166 MYSTICISM AND LOGIC 



the thing, the less its appearance is affected by the inter- 

 vening matter. As we travel further and further from the 

 thing, its appearances diverge more and more from their 

 initial character ; and the causal laws of their divergence 

 are to be stated in terms of the matter which lies between 

 them and the thing. Since the appearances at very small 

 distances are less affected by causes other than the thing 

 itself, we come to think that the limit towards which these 

 appearances tend as the distance diminishes is what the 

 thing " really is," as opposed to what it merely seems to 

 be. This, together with its necessity for the statement of 

 causal laws, seems to be the source of the entirely erro- 

 neous feeling that matter is more "real" than sense- 

 data. 



Consider for example the infinite divisibility of matter. 

 In looking at a given thing and approaching it, one sense- 

 datum will become several, and each of these will again 

 divide. Thus one appearance may represent many things, 

 and to this process there seems no end. Hence in the 

 limit, when we approach indefinitely near to the thing, 

 there will be an indefinite number of units of matter 

 corresponding to what, at a finite distance, is only one 

 appearance. This is how infinite divisibility arises. 



The whole causal efficacy of a thing resides in its matter. 

 This is in some sense an empirical fact, but it would be hard 

 to state it precisely, because " causal efficacy " is difficult 

 to define. 



What can be known empirically about the matter of a 

 thing is only approximate, because we cannot get to know 

 the appearances of the thing from very small distances, 

 and cannot accurately infer the limit of these appearances. 

 But it is inferred approximately by means of the appear- 

 ances we can observe. It then turns out that these 

 appearances can be exhibited by physics as a function of 



