THE DOCTRINE OF EVOLUTION. 597 



The argument here set forth is my own. When I first used 

 it I had never met with it anywhere in books or conversation. 

 Whether it has since been employed by other writers I do not 

 know, for during the past fifteen years I have read very few 

 books on such subjects. At all events, it is an argument for 

 which I am ready to bear the full responsibility. Some doubt 

 has recently been expressed whether Mr. Spencer would admit 

 the force of this argument. It has been urged by Mr. S. H. 

 Wilder, in two able papers published in the New York Daily 

 Tribune, June 13 and July 4, 1890, that the use of this argument 

 marks a radical divergence on my part from' Mr. Spencer's own 

 position. It is true that in several passages of First Principles 

 there are statements which either imply or distinctly assert that 

 motion can be transformed into feeling and thought e. g., " Those 

 modes of the Unknowable which we call heat, light, chemical 

 affinity, etc., are alike transformable into each other, and into 

 those modes of the Unknowable which we distinguish as sensa- 

 tion, emotion, thought : these, in their turns, being directly or indi- 

 rectly retransformable into the original shapes " (First Principles, 

 second edition, 1867, p. 217) ; and again it is said "to be a necessary 

 deduction from the law of correlation, that what exists in conscious- 

 ness under the form of feeling is transformable into an equiva- 

 lent of mechanical motion," etc. (First Principles, second edition, 

 p. 558). Now, if this, as literally interpreted, be Mr. Spencer's 

 deliberate opinion, I entirely dissent from it. To speak of quan- 

 titative equivalence between a unit of feeling and a unit of mo- 

 tion seems to me to be talking nonsense to be combining terms 

 which severally possess a meaning into a phrase which has no 

 meaning. I am, therefore, inclined to think that the above sen- 

 tences, literally interpreted, do not really convey Mr. Spencer's 

 opinion. They appear manifestly inconsistent, moreover, with 

 other passages in which he has taken much more pains to ex- 

 plain his position (e. g., Principles of Psychology, pp. 158-161, 

 616-627). In the sentence of p. 558 of First Principles, Mr. Spen- 

 cer appears to me to mean that the nerve-action, which is the 

 objective concomitant of what is subjectively known as feeling, 

 is transformable into an equivalent of mechanical motion. When 

 he wrote that sentence perhaps he had not shaped the case quite so 

 distinctly in his own mind as he had a few years later, when he 

 made the more elaborate statements in the Psychology. Though 

 in these more elaborate statements he does not assert the doctrine 

 I have here maintained, yet they seem consistent with it. When 

 I was finishing the chapter on Matter and Spirit, in my room in 

 London one afternoon in February, 1874, Mr. Spencer came in, 

 and I read to him nearly the whole chapter, including my argu- 

 ment from correlation above mentioned. He expressed warm ap- 



