no THE GRAMMAR OF SCIENCE 



natural phenomena, but he is content to think that this 

 reason may be his own till he discovers evidence to the 

 contrary. He recognises that the so-called law of nature 

 is but a simple resume, a brief description of a wide range 

 of his own perceptions, and that the harmony between his 

 perceptive and reasoning faculties is not incapable of being 

 traced to its origin. Natural law appears to him an 

 intellectual product of man, and not a routine inherent in 

 " dead matter." The progress of science is thus reduced 

 to a more and more complete analysis of the perceptive 

 faculty — an analysis which unconsciously and not un- 

 naturally, if illogically, we too often treat as an analysis 

 of something beyond sense-impression. Thus both the 

 material and the laws of science are inherent in ourselves 

 rather in an outside world. Our groups of perceptions 

 form for us reality, and the results of our reasoning on 

 these perceptions and the conceptions deduced from them 

 form our only genuine knowledge. Here only we are 

 able to reach truth — to discover similarity and to describe 

 sequence — and we must remorselessly criticise every step 

 we take beyond, if we would avoid the " muddy specula- 

 tion " which will ever arise when we attempt to extend 

 the field of knowledge by obscure definitions of natural 

 law. 



If it should seem to the reader that I have too 

 narrowly circumscribed, not the field of possible human 

 knowledge, but the meaning of the word knowledge 

 itself, he must remember the danger which arises when we 

 employ terms without concise meaning and clearly defined 

 limits. The right of science to deal with the beyond of 

 sense-impressions is not the subject of contest, for science 

 confessedly claims no such right. It is within the field of 

 knowledge as we have defined it, especially at points where 

 our knowledge is only in the making, that the right of 

 science has been questioned. It is easy to replace 

 ignorance by hypothesis, and because only the attain- 

 ment of real knowledge can in many cases demonstrate 

 the falseness of hypothesis, it has come about that many 

 worthy and otherwise excellent persons assert an hypo- 



