VI.] Chauncey Wright. . 93 



fundamental unit of measurement which is invariable. 

 Without some such constant unit we cannot prove 

 that the order of Nature is uniform : but we cannot 

 prove the constancy of such a unit without referring 

 it to some other unit, and so on for ever ; while to 

 assume the constancy of such a unit is simply to 

 assume the whole case. 



It would seem, therefore, that our belief in the 

 trustworthiness of Nature is not properly described 

 when it is treated simply as a vast induction. It 

 should rather be regarded as a postulate indispensable 

 to the carrying on of rational thought, — a postulate 

 ratified in every act of experience, but without which 

 no act of experience can have any validity or mean- 

 ing. It is for taking this view of the case that Mr. 

 Spencer is charged with rearing a system of philo- 

 sophy upon " undemonstrable beliefs assumed to be 

 axiomatic and irresistible." Considering that the 

 undemonstrable belief in question is simply the beHef 

 in the constancy of Nature, one would be at a loss to 

 see what there is so very heinous in Mr. Spencer's 

 proceeding, were it not obvious that we have here 

 struck upon a grave misconception on the part of Mr. 

 Wright. Misled, no doubt, by some ambiguity of 

 expression, Mr. Wright supposed Mr. Spencer to be 

 laying down some everlasting principle of universal 



