THE LIMITS OF EVOLUTION 23 



course it cannot be by sense, for the object is super- 

 sensible ; how, then, is it managed ? We get this 

 answer : We know the truth that the Unknowable 

 exists, by the criterion of all truth, namely, the "in- 

 conceivability of the opposite." But if this criterion 

 really says anything in support of genuine certainty, 

 it says that a pure conception of the mind, going 

 quite beyond the literal testimony of sense, is objec- 

 tively valid, in and of itself. 



Manifestly, the only way of escape from this very 

 awkward conclusion, so plainly contradictory of the 

 prime thesis that our knowledge rests on sense alone 

 and is confined to things of sense, is to say that in- 

 conceivability means nothing but the incapacity Wa\c\\ 

 limited experience begets in us — our impotence to 

 think beyond the bounds built for us by the accumu- 

 lated pressure of hereditary impressions. But here, 

 if we would maintain the empiricist theory of know- 

 ledge in its consistent integrity, we are confronted 

 with two difficulties : (i) How can impotence to pass 

 the limits of experience suddenly be transformed into 

 power to pass them and pierce to a Noumenon, even 

 as barely existent } (2) How can our incapability of 

 conceiving the opposite of existence for the Noume- 

 non mean anything more than that we are so hemmed 

 in by the massed result of our sense-impressions as 

 to be incapable of releasing our thoughts from their 

 mould.'* — that we must think as sense compels us, 



