44 TWO THEORIES OF KNOWLEDGE 



of things when they were presented to it in per- 

 ceptive Experience. Universalia in re were con- 

 ceived by him as sufficiently explaining the genesis 

 of cognition without the postulation of any such 

 universalia extra rem. 



To the Platonic doctrine he offered the further 

 objection that the eternal forms of things which 

 that doctrine affirmed and which it declared to 

 be represented in their ideal types were necessarily 

 impotential. There was no generative power in 

 the pure activity of Thought. If, therefore, the 

 essentials of Reality were ideal, it followed that 

 they also were impotent, and incapable of causative 

 efficacy. The sensible world, however, was a 

 fluent and perpetually generated stream, which 

 required some potent cause to uphold it. 



The eternal Reality which sustained the world 

 was for him an Energy constantly generating 

 the actual, and no conception which failed to 

 provide for this process of causative generation 

 of the things of Sense could in his view ade- 

 quately account for the phenomena of Nature 

 nor consequently could constitute the system of 

 science. 



In this argument Aristotle undoubtedly expressed 

 a profound truth, but it may perhaps be admitted 



