84 SCEPTICISM. 



there Is no change and no process. The process 

 therefore must be a pyschological process in the 

 mind, which travels over .the pre-existing system of 

 mutually-dependent relations, and can only render 

 explicit the relations which were before implicitly 

 involved. That is to say, If our reasoning is cogent, 

 our conclusion ought at the end of the process to 

 appear a petitio .principii .which is Involved In the 

 premisses, and -our conclusion ought to appear 

 nothing new, ex post facto. And the reason is that 

 the supra-sensible world of Ideas Is unaffected by the 

 manipulations by which we catch glimpses of Its 

 correlations, and that its co-existent members have 

 nothing to do with the coming into and passing out 

 of being of the sensible world. ^ 



^ Students of ancient philosophy will have perceived that this 

 account of the contrast betweenireality and thought agrees entirely 

 with Plato's much-maligned description of the world of Ideas. 

 Every one of his assertions is literally true. It is true that the 

 Ideas form a connected hierarchy >which abides unchangeably and 

 eternally "beyond the heavens." It is true that the Idea is the 

 universal, the one opposed to the many which are pervaded by it, 

 and which cannot absorb it. It is true, likewise, that the sensible 

 is knowable only by partaking in the Ideas, that " matter " is the 

 nonexistent, and that the Sensible with its Becoming contains an 

 element of non-existence baffling thought. J^ = The Real is know- 

 able only in terms of thought, and in so far as it is not so express- 

 ible, it is nothing for thought] And Plato is no less eloquently 

 true in his silence than in his explanatioi:is. He does 7iot explain 

 how sensible things " partake in " the Ideas. And the reason is 

 that this partaking is inexplicable, that the connection of thought 

 with reality is just the difficulty, which Plato saw, but which his 

 successors mostly failed to see. If the Sensible and the Idea 

 are fundamentally different, such partaking is an assumption 

 which our knowledge must assume, but which it cannot justify 

 against scepticism. And so Platonism, as its later history 

 showed, is capable of developing in two directions : it may 

 either confess that the connection cannot be made, and so pass 

 into the scepticism of the new Academy, or it must seek extra- 



