I have made this extract from a very short tract, called Contemplatio Philosophica, by Brook Taylor, which I found in an unpublished memoir of his life printed by the late Sir William Young, in 1793. It bespeaks the clear and acute understanding of this celebrated philosopher, and appears to me an entire refutation of the scholastic argument of Descartes; one more fit for the Anselms and such dealers in words, from whom it came, than for himself.
91. From the idea of a perfect being, Descartes immediately deduced the truth of his belief in an external world, and in the inferences of his reason. For to deceive his creatures would be an imperfection in God; but God is perfect. Whatever, therefore, is clearly and distinctly apprehended by our reason, must be true. We have only to be on our guard against our own precipitancy and prejudice, or surrender of our reason to the authority of others. It is not by our understanding, such as God gave it to us, that we are deceived; but the exercise of our free will, a high prerogative of our nature, is often so incautious as to make us not discern truth from falsehood, and affirm or deny, by a voluntary act, that which we do not distinctly apprehend. The properties of quantity, founded on our ideas of extension and number, are distinctly perceived by our minds, and hence the sciences of arithmetic and geometry are certainly true. But when he turns his thoughts to the phenomena of external sensation, Descartes cannot wholly extricate himself from his original concession, the basis of his doubt, that the senses do sometimes deceive us. He endeavours to reconcile this with his own theory, which had built the certainty of all that we clearly hold certain on the perfect veracity of God.
92. It is in this inquiry that he reaches that important distinction between the primary and secondary properties of matter, the latter being modifications of the former, relative only to our apprehension, but not inherent in things, which, without being wholly new, contradicted the Aristotelian theories of the schools;[232] and he remarked that we are never, strictly speaking, deceived by our senses, but by the inferences which we draw from them.
[232] See Stewart’s First Dissertation on the Progress of Philosophy. This writer has justly observed, that many persons conceive _colour_ to be inherent in the object, so that the censure of Reid on Descartes and his followers, as having pretended to discover what no one doubted, is at least unreasonable in this respect. A late writer has gone so far as to say: “Nothing at first can seem a more rational, obvious, and incontrovertible conclusion, than that the colour of a body is an inherent quality, like its weight, hardness, &c; and that to _see_ the object, and to see it of _its own colour_, when nothing intervenes between our eyes and it, are one and the same thing. Yet this is only a prejudice.” &c. Herschel’s Discourse on Nat. Philos., p. 82. I almost even suspect that the notion of sounds and smells being secondary or merely sensible qualities, is not distinct in all men’s minds. But after we are become familiar with correct ideas, it is not easy to revive prejudices in our imagination. In the same page of Stewart’s Dissertation, he has been led, by dislike of the university of Oxford, to misconceive, in an extraordinary manner, a passage of Addison in the Guardian, which is evidently a sportive ridicule of the Cartesian theory, and is absolutely inapplicable to the Aristotelian.