HISTORY OF PHILOSOPHY. 573 



functions, and all its knowledge is acquired from without ; but objects 

 act upon it in two very different manners : bodies, by their violent 

 action on its organs, transmit to it divers impressions; certain media, 

 such as air and water, are necessary for this communication. These 

 impressions, colours, smells, sounds, &c., do not correspond to any 

 real object : they even exist after the body itself has disappeared 

 by the effect of a vibration which is prolonged in our organs. 

 Real objects which are invisible to our senses, namely, atoms, act 

 directly on the understanding, and transmit to it in their passage 

 images of themselves, which serve to retrace them on the spirit. 



In another place he draws a line between the senses and reason. 

 " The first," he says, " are imperfect, obscure, and deceptive : the 

 second all fit for the impress of truth, for atoms, which are the only 

 real objects, are not perceptible to the senses." We here see that 

 Democritus falls back upon the rationalism of the Eleatic metaphy- 

 sicians. 



Empedocles displays in his philosophy a mixture of the tenets of 

 all the schools which preceded him. To the three elements of the 

 lonians he added the earth. Following the example of the Eleatics, 

 he considered these elements as composite matters. The unity of 

 the Pythagorean monad was the first principle in his eyes. He con- 

 sidered the exercise of thought as a function of the physical organs, 

 subjected to all their laws and all their accidents. While he mate- 

 rialized existence, he filled the air with spirits and genii. His 

 principal merit was the having carried to greater extent the ana- 

 lysis of Democritus of sensations. 



Zeno, by defending a bad cause with great skill, attacking the in- 

 stincts of common sense with much art, and designedly multiplying 

 paradoxes, showed by his examples and formulae rather the method 

 of abusing logic by means of subtleties than the method of rendering 

 it a guide to truth. 



The Sophists hastened to profit by these lessons. They were 

 essentially rhetoricians, who taught the art of speaking at a 

 time when all parties in Greece were ambitious of attaining this 

 power. The Sophists made use of the art of reasoning, or rather 

 of disputation ; but they rendered it subordinate to their captious 

 rhetoric, and only used it as a fit instrument to second their views 

 and interests. Zeno armed reason against the senses; Gorgias armed 

 it against itself. He found plausible reasons to prove, 1st, that 

 nothing real exists ; 2d, that, if any thing real did exist, we could 

 not know it ; 3rd, that, if we had any such knowledge, we could not 

 transmit it to others on account of the uncertainty attached .ito'lan- 

 guage. These three maxims served for the three divisions of the book 

 he wrote on Nature. He established these axioms on the strength 

 of the argument drawn from the mobility of all things, and certain 

 subtleties which he presses into his service. 



Protagoras asserts that the understanding, the whole soul, consists 

 in the faculty of sensation. Applying to this hypothesis all that had 

 been said by the Eleatics on the mobility of sensible objects and the 

 relative character of sensation, he is led to results which, though they 

 differ in expression, do not in character, from those of Gorgias. 



