iii.i LAWS AND GENERA 229 



two terms is inverted: laws are no longer reduced to genera, 

 but genera to laws; and science, still supposed to be 

 uniquely one, becomes altogether relative, instead of 

 being, as the ancients wished, altogether at one with 

 the absolute. A noteworthy fact is the eclipse of the 

 problem of genera in modern philosophy. Our theory 

 of knowledge turns almost entirely on the question of 

 laws: genera are left to make shift with laws as best 

 they can. The reason is, that modern philosophy has 

 its point of departure in the great astronomical and physical 

 discoveries of modern times. The laws of Kepler and of 

 Galileo have remained for it the ideal and unique type 

 of all knowledge. Now, a law is a relation between things 

 or between facts. More precisely, a law of mathematical 

 form expresses the fact that a certain magnitude is a 

 function of one or several other variables appropriately 

 chosen. Now, the choice of the variable magnitudes, 

 the distribution of nature into objects and into facts, has 

 already something of the contingent and the conventional. 

 But, admitting that the choice is hinted at, if not prescribed, 

 by experience, the law remains none the less a relation, 

 and a relation is essentially a comparison; it has objective 

 reality only for an intelligence that represents to itself 

 several terms at the same time. This intelligence may be 

 neither mine nor yours: a science which bears on laws may 

 therefore be an objective science, which experience con- 

 tains in advance and which we simply make it disgorge; 

 but it is none the less true that a comparison of some kind 

 must be effected here, impersonally if not by any one 

 in particular, and that an experience made of laws, that 

 is, of terms related to other terms, is an experience made of 

 comparisons, which, before we receive it, has already had to 

 pass through an atmosphere of intellectuality. The idea 

 of a science and of an experience entirely relative to the 



