D'ALEMBERT. 397 



demonstrative evidence on which it rests, has a tendency 

 to unfit the mind for accurately weighing the inferior 

 kind of proof which alone the other sciences can obtain. 

 Once finding that the certainty to which the geometrician 

 is accustomed cannot be attained, he is apt either to 

 reject all testimony, or to become credulous by confound- 

 ing different degrees of evidence, regarding them all as 

 nearly equal from their immeasurable inferiority to his 

 own species of proof much as great sovereigns con- 

 found together various ranks of common persons, on 

 whom they look down as all belonging to a different 

 species from their own. In this observation there is, 

 no doubt, much of truth, but we must be careful not to 

 extend its scope too far, so as that it should admit of no 

 exceptions. The following life affords one of the most 

 remarkable of these ; as far as physical science went, 

 Laplace afforded another; in several other branches he 

 was, perhaps, no exception to the rule.* 



The hold which their favourite studies have, and keep 

 over geometricians is not the least remarkable proof of 

 the gratification which they are calculated to afford. I 

 well know, to take one instance within my own observa- 

 tion, that my learned and esteemed friend, the present 

 Lord Chancellor, a most successful student of the mathe- 

 matics in his earlier years, reverted to the pursuits in 



* It is said that when the Emperor asked him why he had left 

 out the consideration of a Supreme Intelligence in his speculations, 

 he answered that he conceived he could explain the phenomenon 

 without that hypothesis. But when we look to his demonstration 

 of the high improbability of the system having been formed without 

 an intelligent cause, (above four millions of millions to one he 

 proves it in his Calcul de Probability) we cannot lend much faith to 

 this Paris anecdote. 



