220 SCIENTIFIC METHOD IN PHILOSOPHY 



causal laws, we have not hitherto introduced the word 

 " cause." At this stage, it will be well to say a few words 

 on legitimate and illegitimate uses of this word. The word 

 " cause," in the scientific account of the world, belongs 

 only to the early stages, in which small preliminary, ap- 

 proximate generalisations are being ascertained with a 

 view to subsequent larger and more invariable laws. We 

 may say, " Arsenic causes death," so long as we are 

 ignorant of the precise process by which the result is 

 brought about. But in a sufficiently advanced science, 

 the word " cause " will not occur in any statement of 

 invariable laws. There is, however, a somewhat rough 

 and loose use of the word " cause ' which may be pre- 

 served. The approximate uniformities which lead to its 

 pre-scientific employment may turn out to be true in all 

 but very rare and exceptional circumstances, perhaps in 

 all circumstances that actually occur. In such cases, it is 

 convenient to be able to speak of the antecedent event 

 as the " cause " and the subsequent event as the " effect. " 

 In this sense, provided it is realised that the sequence is 

 not necessary and may have exceptions, it is still- possible 

 to employ the words " cause ' and " effect." It is in this 

 sense, and in this sense only, that we shall intend the 

 words when we speak of one particular event " causing " 

 another particular event, as we must sometimes do if we 

 are to avoid intolerable circumlocution. 



III. We come now to our third question, namely : 

 What reason can be given for believing that causal laws 

 will hold in future, or that they have held in unobserved 

 portions of the past ? 



What we have said so far is that there have been 

 hitherto certain observed causal laws, and that all the 

 empirical evidence we possess is compatible with the 

 view that everything, both mental and physical, so far 



