APPENDIX VI. 



DESCARTES' ACHIEVEMENTS. 



As the short notice we have on Descartes fails to do full justice 

 to this great man, a few more remarks about him will not be 

 inappropriate. 



His influence is twofold : philosophical and scientific. It is 

 easy to detect the consequences of Descartes' philosophy on the 

 one hand, and those of his scientific labours on the other. 



His Philosophy, in the first place, ruined Scholasticism defini- 

 tively ; in the second place, it brought in the taste for psychological 

 analysis, which was to distinguish the age of Louis XIV. ; in the 

 third place, it supplied material for Idealism, Pantheism, Mate- 

 rialism, and Positivism, since it gave birth successively to the 

 philosophy of Malebranche, to Spinoza's, to Leibnitz's, Locke's, 

 Berkeley's, Hume's, Cabanis's, Condillac's, and, through Spinoza, to 

 Kant's, Schelling's, Fichte's, Hegel's, and last, Comte's. 



With reference to Science, he was the first in modern times to 

 sketch the theory of association of ideas (see Aristotle); he dis- 

 covered the theory of reflex action a profound idea which modern 

 science has expounded. He analysed musical sounds geometrically, 

 and found out that the number of vibrations producing the notes 

 are in the inverse ratio of the lengths of the chords; he was the 

 first to maintain that Major Thirds are not discordant but con- 

 cordant. But his greatest scientific feat was mathematical his 

 application of algebra to geometry extended the power of mathe- 

 matics tenfold, and made the road of Newton, Laplace, Legendre, 

 Gauss, and others less arduous to ascend. By his inquiry into the 

 nature of certainty his best known claim upon us " he stands as 

 the founder, not of modern philosophical criticism only, but of 



