HISTORY OF -PHILOSOPHY. 569 



and boldness, referring all authority to the testimony of the senses or 

 experience, and reserving to the powers of reason the privilege of 

 attaining true knowledge. 



In a poem of his which yet remains, and which, like all other phi- 

 losophical works of the time, bears for its title, " On Nature," the 

 first part treats of " truth," or the " unity of that which is." 



In this he asserts, that "that which is, is," that that "which is 

 nought, cannot be conceived, that speech, thought, and being com- 

 pose all that is in reality, that men, blinded by the evidence of 

 their senses, confound that which is with that which is not. There 

 are many causes for believing that that which is never began and 

 cannot cease to be. It is entire, it is one, it is immutable and in- 

 finite. For else, whence was it derived, from what source can it 

 borrow the nourishment for its growth ? Surely not from that which 

 is nought. For who can conceive a power which can make any thing 

 which is not, arise out of a state of non-existence, and appear at a 

 certain moment, neither sooner nor later, ready fashioned and com- 

 plete ? Being must then be eternal, or not be at all : for this maxim 

 is irrefragable, * Nothing can of itself arise out of nothing.' Founded 

 in itself, the universal being rests on itself, and exists permanently. 

 Thought and the object of thought are one ; for there can be no 

 thought without a reality on which it seizes. Those who speak of 

 beginning and end, of change of place and transformation, yield to 

 the suggestions of human prejudice, and employ words destitute of 

 meaning. The form of the whole is perfect : it resembles the sphere, 

 whose centre is equally distant from every part of the surface. There 

 is no void to interrupt the continuity of that which is real." 



The second portion of the work is entitled, " Opinion : " it is a 

 picture of the sensible world, of material nature, a suite of hypotheses 

 on its principles and laws. It assigns two opposing principles to the 

 universe : the one a subtile and ethereal fire ; the other, night. 



Such were the notions of Parmenides, who is usually considered 

 the founder of idealism among the Greeks. 



Two other philosophers of the school of Elea, opposing all doc- 

 trines founded on experience, avowed themselves partisans of the 

 absolute and intelligible unity, Melissus and Zeno. The former con- 

 fines himself to a commentary on the system of Parmenides ; the 

 latter undertook its defence from the attacks made upon it. Me- 

 lissus almost only reproduces the proposition of his predecessor : he 

 asserts that something must exist, for we cannot attribute a quality to 

 a thing without conceiving it real. But that which is real cannot end ; 

 and is infinite, not in space but in duration : it fills up the whole of 

 time and is always like to itself. That space and void are equally 

 impossible. Since what is, is indivisible and composed of parts, he 

 concludes that it cannot admit of form nor dimensions, a consequence 

 of the principle of Xenophanes and Parmenides, which, however, 

 they had not themselves deduced. 



A doctrine which attacked so boldly the general and constant tes- 

 timony of experience, and the evidence of the senses, could not be 

 published without meeting the most energetic contradictions. The 

 instincts of nature and internal consciousness were the opponents set 



