lOO THE GRAMMAR OF SCIENCE 



that our intellect has been keen enough to reach a formula 

 extending to the whole range of facts it professes to 

 resume, is the actual comparison of the results of the 

 formula with the facts themselves — that is, historical 

 observation or physical experiment. This test is all that 

 marks the division between scientific hypothesis and 

 scientific law, and the scientific law itself must, with every 

 increase of our perceptive powers, return to the position 

 of hypothesis and be anew put to the test of experience. 

 Yet what philosophic system, what fantasy of the meta- 

 physical mind in the region of the supersensuous has 

 stood like Newton's formula of gravitation without the 

 least change, the least variation in its statement, for more 

 than two hundred years ? Assuredly none ; they have 

 all shifted their ground with every advance of man's 

 positive knowledge. They have not stood the test of 

 experience ; they are phantasms, not truth ; for, as Sir 

 John Herschel has said : — 



" The grand, and indeed only, character of truth is its 

 capability of enduring the test of universal experience, 

 and coming unchanged out of every possible form of fair 

 discussion." 



^11 . — TJie Universality of Scientific Law 



The universality, the absolute character, which we 

 attribute to scientific law is really relative to the human 

 mind. It is conditioned : — 



1. By the perceptive faculty. The outside world, the 

 world of phenomena, must be practically the same for all 

 normal human beings. 



2. By the reflective faculty. The processes of asso- 

 ciation and logical inference, and the inner world of stored 

 impresses and conceptions must be practically the same 

 for all normal human beings. 



Now, when we classify a number of things together 

 and give them the same name, we can only mean to 

 signify that they closely resemble each other in structure 

 and action. Hence when we speak of Jminan beings we 



