aS4 Professor Stewart's History of the Progress of Philosophy. 



enmmon logical error of attempting to 

 define woriis which express notions too 

 »iniple to admit of" analysis. Mr. Locke 

 claiias this jmprovennent as entirely his 

 o«n ; but the merit of it unquestionably 

 belongs tn Descartes, alihoui^h it must 

 be owned that he has not always suffici- 

 ently attended to it in liis own re- 

 Bearches. 



2. Ilis observations on the different 

 classes of our prejudices; particularly on 

 "the errors to which we are liable in con- 

 sequence of a careless use of language as 

 the instriimtnt of lhoui;ht. The greater 

 part of these observations, if not the 

 whole, had been previously hinted at by 

 Bacon; but they are expressed by Des- 

 cartes with greater precision and sii-.ipli 



the pineal gland or conarion, is knoMrn 

 to every one who has perused the "Al- 

 ma" of Prior. It is not, perhaps, equally 

 known that the circumstance which deter* 

 mined him to fix on this particular spot, 

 was the very plausible consideration that, 

 among the dilTerent parts of the brain, 

 tiiis was the only one he could find, 

 which, being single and central, was fit- 

 ted for the habitation of a being, of which 

 he conceived unity and indivisibility to 

 be e»sential and obvious attributes. In 

 what manner the animal spirits, by their 

 motions forwards and backwards in the 

 nervous tubes, keep up the comniunica* 

 lion between this gland and the different 

 parts of the body, so as to produce the 

 phenomena of perceptioti, memory, ima- 



city, and in a style better adapted to the gination, aiUl muscular motion, he has 



taste of the present age. 



3. The paramount and indispntable 

 authority which, in all our reasonings 

 concerning the human mind, he ascribes 

 to the evidence of consciousness. Of 

 this logical principle he has availed him- 

 «elf, with irresistible force, in refuting 

 the scholastic sophisms against the liberty 

 of human actions, drawn from the pre- 

 science of the Deity, and other conside- 

 rations of ft theological nature 



attempted particularly to explain; de- 

 scribing the processes by which these 

 various effects are .icconiplished, with as 

 decisive a tone of authority as if he had 

 been demonstrating experimentally the 

 circulation of the blood. How curious 

 to meet with such speculations in the 

 works of the same philosopher who had 

 so clearly perceived the necessity, ia 

 studying the laws of iMind, of abstracting 

 entirely from the analogies ijf Matter; 



4, The most important, however, of and who, at the outset of his inquiries. 



bH his improvements in metaphysics, is 

 the distinction which he has so clearly 

 and so strongly drawn between the pri- 

 ntary and the sceondury qualities of 

 matter. This distinction was not un- 

 known to some of the ancient schools of 

 philosophy in Greece; hut it was after- 

 wards rejected by Aristotle, and by the 

 schoolmen ; and it was reserved for 

 Descartes to place it in such a light as 

 (with the exception of a very lew scep- 

 tical or rather' paradoxical theorists) to 

 unite the opinions of all succeeding in- 

 quirers. For this step, so apparently 

 easy, but so momentous in its conse- 

 quences, Descartes was not indebted to 

 any long or difficult processes of renson- 

 '\i\c ; hut to those habits of accurate and 

 patient attention to rhe operations of his 

 own nimd, which, from his early years, 

 it was the creat business of bis life to 

 cultivate. It may be proper to add, 

 that the epithets primujy and secondary, 

 now universally employed to mark the 

 distinction in question, were first intro. 

 duced by Locke; a circumstance which 

 may have contributed to throw into the 

 shade the tnerits of tliose enquirers who 

 had previously struck into the same 

 path. 



The hypothesis of Descartes, which 



had carried his scepticism so far as to 

 require a proof even of the existence of 

 his own body ! To those, however, who 

 reflect with attention on the method 

 adopted by Descartes, this inconsistency 

 will not appear so inexplicable as at first 

 sight may be imagined ; insomuch as the 

 same scepticism which led him to sus> 

 pend his faith in his intellectual faculties 

 till he had once proved to his satisfaction, 

 from the necessary veracity of God, that 

 these faculties were to be regarded as 

 the divine oracles, prepared him, in all 

 the subsequent steps of his progress, to 

 listen to tlie suggestions of his own falli- 

 ble judgment with more than comraoa 

 credulity and confidence. 

 CASS E> or. 

 Among the opponents of Descartes, 

 Gassendi was one of the earliest, and by 

 far the most formidable. No two philo> 

 sophers were ever more strongly con- 

 trasted, both in point of talents and of 

 temper ; the former as far superior to 

 the latter in originality of genius — in 

 powers of concentrated attention to the 

 phenomena of the internal world — in 

 classical taste — in moral sensibility, and 

 in all the rarer gifts of the mind, as he 

 fell short of him in erudition — in industry 

 as a book-maker — in the Justness of his 



assigns to the so»l for its principal seat logical views, so far as the phenomena of 

 ** - 1 th« 



