It is one of the difficulties of Spencer's system that even when he is using physical concepts he is thinking of these not merely as symbols by which to formulate the routine of our sense-experience, but as symbols of the reality behind matter and motion of which we do not know anything. He works with the concept which he calls "the persistence of force," and when the reader is feeling its inadequacy to meet the situation, he is bluffed by the reminder—"By persistence of force we really mean the persistence of some Power which transcends our knowledge and conception": "Asserting the persistence of Force is but another mode of asserting an Unconditioned Reality without beginning or end."
(3) When an investigator in giving an account of a process insists on using higher categories than the sequences appear to require, he is guilty of "a transcendentalism," e.g., if he says that an instinctive action is rational, or that digestion is a psychical process. Similarly, when an investigator in giving an account of a process insists on using lower categories than the sequences appear to require, he is guilty of "a materialism," e.g., if he says that a rational act is simply a higher reflex, or that digestion is simply a chemical reaction. Therefore, although Spencer was not a materialist, we think that he was guilty of gross "materialisms," of attempting to give a false simplicity to the facts, e.g., in his attempt to trace the evolution of mind in terms of the evolution of the nervous system, and in his universal evolution-formula which is wholly in terms of Matter and Motion.
(4) By keeping throughout to mechanical categories, Spencer gives a semblance of simplicity and precision to his evolutionism, and his skill is such that the unwary reader is led gently on from orders of facts where mechanical categories (if not Spencer's) do certainly suffice, to other orders of facts—in immaterial evolution—where they seem strangely irrelevant. But if the reader, having his suspicions aroused by sundry jolts and jars in the onward sweep of the chariot of First Principles, begins to inquire into the reality of the apparent mechanical precision, he is likely to be disillusioned. Thus, at an early stage, he may discover that Spencer uses the word "force" without special definition in at least five senses,[11] which is not reassuring.
[11] See Karl Pearson. The Grammar of Science, p. 329.
As we have no expertness in these matters, we would submit the verdict of a recognised authority, Prof. Karl Pearson. One of Spencer's principles is "the redistribution of force," which he states in the following words:—
"A decreasing quantity of motion, sensible or insensible, always has for its concomitant an increasing aggregation of matter, and conversely an increasing quantity of motion, sensible or insensible, has for its concomitant a decreasing aggregation of matter."
In regard to this Prof. Pearson remarks: "This principle has, so far as I am aware, no real foundation in physics... it seems, so far as I can grasp it at all, to flatly contradict the modern principle of the conservation of energy"... the keystone of Spencer's system.
(5) What has taken place since Spencer stereotyped his First Principles seems to us to have rendered it almost useless to attempt a detailed criticism of his scheme of evolution—wonderful and stimulating as it was and is. He spoke of his delight in "intellectual hunting," and a great huntsman he certainly was, but the venue has changed since his day. He did not fully nor always rightly utilise the chemistry and physics of his time, and we have now to deal with a new chemistry and a new physics.
Mr J. B. Crozier speaks of Spencer as "of all thinkers ancient or modern the one whose power of analysing, decomposing, and combining the complex web of Matter, Motion, and Force is the most incontestable and assured." He describes Spencer's system as "No mere logical castle built of air and definitions, and assuming in its premises, like the systems of the metaphysicians, the very difficulties to be explained, but a great granite pile sunk deep in the bed-rock of the world, each stone a scientific truth, and all so compacted and dove-tailed together that it was difficult to find anywhere a logical flaw among their seams."
This is one view, but another will be found in Prof. James Ward's Gifford Lectures on "Naturalism and Agnosticism," in Mr Malcolm Guthrie's three volumes of criticism, and in several luminous papers by Principal James Iverach.