14 PHYSICAL SCIENCE 



apprehend the results of experiment through our 

 senses alone. Though, for instance, the galvano- 

 meter seems at first to supply us with a new- 

 electrical sense, on further thought we see that 

 it merely translates the unknown into a language 

 our sense of sight can appreciate, as a spot of 

 light moves over a scale. It is possible that 

 Philosophy may take into account knowledge 

 which reaches us by means other than the 

 senses. Intuitions, fundamental assumptions, 

 mental processes generally, doubtless have an 

 external aspect, and may be studied by the 

 science of Psychophysics, but they may have 

 also another aspect in their internal relations to 

 consciousness. Here they can be examined by 

 Psychology. But we can only study Nature 

 through our senses — that is, we can only study 

 the model of Nature that our senses enable our 

 minds to construct ; we cannot decide whether 

 that model, consistent though it be, represents 

 truly the real structure of Nature ; whether, 

 indeed, there be any Nature as an ultimate 

 reality behind its phenomena. 



In emphasising the essential distinction 

 between Natural Science and Metaphysics, we 

 must not suppose that the results of Natural 

 Science have no metaphysical import. The 

 possibility of putting together a consistent mental 

 model of phenomena is a valid metaphysical 

 argument in favour of the view that a consistent 

 reality underlies those phenomena, and that the 

 reality is represented with more or less faithful- 

 ness by the mental picture we have pieced 

 together. Such an argument must carry great 

 weight, and may, perhaps, be considered con- 



