i88 MYSTICISM AND LOGIC 



less than a certain thickness, the glass breaks. I also do 

 not deny that the observation of such regularities, even 

 when they are not without exceptions, is useful in the 

 infancy of a science : the observation that unsupported 

 bodies in air usually fall was a stage on the way to the 

 law of gravitation. What I deny is that science assumes 

 the existence of invariable uniformities of sequence of 

 this kind, or that it aims at discovering them. All such 

 uniformities, as we saw, depend upon a certain vagueness 

 in the definition of the "events." That bodies fall is a 

 vague qualitative statement ; science wishes to know 

 how fast they fall. This depends upon the shape of the 

 bodies and the density of the air. It is true that there is 

 more nearly uniformity when they fall in a vacuum ; so 

 far as Galileo could observe, the uniformity is then com- 

 plete. But later it appeared that even there the latitude 

 made a difference, and the altitude. Theoretically, the 

 position of the sun and moon must make a difference. 

 In short, every advance in a science takes us farther 

 away from the crude uniformities which are first observed, 

 into greater differentiation of antecedent and consequent, 

 and into a continually wider circle of antecedents recog- 

 nised as relevant. 



The principle " same cause, same effect," which philo- 

 sophers imagine to be vital to science, is therefore utterly 

 otiose. As soon as the antecedents have been given 

 sufficiently fully to enable the consequent to be calcu- 

 lated with some exactitude, the antecedents have be- 

 come so comphcated that it is very unlikely they will 

 ever recur. Hence, if this were the principle involved, 

 science would remain utterly sterile. 



The importance of these considerations lies partly m 

 the fact that they lead to a more correct account of 

 scientific procedure, partly in the fact that they remove 



