CHANCE. 65 



reserve the right of human free will at least allow 

 determinism to reign undisputed in the inorganic 

 world. Every phenomenon, however trifling it be, 

 has a cause, and a mind infinitely powerful and 

 infinitely well-informed concerning the laws of nature 

 could have foreseen it from the beginning of the ages. 

 If a being with such a mind existed, we could play 

 no game of chance with him ; we should always 

 lose. 



For him, in fact, the word chance would have no 

 meaning, or rather there would be no such thing as 

 chance. That there is for us is only on account of 

 our frailty and our ignorance. And even without 

 going beyond our frail humanity, what is chance 

 for the ignorant is no longer chance for the learned. 

 Chance is only the measure of our ignorance. For- 

 tuitous phenomena are, by definition, those whose 

 laws we are ignorant of 



But is this definition very satisfactory ? When the 

 first Chaldean shepherds followed with their eyes 

 the movements of the stars, they did not yet know 

 the laws of astronomy, but would they have dreamed 

 of saying that the stars move by chance? If a 

 modern physicist is studying a new phenomenon, 

 and if he discovers its law on Tuesday, would he 

 have said on Monday that the phenomenon was 

 fortuitous ? But more than this, do we not often 

 invoke what Bcrtrand calls the laws of chance in 

 order to predict a phenomenon? For instance, in 

 the kinetic theory of gases, we find the well-known 

 laws of Mariotte and of Gay-Lussac, thanks to the 

 hypothesis that the velocities of the gaseous mole- 

 cules vary irregularly, that is to say, by chance. 



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