i INDIVIDUALITY AND AGE 21 



unorganized matter are expressible, in principle, by 

 differential equations in which time (in the sense in 

 which the mathematician takes this word) would play 

 the r61e of independent variable. Is it so with the 

 laws of life ? Does the state of a living body find its 

 complete explanation in the state immediately before ? 

 Yes, if it is agreed a priori to liken the living body to 

 other bodies, and to identify it, for the sake of the 

 argument, with the artificial systems on which the 

 chemist, physicist, and astronomer operate. But in 

 astronomy, physics, and chemistry the proposition has 

 a perfectly definite meaning : it signifies that certain 

 aspects of the present, important for science, are 

 calculable as functions of the immediate past. Nothing 

 of the sort in the domain of life. Here calculation 

 touches, at most, certain phenomena of organic 

 destruction. Organic creation^ on the contrary, the 

 evolutionary phenomena which properly constitute life, 

 we cannot in any way subject to a mathematical treat 

 ment. It will be said that this impotence is due only 

 to our ignorance. But it may equally well express 

 the fact that the present moment of a living body does 

 not find its explanation in the moment immediately 

 before, that all the past of the organism must be 

 added to that moment, its heredity in fact, the whole 

 of a very long history. In the second of these two 

 hypotheses, not in the first, is really expressed the 

 present state of the biological sciences, as well as their 

 direction. As for the idea that the living body might 

 be treated by some superhuman calculator in the 

 same mathematical way as our solar system, this has 

 gradually arisen from a metaphysic which has taken a 

 more precise form since the physical discoveries of 

 Galileo, but which, as we shall show, was always the 



