AND ITS SELF-COKSERVATION. 57 



many of the definitions above, would be entitled to 

 claim the name of matter, even when it is not set in 

 rotation." 



After thus indicating that the theory which his former 

 associate had developed, with a view to explaining the 

 constitution of matter, has the " curious peculiarity " of 

 assuming the thing it was proposed to prove, Professor 

 Tait adds : " But as we do not know, and are probably 

 incapable of discovering, what matter is, what we want at 

 present is merely a definition which, while not at least 

 obviously incorrect, shall for the time serve as a working 

 hypothesis." 



He therefore chooses to "define, for the moment, as 

 follows : 



''Matter is whatever can occupy space;" and this for 

 the following reason : 



"Experience has proved that it is from this side that 

 the average student can most easily approach the sub- 

 ject." * * * 



The point of view from which we have set out in the 

 present essay, then, is not one that the strictly scientific 

 mind would call an " obviously incorrect " one. And it is 

 reassuring to have such confirmation from one who has 

 gained the right to speak as one having authority, and not 

 as the scribes, or "paper scientists." 



Amid such uncertainties, too, it would seem to be 

 not wholly unwarrantable for even the "mere meta- 

 physician" to throw in his conjecture also, though, 

 from the expressions Professor Tait uses, it can hardly 

 be expected that such conjectures will be estimated 

 above the merest infinitesimals by the mere ( ?) mathe- 

 matician. 



