184 MYSTICISM AND LOGIC 



The second definition need not detain us long, for two 

 reasons. First, because it is psychological : not the 

 ' thought or perception ' of a process, but the process 

 itself, must be what concerns us in considering causality. 

 Secondly, because it is circular : in speaking of a process 

 as " taking place in consequence of " another process, it 

 introduces the very notion of cause which was to be 

 denned. 



The third definition is by far the most precise ; indeed 

 as regards clearness it leaves nothing to be desired. But 

 a great difficulty is caused by the temporal contiguity of 

 cause and effect which the definition asserts. No two 

 instants are contiguous, since the time-series is compact ; 

 hence either the cause or the effect or both must, if the 

 definition is correct, endure for a finite time ; indeed, by 

 the wording of the definition it is plain that both are 

 assumed to endure for a finite time. But then we are 

 faced with a dilemma : if the cause is a process involving 

 change within itself, we shall require (if causality is uni- 

 versal) causal relations between its earlier and later parts ; 

 moreover, it would seem that only the later parts can be 

 relevant to the effect, since the earlier parts are not 

 contiguous to the effect, and therefore (by the definition) 

 cannot influence the effect. Thus we shall be led to 

 diminish the duration of the cause without limit, and 

 however much we may diminish it, there will still 

 remain an earlier part which might be altered without 

 altering the effect, so that the true cause, as denned, will 

 not have been reached, for it will be observed that the 

 definition excludes plurality of causes. If, on the other 

 hand, the cause is purely static, involving no change 

 within itself, then, in the first place, no such cause is to 

 be found in nature, and in the second place, it seems 

 strange too strange to be accepted, in spite of bare 



