18 



SCIENCE. 



[N. S. Vol. XIV. No. 340. 



of ignorance, the situation is not altogether 

 hopeless. Thus, while it is true that scien- 

 tists are likely to insist, even in the face of 

 the principle of thought preserving the 

 unity of an indivisible universe in all the 

 varied studies and conclusions of science, 

 that physics is nevertheless only physics 

 and chemistry only chemistry and biology 

 only biology and psychology only psychol- 

 ogy, and while also my illustrations must 

 all come from the field of their special 

 sciences and may therefore only set them 

 more firmly in the willful blindness of 

 specialism, still the principle itself, the 

 principle of a conserving thought, is a dis- 

 turbing influence which they cannot escape, 

 and then besides I am for the moment 

 forgetting and asking them to forget a 

 very important fact of scientific study to- 

 day. In these times the running together, 

 or merging, of different sciences, as if 

 through something of the nature of a chemi- 

 cal reaction, is a very familiar phenomenon, 

 and it has been taking place with such per- 

 sistence and confidence as actually to sug- 

 gest a natural affinity, each of the sciences 

 involved having the rich experience of dis- 

 covering itself in the others. This fact, 

 then, must make illustration at least less 

 difficult, since in a way that is certain to 

 appeal to science as no mere theory ever 

 can, it proves or goes far towards proving 

 what is to be illustrated. Moreover, specific 

 illustration is hardly necessary in the sphere 

 of the physical sciences or again in that of 

 the social or of the psychological sciences, 

 for within each one of these groups the 

 affinity but just now referred to has been 

 clearly exemplified, as in the interesting 

 case of physics, chemistry and mathe- 

 matics. Illustration, then, is needed only 

 for the physical in relation to the so- 

 cial and psychological, and to this I now 

 turn. 



In articles already published under the 

 titles ' Epistemology and Physical Science 



— A Fatal Parallelism,'* and 'Physical 

 Psychology,' f I have undertaken to show, 

 and I believe I have at least made a begin- 

 ning of showing, that the dualism of mind 

 and matter, which separates the physical 

 and psychical sciences, is logically repro- 

 duced, as if by a sort of projection, within 

 the special spheres of each. Physical psy- 

 chology is ^ concerned with the substitutes 

 or indirections for mind [for the sort of 

 unity, intensive instead of extensive or 

 qualitative instead of quantitative or vital 

 and spiritual instead of physical, which is 

 always associated with mind] that appear 

 in all the so-called physical sciences,' and 

 corresponding to physical psychology there 

 is a psychological or epistemological physics, 

 in its turn concerned with the substitutes 

 for quantity and matter that are present in 

 all the psychical sciences. The sensuous 

 self, for example, with the atomism that it 

 has always involved psychology and epis- 

 temology in, is only as if a projection of the 

 physical on the psychical. Sensationalism, 

 as we all know, has ever been closely asso- 

 ciated in history with materialism. And, 

 on the other side, in conservation, J in plen- 

 itude, in motion as relative, that is to say, 

 as always under a principle of uniformity 

 or constancy, and also as inclining to some- 

 thing like vibration or rotation, in which it 

 is an expression of rest as well as motion, 

 and finally, not to continue what might be 

 a long catalogue, in the infinity of space 

 and time or— as the same thing — of quan- 



* See PhilosopMcal Eevietv, July, 1898. 



t See Psychological Revieiv, March, 1900. 



X The case of conservation, in addition to what is to 

 be said here and to what has been said in the two 

 articles referred to above, may be put in this way. 

 Thus is not the 'constant quantity,' not a mere 

 quantity, but a ratio ? As a ratio, even if finite, it is, 

 like all ratios, more than merely quantitative, its 

 constancy testifying, not to mere quantitative unity, 

 but to a unity that quite transcends any purely quan- 

 titative differences. As ratios all quantities are both 

 finite and infinite. 



