opera III. remarks on Descartes. 99. Dugald Stewart has justly dwelt on the sig- CHAP. nal service rendered by Descartes to psychological philosophy, by turning the mental vision inward Stewart's upon itself, and accustoming us to watch the tions of our intellect, which, though employed upon ideas obtained through the senses, are as distinguishable from them as the workman from his work. He has given indeed to Descartes a very proud title, Father of the experimental philosophy of the human mind, as if he were to man what Bacon was to nature.* By patient observation of what For he answers the old sophism of Zeno, Quicquid dividi potest in partes infinitas est infinitum, in a manner which does not meet the real truth of the case: Dividi posse in partes infinitas nihil aliud est quam dividi posse in partes quotcunque quis velit. Logica sive Computatio, c. 5. p. 38. (edit. 1667.) * Dissertation on Progress of Philosophy. The word experiment must be taken in the sense of observation. Stewart very early took up his admiration for Descartes. "He was the first philosopher who stated in a clear and satisfactory manner the distinction between mind and matter, and who pointed out the proper plan for studying the intellectual philosophy. It is chiefly in consequence of his precise ideas with respect to this distinction, that we my remark in all his metaphysical writings, a perspicuity which is not observable in those of any of his predecessors." Elem. of Philos. of Human Mind, vol. i. (published in 1792) note A. "When Descartes," he says in the dissertation before quoted, established it as a general principle that nothing conceivable by the power of imagination could throw any light on the operations of thought, a prin- III. CHAP. passed within him, by holding his soul as it were an object in a microscope, which is the only process of a good metaphysician, he became habituated to throw away those integuments of sense which hide us from ourselves. Stewart has censured him for the paradox, as he calls it, that the essence of mind consists in thinking, and that of matter in extension. That the act of thinking is as inseparable from the mind as extension is from matter, cannot indeed be proved; since, as our thoughts are successive, it is not inconceivable that there may be intervals of duration between them; but it can hardly be reckoned a paradox. But whoever should be led by the word essence to suppose, that Descartes confounded the percipient thinking substance, the Ego, upon whose bosom, like that of the ocean, the waves of perception are raised by every breeze of sense, with the perception itself, or even, what is scarcely more tenable, with the reflective action, or thought; that he anticipated this strange paradox of Hume in his earliest work, from which he silently withdrew in his Essays, would not only do great injustice to one of the acutest understandings that ever came to the subject, but overlook several clear assertions of the distinction, especially in his answer to Hobbes. "The thought," he says, "differs from that which thinks, as the mode from the substance." And Stewart has in his earliest work * Vol. i. p. 470. Arnaud objected, in a letter to Descartes, Comment se peut il faire que la pensée constitue l'essence de l'esprit, puisque l'esprit est une substance, et que la pensée semble n'en être qu'un mode? Descartes replied that thought in general, la pensée, ou la nature qui pense, in which he placed the essence of the soul, was very different from such or such particular acts of thinking, vol. vi. p. 153. 160. justly corrected Reid in this point as to the Carte- CHAP. sian doctrine.* III. of Descartes. 100. Several singular positions which have led to Paradoxes an undue depreciation of Descartes in general as a philosopher, occur in his metaphysical writings. Such was his denial of thought, and, as is commonly said, sensation to brutes, which he seems to have founded on the mechanism of the bodily organs, a cause sufficient, in his opinion, to explain all the phænomena of the motions of animals, and to obviate the difficulty of assigning to them immaterial souls t; his rejection of final causes in the explana *Philosophy of Human Mind, vol. i. note A. See the Principia, § 63. + It is a common opinion that Descartes denied all life and sensibility to brutes. But this seems not so clear. Il faut remarquer, he says in a letter to More, where he has been arguing against the existence in brutes of any thinking principle, que je parle de la pensée, non de la vie, ou du sentiment; car je n'ôte la vie à aucun animal, ne la faisant consister que dans la seule chaleur du cœur. Je ne leur refuse pas même le sentiment autant qu'il dépend des organes du corps. vol. x. p. 208. In a longer passage, if he does not express himself very clearly, he admits passions in brutes, and it seems impossible that he could have ascribed passions to what has no sensation. Much of what he here says is very good. Bien que Montaigne et Charron aient dit, qu'il y a plus de différence d'homme à homme que d'homme à bête, il n'est toutefois jamais trouvé aucune bête si parfaite, qu'elle ait usé de quelque signe pour faire entendre à d'autres animaux quelque chose que n'eût point de rap- III. CHAP. tion of nature, as far above our comprehension, and unnecessary to those who had the internal proof of God's existence; his still more paradoxical tenet that the truth of geometrical theorems, and every other axiom of intuitive certainty, depended upon the will of God; a notion that seems to be a relic of his original scepticism, but which he pertinaciously defends throughout his letters.* From remarkable errors men of original and independent genius are rarely exempt; Descartes had pulled down an edifice constructed by the labours of near two thousand years, with great reason in many respects, yet perhaps with too unlimited a disregard of his predecessors; it was his destiny, as it had been theirs, to be sometimes refuted and depreciated in his turn. But the single fact of his having ne sont pas fort differens des paradox with the arguments which common sense furnishes. He would even have preferred ascribing immortality to them, as many ancient philosophers did. But surely Descartes, who did not acknowledge any proofs of the immortality of the human soul to be valid, except those founded on re velation, needed not to trouble himself much about this difficulty. * C'est en effet parler de Dieu comme d'un Jupiter ou d'un Saturne, et l'assujettir au Styx et aux destinées, que de dire que ces vérités sont indépendantes de lui. Ne craignez point, je vous prie, d'assurer et de publier partout que c'est Dieu qui a établi ces lois en la nature, ainsi qu'un roi établit les lois en son royaume. vol. vi. p. 109. He argues as strenuously the same point in p. 132. and p. 307. III. first established, both in philosophical and popular CHAP. belief, the immateriality of the soul, were we even to forget the other great accessions which he made to psychology, would declare the influence he has had on human opinion. From this immateriality, however, he did not derive the tenet of its immortality. He was justly contented to say that from the intrinsic difference between mind and body, the dissolution of the one could not necessarily take away the existence of the other, but that it was for God to determine whether it should continue to exist; and this determination, as he thought, could only be learned from his revealed will. The more powerful arguments, according to general apprehension, which reason affords for the sentient being of the soul after death, did not belong to the metaphysical philosophy of Descartes, and would never have been very satisfactory to his mind. He says, in one of his letters, that "laying aside what faith assures us of, he owns that it is more easy to make conjectures for our own advantage and entertain promising hopes, than to feel any confidence in their accomplishment." * tion of de 101. Descartes was perhaps the first who saw His just nothat definitions of words, already as clear as they finitions. can be made, are nugatory or impenetrable. This alone would distinguish his philosophy from that of the Aristotelians, who had wearied and confused themselves for twenty centuries with unintelligible endeavours to grasp by definition what refuses to be defined. "Mr. Locke," says Stewart, "claims * Vol. ix. p. 369. |