230 SCIENTIFIC METHOD IN PHILOSOPHY 



have occurred at any earlier time, and is therefore neces- 

 sarily quite different from all previous and subsequent 

 events. If, for example, I read a certain poem many 

 times, my experience on each occasion is modified by the 

 previous readings, and my emotions are never repeated 

 exactly. The principle of causation, according to him, 

 asserts that the same cause, if repeated, will produce the 

 same effect. But owing to memory, he contends, this 

 principle does not apply to mental events. What is 

 apparently the same cause, if repeated, is modified by the 

 mere fact of repetition, and cannot produce the same 

 effect. He infers that every mental event is a genuine 

 novelty, not predictable from the past, because the past 

 contains nothing exactly like it by which we could imagine 

 it. And on this ground he regards the freedom of the 

 will as unassailable. 



Bergson's contention has undoubtedly a great deal of 

 truth, and I have no wish to deny its importance. But 

 I do not think its consequences are quite what he believes 

 them to be. It is not necessary for the determinist to 

 maintain that he can foresee the whole particularity of 

 the act which will be performed. If he could foresee 

 that A was going to murder B, his foresight would not 

 be invalidated by the fact that he could not know all the 

 infinite complexity of A's state of mind in committing 

 the murder, nor whether the murder was to be performed 

 with a knife or with a revolver. If the kind of act which 

 will be performed can be foreseen within narrow limits, 

 it is of little practical interest that there are fine shades 

 which cannot be foreseen. No doubt every time the 

 story of the grouse in the gun-room is told, there will 

 be slight differences due to increasing habitualness, but 

 they do not invalidate the prediction that the story will 

 be told. And there is nothing in Bergson's argument 



