570 HISTORY OF PHILOSOPHY. 



up against this novel system, and thus arose the first regular contro- 

 versy that is met with in the history of philosophy. 



Zeno was the champion who rose up to defend the difficulfposition 

 of the Eleatics. In order to perform this duty in the^. most effective 

 manner, he undertook to attack the enemy on his own ground. He 

 pretended to derive from all phenomena which were perceptible to 

 the senses, and especially from those of motion, a series of paradoxes, 

 which he very artfully put together. Each side seemed more anxious 

 to destroy the system of the other than to defend that which d them- 

 selves professed. This seems to be the course of human nature; 

 for it is more easy to refute the arguments of another than to justify 

 the truth of your own. The following are examples of Zeno's subtle 

 attacks. " Every body," said he, " occupies a space equal to itself. 

 It is every instant at rest. But, if it moves, it must move every 

 instant, or it moves and is at rest at the same time." Again, "If 

 space is a real thing, it must be somewhere : for all that exists must 

 be in some place : therefore this space requires some previous space, 

 and so on to eternity." Zeno endeavoured to prove that absolute unity 

 could not be found in sensible objects, and employed a most inge- 

 nious argument derived from the infinite divisibility of matter. 

 " For," says he, " if you arrive at unity in sensible objects, you will 

 corne to a mathematical point, which has no real existence." 



By this mode of controversy Zeno was led to the invention of 

 logic, which at first was considered rather as the art of disputation 

 than as a direct method of arriving at the truth, which character, 

 indeed, it has constantly preserved, and is made use of now as it was 

 then as a weapon for combat, not as an instrument for investigation. 

 In drawing up the first sketch of this art, Zeno gave it three principal 

 branches : the art of deducing consequences ; the art of conversing ; 

 the art of discussing. 



The first of these branches consists in establishing, by way of sup- 

 position, the two opposite propositions, and then, in attacking the cor- 

 rollaries which result from each, considering it as true. This method 

 Zeno honoured with the name of dianoetic, which implies that it 

 contains the art of thinking well. 



The second method was styled the dialectic, and comprised the art 

 of putting questions and making answers, for which purpose Zeno 

 drew up a set of rules, which had so great a success that the di- 

 dactic form of communicating knowledge, hitherto adopted, was 

 no longer made use of. 



The third division, or the art of discussion, which has been con- 

 founded with the second, consisted of artificial subtleties, the nature 

 of which can be best understood by attending to the following 

 example attributed to Zeno : " Achilles, who was distinguished for 

 his swiftness, could never catch a tortoise. For a body in motion 

 must pass over the given space, and over half the given space. But 

 space is infinitely divisible, like time. Achilles must run over an 

 infinite space before he could come up with the tortoise." 



We perceive that Xenophon, Parmenides, Melissus, and Zeno, 

 form a group by themselves in the annals of philosophy. They all 

 agreed in founding their philosophy on the idea of a real absolute and 



