[244] 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 may 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 principle which I consider as exclusively his own, he laid the foundations of the experimental philosophy of the human mind. That the same truth had been previously perceived more or less distinctly by Bacon and others, appears probable from the general complexion of their speculations; but which of them has expressed it with equal precision, or laid it down as a fundamental maxim in their logic?” The words which I have put in italics seem too vaguely and not very clearly expressed, nor am I aware that they are borne out in their literal sense, by any position of Descartes; nor do I apprehend the allusion to Bacon. But it is certain that Descartes, and still more his disciples Arnauld and Malebranche, take better care to distinguish what can be imagined from what can be conceived or understood, than any of the school of Gassendi in this or other countries. One of the great merits of Descartes as a metaphysical writer, not unconnected with this, is that he is generally careful to avoid figurative language in speaking of mental operations, wherein he has much the advantage over Locke. [245] Vol. i., p. 470. Arnauld 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 que 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. [246] Philosophy of Human Mind, vol. i., note A. See the Principia, § 63. |Paradoxes of Descartes.|