ON THE NOTION OF CAUSE 231 



to show that we can never predict what kind of act will 

 be performed. 



Again, his statement of the law of causation is inadequate. 

 The law does not state merely that, if the same cause is 

 repeated, the same effect will result. It states rather that 

 there is a constant relation between causes of certain kinds 

 and effects of certain kinds. For example, if a body falls 

 freely, there is a constant relation between the height 

 through which it falls and the time it takes in falling. It 

 is not necessary to have a body fall through the same 

 height which has been previously observed, in order to 

 be able to foretell the length of time occupied in falling. 

 If this were necessary, no prediction would be possible, 

 since it would be impossible to make the height exactly 

 the same on two occasions. Similarly, the attraction which 

 the sun will exert on the earth is not only known at dis- 

 tances for which it has been observed, but at all distances, 

 because it is known to vary as the inverse square of the 

 distance. In fact, what is found to be repeated is always 

 the relation of cause and effect, not the cause itself ; all 

 that is necessary as regards the cause is that it should be 

 of the same kin a (in the relevant respect) as earlier causes 

 whose effects have been observed. 



Another respect in which Bergson's statement of 

 causation is inadequate is in its assumption that the cause 

 must be one event, whereas it may be two or more events, 

 or even some continuous process. The substantive 

 question at issue is whether mental events are determined 

 by the past. Now in such a case as the repeated reading 

 of a poem, it is obvious that our feelings in reading the 

 poem are most emphatically dependent upon the past, 

 but not upon one single event in the past. All our 

 previous readings of the poem must be included in the 

 cause. But we easily perceive a certain law according to 



