A DEFENCE OF PRAGMATISM 353 



It is evident that the term applies itself conveniently to a number of 

 tendencies that hitherto have lacked a collective name, and that it has 

 ' come to stay.' 



To take in the importance of Peirce's principle, one must get 

 accustomed to applying it to concrete cases. I found a few years ago 

 that Ostwald, the illustrious Leipzig chemist, had been making perfectly 

 distinct use of the principle of pragmatism in his lectures on the 

 philosophy of science, though he had not called it by that name. 



" All realities influence our practise," he wrote me, " and that in- 

 fluence is their meaning for us. I am accustomed to put questions to 

 my classes in this way: In what respects would the world be different 

 if this alternative or that were true ? If I can find nothing that would 

 become different, then the alternative has no sense." 



That is, the rival views mean practically the same thing, and 

 meaning, other than practical, there is for us none. Ostwald in a 

 published lecture gives this example of what he means. Chemists have 

 long wrangled over the inner constitution of certain bodies called 

 ' tautomerous.' Their properties seemed equally consistent with the 

 notion that an instable hydrogen atom oscillates inside of them, or that 

 they are instable mixtures of two bodies. Controversy raged ; but never 

 was decided. " It would never have begun," says Ostwald, " if the 

 combatants had asked themselves what particular experimental fact 

 could have been made different by one or the other view being correct. 

 For it would then have appeared that no difference of fact could 

 possibly ensue; and the quarrel was as unreal as if, theorizing in old 

 times about the raising of dough by yeast, one party should have in- 

 voked a ' brownie,' while another insisted on a ' fairy ' as the true cause 

 of the phenomenon." 3 



It is astonishing to see how many philosophical disputes collapse 

 into insignificance the moment you subject them to this simple test of 

 tracing a concrete consequence. There can be no difference anywhere 

 that doesn't make a difference elsewhere — no difference in abstract 

 truth that doesn't express itself in a difference in concrete fact and in 

 conduct consequent upon that fact, imposed on somebody, somehow, 

 somewhere and somewhen. The whole function of philosophy ought 

 to be to find out what definite difference it will make to you and me, 

 at definite instants of our life, if this world-formula or that world- 

 formula be the true one. 



8 ' Theorie und Praxis,' Zeitsch. des Oesterreichischen Ingenieur u. Archi- 

 tecten-Vereines, 1905, Nr. 4 u. 6. I find a still more radical pragmatism than 

 Ostwald's in an address by Professor W. S. Franklin : " I think that the sick- 

 liest notion of physics, even if a student gets it, is that it is ' the science of 

 masses, molecules and the ether.' And I think that the healthiest notion, even 

 if a student does not wholly get it, is that physics is the science of the ways of 

 taking hold of bodies and pushing them! " (Soience, January 2, 1903.) 



vol. lxx. — 22. 



