38 Note to Rev. W. V. Harcourt's Letter 



which I have thrown fifty times with the like result will con- 

 tinue to show the same face fifty times more. 



The distinction between the two cases is evidently no other 

 than this. In the latter I have inferred an invariable cause, 

 namely that of weight, as determining the event; in the 

 former 1 have inferred that causes are operating, which I pre- 

 sume from the frequent recurrence of the event to operate with 

 some degree of permanence, but of which the duration, till I can 

 trace the laws and circumstances which govern the eruptions 

 of volcanoes, is so doubtful and incalculable, that the cessa- 

 tion of the event is almost as likely as its continuance. 



The ebb and flow of the tide, the rising and setting of the 

 sun, suggest the same kind of thoughts as the determinate fall 

 of the die : only in these cases it is the generality of the phe- 

 nomena rather than their 'precision which guides the mind to 

 its conclusion that here is a law of nature — a conclusion which 

 once arrived at, from however few observations, produces a 

 certainty that the event will continue, equal to the observa- 

 tion of ages. 



But the amount of rational certainty is carried much fur- 

 ther, when the mind rises to the consideration of a geome- 

 trical path for the sun or the earth, and has ascertained those 

 precise and universal laws which regulate the movements of 

 the heavenly bodies. By whatever means this knowledge is 

 obtained, the assurance of the future event is carried by it to 

 the highest pitch, and that often after very few observations 

 indeed ; as any one will see, who considers the great degree 

 of certainty which a few sights of a comet, if we abstract the 

 chance of disturbing forces, can give of its periodical return. 



In all these cases it is evident that the real medium through 

 which we connect the actual with the future is the apprehension 

 of an efficient, and if we would probe the subject to the bottom, 

 an intelligent cause. This is the principle, issuing from the 

 inward analogies of our own minds, which lies at the founda- 

 tion of philosophy, and gives force to inductive evidence ; this 

 is the principle which turns sequences into causes and effects, 

 gathers individual facts into laws, and connects, so far as it is 

 possible to connect, the past, the present, and the future. 



Those who clearly perceive the truth here stated, will see 

 that there is not the least ground for considering our expec- 

 tation of the rising of the sun as an ultimate fact in the consti- 

 tution of our minds, or for resolving a reasonable belief into an 

 instinctive and implicit credulity in the continuance of the laws 

 of nature. 



What the instinctive process may be by which irrational 



