the prominent and distinctive place in Cartesianism—viz., the host of mental ideas representative of the outward object, becomes forthwith the superfluity and excrescence of the system; for if the mind can take immediate cognisance of the corporeal species, i.e. of matter, why postulate a mental representation in order to the perception of the outward object?
But, in the second place, whether the material impression be an object of consciousness or not, Descartes must still be held to allow the existence of a mental modification or idea. The species, therefore, on the hypothesis that it is an object of consciousness is either really identical with the mental idea, or it is different from it. To take the former supposition, or that of the identity of the material and mental modifications, it will follow that mind and matter are no longer distinguishable, are no longer diverse substances, seeing their modifications coincide—a tenet no less at variance with the entire course of the speculations of Descartes, than is the doctrine from which it flows with the numerous explicit statements, in which he declares the total diversity of the material and mental ideas, as modifications of substances in themselves distinct. But the organic impression, if not identical with, must be diverse from, the mental idea. Now as, on the hypothesis in question, the material idea is perceived, and as the mental is likewise an object of perception, there must be in each of the faculties of sense and imagination a twofold object. For such a doctrine, there is not the shadow of a ground in all the writings of Descartes.
But, in the third place, let it be supposed that Descartes did not allow the existence of mental ideas at all, and therefore only a single object in perception, and that the organic impression, even with this gratuitous allowance a palpable contradiction in the doctrine of the philosopher would arise. The organic impression, in order to constitute the representative idea of the object, must represent the object, not suggest it or represent it materially (materialiter), as a natural sign, for the object could not be simply suggested to the mind or thus represented, without appearing in a mental modification or idea, which is contrary to the hypothesis. But an object that is material, and at the same time representative, must, if it represent by itself, represent intentionally (intentionaliter); in other words, it must resemble the object it represents, or be the image or likeness of it. It is the property of mind alone to be capable of representing something different from itself, or even quite opposed, in a modification not at all resembling the thing represented; as, for example, an extended object in an unextended modification. But the resemblance of the material idea to the outward object, is a doctrine explicitly denied by Descartes.—(Vide Remarks on Programme of Regius, quoted above, Prin. of Phil., P. IV, §§ 197, 198.)
But, finally, the whole hypothesis makes Descartes contradict not only his own doctrine of representation, but destroy the general conditions of any representative doctrine whatever: for, as the only ground on which a doctrine of representation can be supposed necessary, is that the mind is not immediately percipient of the outward object, if Descartes at the same time holds that the representation, itself material and an object external to the mind, because existing in the brain, is perceived, he must allow to the mind, at first hand, that power on the denial of the existence
