My dear Father.

I return you Guthrie which I have been very much interested in.² He certainly shews that Spencer makes far too vast a claim as to what his formula includes, and convicts him of absolute contradiction about the mutability of the homogeneous.³

The book as a whole seems to me to shew that as long as Spencer is discussing inorganic evolution the word “force” & “forces” are confusing and unnecessary according to his formula; but as soon as he comes to organic life there are signs that he either consciously or unconsciously feels that “matter in motion” is insufficient, and that something further included in the word “force” is needed; as when he says “the reader must be reminded when applying the formula to life & society, in what sense the interpretations must be understood namely that they are to be interpreted in “terms of force”” without its being explained anywhere what the terms are⁴

And Guthrie I think shows that any formula to include organism &c must probably include force (apart from matter and motion) as represented by an original consciousness of the ultimate units of matter, or consciousness rising at a later period; which last idea seems to me less logical than the first.⁵

I cannot conceive how Spencer can make the evolution of language society industry actually the integration of matter & dissipation of motion; though the evolution of language may be very similar, I think the book brings out in spite of its criticism the wonderful parallelism that does exist in evolution of the world, and that if Spencer’s is only a “description” and not an “explanation”, anyhow evolution is the process and some one else has to frame a better formula.⁶ I shall like to see what Moulton says about it, if he writes to you.⁷

The part about the unknowable seems to show that Spencer juggles with the “relative” & the “non relative”, but I am not up to it.⁸

I hope your Romanes visit went off without much labour.⁹

Thank you for the label writing description¹⁰

Your affect son | W E. Darwin

I think this American pen after all is extremely pleasant to write with.