it is possible for aerial vibrations to generate the sensation we call sound, for the force liberated by chemical changes in the brain to give rise to emotion-these are mysteries which it is impossible to fathom. But they are not profounder mysteries than the transformation of the physical forces into each other.-First Principles, 1st ed., p. 280.

This passage proceeds on the view mentioned. It takes the correlation of physical energies as the type of the process. But when one form of energy passes into a new form, it no longer exists in the old one. We should expect, then, that when physical energy passes into thought it no longer exists as physical energy. On this theory there may be a passing back and forth of physical energy between the nervous and the mental realm.

But in spite of this and many similar passages, Mr. Spencer and the evolutionists in general do not accept this view. It involves a serious break of physical continuity, and implies that the laws of motion do not determine all physical changes. The nervous state at any moment is determined not merely by the antecedent nervous state, but by that plus an irruption from the mental realm. Besides, the notion that physical energy should suddenly lay aside its distinctive character and become a thought, borders on the grotesque and the irredeemably absurd. These considerations have led to the view, now largely adopted by evolutionists, that neurosis does not pass into psychosis, but is attended by it. According to Prof. Clifford, the physical series goes along by itself, and the mental series goes along by itself. The favorite statement with Mr. Spencer is that the physical and the mental series "are the subjective and objective faces of the same thing." Prof. Bain also uses similar language, affirming a mental fact to be double-faced, being on one side a mental state, and on the other side a nervous change. Unfortunately this language is not so clear as could be desired. Both mind and matter appear in Mr. Spencer's formula as "faces;" but the relation of these "faces" is left undetermined. Are they mutually independent, so that the two faces go on by themselves? or does the mental face depend upon the physical face? Mr. Spencer thinks to escape materialism by this doublefaced theory; but in vain. He points out at great length the impossibility of assimilating the mental to the physical series. One passage ("Principles of Psychology," vol. i, pp. 157–162) has become classic among the Spencerians. "That a unit of feel

ing has nothing in common with a unit of motion becomes more than ever manifest when we bring the two into juxtaposition." "Nevertheless, it may be as well to say here, once for all, that if we were compelled to choose between the alternatives of translating mental phenomena into physical phenomena, or translating physical phenomena into mental phenomena, the latter alternative would seem the more acceptable of the two." This paragraph is often appealed to by the Spencerians as conclusively disproving the charge of materialism, and even as overthrowing materialism itself. It does not agree very well with the following utterance, also meant to be decisive: "See, then, our predicament. We can think of matter only in terms of mind. We can think of mind only in terms of matter."Principles of Psychology, vol. i, p. 627. Mr. Spencer adds that we can get values of y only in terms of x, and conversely. We can hardly believe that he was betrayed into the latter statement by the alliteration and the antithesis; and yet there seems to be no better ground for it. Let one try to think of motion in terms of love, or of love in terms of motion, and the absurdity becomes apparent. Moreover, the previous quotation is a distinct refutation of the latter; and as the statements there made were made " once for all," we must regard them as Mr. Spencer's final view. Yet, antimaterialistic as it seems, the affirmation is merely that mental phenomena cannot be conceived in terms of any thing else; but it does not deny that they may be, and are, the product of something else. Thought and feeling as mental states are incommensurable with matter and motion; but this is an irrelevant commonplace so long as it is allowed that they result from the redistribution of matter and motion. For the question is not whether they can be joined in a common thought, but whether thought depends on matter and motion. What was said before about the "opposite faces" applies equally to the incommensurable series. The physical series is viewed as the independent fact, and the mental series as only a concomitant product. It is this fact which justifies common sense in ranking Mr. Spencer with the materialists.

Mr. Spencer's working theory is best expressed in the following quotation: "As shown in the earlier part of this work, an idea is the psychical side of what on its physical side is an involved set of molecular changes propagated through an in

volved set of nervous plexuses. That which makes possible the idea is the pre-existence of these plexuses so organized that a wave of molecular motion diffused through them will produce, as its psychical correlative, the components of the conception in due order and degree. This idea lasts while the waves of molecular motion last-ceasing when they cease; but that which remains is the set of plexuses. These constitute the potentiality of the idea, and make possible future ideas like it.”—Principles of Psychology, vol. ii, p. 484; see also vol. i, pp. 270,406.

