12 THE UNFATHOMED UNIVERSE 



dividual experience (a view which would lead us near the 

 impasse of solipsism), for they are verifiable by all normally 

 constituted minds, and that they must have a close corre- 

 spondence with the actualities of Nature since the predictions 

 based on them are fulfilled. We continually risk our lives 

 on the closeness of this correspondence. That we are not 

 betrayed proves, not that the concepts or intellectual count- 

 ers used in representation are like the real things, or are 

 even the only usable concepts, but that the uniformities 

 which the concepts are used to detect and to represent are 

 real. 



Speaking of the electrical theory of matter, the late Prof. 

 J. H. Poynting said : " The chief value of such hypothesis 

 lies, not in its objective truth, but in its success in account- 

 ing for, in co-ordinating, what we actually observe, and in 

 predicting results which are afterwards verified. It is to 

 be regarded as a ' working model ' which gives the same 

 results as the actual atom, though, it may be, by quite 

 different machinery." While adhering to this view, let 

 us, however, safeguard it by recognising that the validity 

 of the working model depends on its verifiability, and on 

 its correspondence with actualities. As Hertz said, the 

 quality of scientific symbols is such that their intellectually 

 necessary consequences correspond to occurrences. For 

 certain purposes the view that the sun goes round the earth 

 is just as effective as the conclusion that the earth goes 

 round the sun. We can rise at dawn with equal punctuality 

 on either hypothesis. But beyond a short radius the former 

 will lead us hopelessly wrong, while the latter never will. 



(d) Fourthly, it is interesting to notice that Bacon did 

 not include historia naturalis in his encyclopaedia of the 

 sciences, probably because it remained too concretely de- 



