xii ACTIVITY AND SUBSTANCE 207 



But in the philosophy of Herakleitos Nemesis overtakes 

 the Eleatics. Herakleitos affirms against them the ultimate 

 reality of Becoming, the unlimited all-pervading Process, 

 which unremittingly surges in the circling road, the 0805 

 avw KCLTW, wherein all things stream away (irdvra pel ical 

 ovSev /jievei). In spite of the somewhat sinister denial of 

 permanence implied in this addition, Heracliteanism may 

 well have seemed to restore to the universe the life which 

 Eleaticism had made impossible. 



But in Plato the pendulum swings back again to 

 the side of ovaia. Rightly or wrongly, he detected in 

 Heracliteanism consequences which seemed to him fatal 

 to the possibility of knowledge, and instead of seeking 

 to determine the actual limits of the Flux and betaking 

 himself to the practical methods science has since elaborated 

 in order to know it, he preferred to reject Heracliteanism 

 and to propound a revised, and greatly improved, Eleati 

 cism. He points out our need of a TTOV crro&amp;gt;, which is 

 not swept away in the Flux, of a fixed standard whereby 

 to measure and render knowable the flow of Becoming, 

 and in his theory of Ideas he conceived himself to have 

 supplied this demand. In it plurality is, in a manner, 

 recognized in the plurality of the Ideas, united though 

 they are in the Idea of the Good, while the phenomenal 

 world is admitted not to be wholly illusory, being p^era^v 

 rov OVTOS KCU ^ OJ/T05, intermediate between the Ideas 

 and the principle of impermanence, the mystery of which 

 Plato seems to have thought he could resolve by calling 

 it the Non-Existent. 



In the end, however, the Idea remains the only true 

 reality, and the Idea as such is unchanging Being, out 

 of Space and Time. Hence to call anything, e.g., 

 Pleasure, a Becoming (yeveo-i&amp;lt;i) is ipso facto to cast 

 a slur upon its reality and to disqualify it for the position 

 of the Chief Good which must be, he thinks, an abiding 

 ousia. 



In Aristotle the tables are once more turned. To 

 Aristotle the real world, i.e. the world whereof we desire 

 an explanation, is after all the world of change in which 



