There must be scores and hundreds of educated minds to whom the readiest illustration of the "Unknowable" would be Mr. Herbert Spencer's metaphysical conclusions. Mr. Guthrie's estimate of the reasoning on which they rest is thus plaintively stated:— "The book is like the process of evolution itself; we never know where we are; we seem to slip from one thing into another so easily, that in the transmutation and connection of words we often have a difficulty in making out our position." He criticizes in no hostile spirit, he tells us, but simply proposes a logical examination of the new theory. Philosophy, according to Mr. Spencer, is completely unified knowledge, as distinguished from knowledge and science. And the problem of philosophy is to state an intelligible formula which, by its application to the Homogenous, will explain, and enable us to construct ideally, all the changes of the universe. The formula itself is this:— "Evolution is an integration of matter and concomitant dissipation of motion, during which the matter passes from an indefinite, incoherent homogeneity, to a definite, coherent heterogeneity, and during which the retained motion undergoes a parallel transformation." To this, Mr. Guthrie objects its insufficiency, inasmuch as its two factors, matter and motion, do not explain the facts of life and mind. He then attempts to introduce the term "Force," but finds the amended formula, if sufficient, no longer intelligible. Upon which he not unnaturally concludes that no such formula as shall serve the purpose is possible; and with it the value of Mr. Spencer's attempted generalisations falls to the ground.
—The Bookseller [1880]