THE MECHANISM OF NATURE 301 



not merely antecedent or prior in time to what we call its effect; 

 it is so related to the effect that if it or its equivalent event had 

 not happened, the effect would not have happened. Anything in 

 the absence of which a phenomenon woiild not have come to pass 

 is a cause in the ordinary sense." 



No one can object to this analysis of the ordinary sense of 

 the word cause, if not only this word but all the words I have 

 put in italics are used in the ordinary sense; but when using 

 words in this sense, we say one event would not have happened 

 in the absence of another, we mean only that belief that it might 

 so happen seems inconsistent with what we chance to know of 

 the past, and with those responses which we make in virtue of 

 our nature. There may be no practical difference between cer- 

 tainty and this expectation, if it is shared by all persons in whom 

 we have confidence, if every experiment which has tested it has 

 verified it, if it is associated in our minds with other events re- 

 garding which we have the same confidence, and if our organic 

 'responses are so firmly adjusted to this association that we fail 

 to discover any way to change them without disaster. Thus put, 

 the analysis of the word cause is seen to have no bearing, either 

 positively or negatively, upon the existence of a necessary law 

 of causation; but it seems to me to be all science warrants, for 

 our ability to believe in the order of nature changes daily with 

 our knowledge and experience, and our organic responses change 

 slowly through selection. 



Perception of the truth that our knowledge of the world around 

 us is knowledge of the order of events, and that we know no reason 

 why events should be orderly except that the fact is so, is, in effect, 

 an admission that all our knowledge of nature is sensible know- 

 ledge. Whether they agree with Berkeley that objects of sense, 

 or, as he prefers to call them, ideas, are all that exist, most thought- 

 ful men of science agree that they are all we know the exist- 

 ence of. 



" Ideas which are observed to be connected together are," as 

 Berkeley points out, " vulgarly considered under the relation of 

 cause and effect, whereas, in strict and philosophic truth, they are 

 only related as the sign and the thing signified" (13). 



