304 CAUSATION 



in terms of physical quantities we are imparting know- 

 ledge of the response of various metrical indicators to 

 its presence and nothing more" (p. 257). But if a body- 

 is not acting according to strict causality, if there is an 

 element of uncertainty as to the response of the indica- 

 tors, we seem to have cut away the ground for this kind of 

 knowledge. It is not predetermined what will be the 

 reading of the weighing-machine if the body is placed 

 on it, therefore the body has no definite mass; nor where 

 it will be found an instant hence, therefore it has no 

 definite velocity; nor where the rays now being reflected 

 from it will converge in the microscope, therefore it has 

 no definite position; and so on. It is no use answering 

 that the body really has a definite mass, velocity, 

 position, etc., which we are unaware of; that statement, 

 if it means anything, refers to an intrinsic nature of 

 things outside the scope of scientific knowledge. We 

 cannot infer these properties with precision from any- 

 thing that we can be aware of, because the breach of 

 causality has broken the chain of inference. Thus our 

 knowledge of the response of indicators to the presence 

 of the body is non-existent; therefore we cannot assert 

 knowledge of it at all. So what is the use of talking 

 about it? The body which was to be the abstraction of 

 all these (as yet unsettled) pointer readings has become 

 superfluous in the physical world. That is the dilemma 

 into which the old epistemology leads us as soon as we 

 begin to doubt strict causality. 



In phenomena on a gross scale this difficulty can be 

 got round. A body may have no definite position but 

 yet have within close limits an extremely probable 

 position. When the probabilities are large the substitu- 

 tion of probability for certainty makes little difference; 

 it adds only a negligible haziness to the world. But 



