ON THE NOTION OF CAUSE 221 



as our observation has extended, has happened in accord- 

 ance with causal laws. The law of universal causation, 

 suggested by these facts, may be enunciated as follows : 



"There are such invariable relations between different 

 events at the same or different times that, given the state 

 of the whole universe throughout any finite time, however 

 short, every previous and subsequent event can theoreti- 

 cally be determined as a function of the given events 

 during that time." 



Have we any reason to believe this universal law ? 

 Or, to ask a more modest question, have we any reason 

 to believe that a particular causal law, such as the law of 

 gravitation, will continue to hold in the future ? 



Among observed causal laws is this, that observation of 

 uniformities is followed by expectation of their recurrence. 

 A horse who has been driven always along a certain road 

 expects to be driven along that road again ; a dog who is 

 always fed at a certain hour expects food at that hour 

 and not at any other. Such expectations, as Hume 

 pointed out, explain only too well the common-sense 

 belief in uniformities of sequence, but they afford ab- 

 solutely no logical ground for beliefs as to the future, 

 not even for the belief that we shall continue to expect 

 the continuation of experienced uniformities, for that is 

 precisely one of those causal laws for which a ground has 

 to be sought. If Hume's account of causation is the 

 last word, we have not only no reason to suppose that 

 the sun will rise to-morrow, but no reason to suppose 

 that five minutes hence we shall still expect it to rise 

 to-morrow. 



It may, of course, be said that all inferences as to the 

 future are in fact invalid, and I do not see how such 

 a view could be disproved. But, while admitting the 

 legitimacy of such a view, we may nevertheless inquire : 



