ON THE NOTION OF CAUSE 239 



out, in the end, to be almost all capable of a true inter- 

 pretation ; but they ought all, before being admitted into 

 philosophy, to undergo the ordeal of sceptical criticism. 

 Until they have gone through this ordeal, they are mere 

 blind habits, ways of behaving rather than intellectual 

 convictions. And although it may be that a majority 

 will pass the test, we may be pretty sure that some will 

 not, and that a serious readjustment of our outlook 

 ought to result. In order to break the dominion of 

 habit, we must do our best to doubt the senses, reason, 

 morals, everything in short. In some directions, doubt 

 will be found possible ; in others, it will be checked by 

 that direct vision of abstract truth upon which the possi- 

 bility of philosophical knowledge depends. 



At the same time, and as an essential aid to the direct 

 perception of the truth, it is necessary to acquire fertility 

 in imagining abstract hypotheses. This is, I think, what 

 has most of all been lacking hitherto in philosophy. So 

 meagre was the logical apparatus that all the hypotheses 

 philosophers could imagine were found to be inconsistent 

 with the facts. Too often this state of things led to the 

 adoption of heroic measures, such as a wholesale denial 

 of the facts, when an imagination better stocked with 

 logical tools would have found a key to unlock the 

 mystery. It is in this way that the study of logic becomes 

 the central study in philosophy : it gives the method of 

 research in philosophy, just as mathematics gives the 

 method in physics. And as physics, which, from Plato 

 to the Renaissance, was as unprogressive, dim, and super- 

 stitious as philosophy, became a science through Galileo's 

 fresh observation of facts and subsequent mathematical 

 manipulation, so philosophy, in our own day, is becoming 

 scientific through the simultaneous acquisition of new 

 facts and logical methods. 



