484 SCIENTIFIC THOUGHT. 



self made a very important application of it, by bringing 

 it into connection with Young's colour theory. But 

 before I refer to this, it will be well to note the different 

 lines of research which were opened out by Miiller's 

 formula, and how they have led in many ways to very 

 fruitful expansion of natural knowledge. In this respect 

 it is indeed permissible to compare Miiller's formula with 

 that of gravitation, which, as we saw above, through 

 the different ideas which it introduced, helped to guide 

 research for fully a century. Miiller in the original 

 statement of his views had made use of the term " specific 

 energy," and had applied this term to the process or 

 sense of sight: he spoke of the seeing substance or 

 apparatus of sight. Now this apparatus is a complicated 

 one, consisting mainly of three parts the external or 



edition of his great work on Physi- Montgomery in the fifth volume of 

 ological Psychology in 1872. See 'Mind' (1880): " According to the 

 the note on p. 332, vol. L, of the doctrine of functional indifference, 

 4th German edition (1893). Wundt the various qualities i.e., our well- 

 says (p. 331) : " Historically, the ' known sensations are merely due 

 doctrine . . . is to be traced to the to differences in the stimulating 

 fact that the philosophical founda- rhythm, to differences, therefore, of 

 tion of modern science, and especi- motion communicated from outside 

 ally of the science of sensation, rests to the chemically uniform nerve- 

 on Kant. In fact, that doctrine substance, and the whole complex 

 is nothing else than a physiological make-up of our consciousness is, 

 reflexion of Kant's attempt to find consequently, thought to result 

 the conditions of knowledge which \ from the coexistence and subse- 

 are given a, priori, or, what was quent combination of such stim- 

 mostly considered to be the same, ulated motions. According to the 

 subjectively. This is very evident doctrine of specific energies, the 

 in the case of the foremost repre- varieties of sensation are due to pre- 

 sentative of that doctrine viz., existing differences in the sub- 

 Johannes Miiller." In opposition to stratum in which they respectively 

 Miiller and his school, Lewes and I arise, and all their manifold combin- 

 Wundt put forward a view which ! ations to higher products are be- 

 has been termed the doctrine of lieved to be realised in materially 

 indifference of the function of the higher i.e., specifically pre - en- 

 iiervous elements. The difference dowed ranges of nervous sub- 

 bet ween the two views is very clearly stratum" (p. 4). 

 stated in an excellent paper by E. 



