66 SCIENCE AND METHOD. 



The observable laws would be much less simple, 

 say all the physicists, if the velocities were regulated 

 by some simple elementary law, if the molecules 

 were, as they say, organised, if they were subject to 

 some discipline. It is thanks to chance — that is to 

 say, thanks to our ignorance, that we can arrive at con- 

 clusions. Then if the word chance is merely synony- 

 mous with ignorance, what does this mean ? Must 

 we translate as follows ? — 



"You ask me to predict the phenomena that will 

 be produced. If I had the misfortune to know the 

 laws of these phenomena, I could not succeed except 

 by inextricable calculations, and I should have to 

 give up the attempt to answer you ; but since I am 

 fortunate enough to be ignorant of them, I will 

 give you an answer at once. And, what is more 

 extraordinary still, my answer will be right." 



Chance, then, must be something more than the 

 name we give to our ignorance. Among the phe- 

 nomena whose causes we are ignorant of, we must 

 distinguish between fortuitous phenomena, about 

 which the calculation of probabilities will give us 

 provisional information, and those that are not for- 

 tuitous, about which we can say nothing, so long 

 as we have not determined the laws that govern 

 them. And as regards the fortuitous phenomena 

 themselves, it is clear that the information that the 

 calculation of probabilities supplies will not cease to 

 be true when the phenomena are better known. 



The manager of a life insurance company does 

 not know when each of the assured will die, but he 

 relies upon the calculation of probabilities and on 

 the law of large numbers, and he does not make a 