In this passage and in many others the independence of the physical fact, "face," or series, is plainly affirmed. With equal clearness the dependent and transitory nature of the mental fact, "face," or series, is affirmed. Both may be "faces," and incommensurable, but none the less, the physical "face," compared with the mental "face," is independent and abiding. The bewildering statements about double-faced somewhats and opposite manifestations of the unknowable, must not be allowed to obscure this fact.

But even yet we have no clear statement of the relation of neurosis and psychosis. The doctrine is that psychosis is the concomitant of neurosis, but the doctrine is also that the energy of neurosis never passes into an energy of psychosis. The physical series goes along by itself with unbroken continuity. If, then, we could accurately observe nervous movements, we should find every nervous antecedent exhausted in its nervous consequent, and we should nowhere get any hint of the mental series supposed to be going on at the same time. But this view calls up the gravest difficulties. The mental series in this case is not caused by the physical series, but attends it. If, then, the mental series have any energy, or if it have any laws peculiar to, and founded in itself, we must seek its cause outside of the physical series. And if the mental series goes along by itself, and the physical series goes along by itself, then we have no means of accounting for their harmony or even for their connection. The difficulty is the old one with which the students of Spinoza are familiar. He viewed being, as extended, as going along by itself, and being, as thought, as going along by itself. Nothing happens in the physical world which is not fully accounted for by its physical antecedents, and nothing happens in the mental world which is not fully ac

counted for by the mental antecedents. Between the two there is no interaction. But in that case, how account for their parallelism and co-existence? Neither accounts for the other, and we seem able to save knowledge only by a theory of preestablished harmony. We gain no relief by calling them opposite faces of the same thing, for then in logic we should make the opposite faces inseparable, so that mentality should be as universal as materiality; and even this expensive solution would not help us. For neither face, as face, explains or affects the other. The opposite faces still go along by themselves in mutual indifference. Nor would it avail to take the extreme positions of identifying the opposite faces, and say that all being is at once material and ideal according to our standpoint; for being, as thought, would be determined by the laws and norms of logic, while being, as material, would be determined by the laws of motion. The two views would not unite. If now we hold to physical continuity, we must either allow that the mental series is independent and has its cause and ground outside of the physical realm, or we must affirm that the mental series is merely a powerless attendant upon the physical processes, and is determined by them in every respect. Psychosis is merely the shadow of neurosis, and, like all shadows, is unsubstantial and powerless. The shadows come and go as the nervous states change, but they have no bond of connection among themselves. The bond which binds them is the nervous mechanism; but this bond appears among the shadows as a rational connection. This notion is admirably expressed in the following passages from Professor Huxley's lecture "On the Hypothesis that Animals are Automata: "

The consciousness of brutes would appear to be related to the mechanism of their body, simply as a collateral product of its working, and to be as completely without any power of modifying that working as the steam whistle which accompanies the work of a locomotive engine is without influence upon its machinery. Their volition, if they have any, is an emotion indicative of physical changes, not a cause of such changes. *

* *

*

It is quite true that to the best of my judgment the argumentation which applies to brutes holds equally good of men, and, therefore, that all states of consciousness in us, as in them, are immediately caused by molecular changes of the brain substance. It seems to me that in men, as in brutes, there is no proof that any state of consciousness is the cause of any change in the moFOURTH SERIES, VOL. XXXII.-29

tion of the organism. If these positions are well based, it follows that our mental conditions are simply the symbols in consciousness of the changes which take place automatically in the organism, and that, to take an extreme illustration, the feeling we call volition is not the cause of a voluntary act, but the symbol of that state of brain which is the immediate cause of that act.

Similarly Mr. Spencer, in the division entitled, "Special Synthesis," ("Principles of Pychology, vol. i,") teaches that instinct, memory, reason, feeling, and will, are but subjective symbols of nervous processes, which processes go on by themselves. Reason is explained as follows:

For though when the confusion of a complex impression with some allied one causes a confusion among the nascent motor excitations, there is entailed a certain hesitation, and though this hesitation continues as long as those nascent motor excitations or ideas of the correlative actions go on superseding one another; yet, ultimately, some one set of motor excitations will prevail over the rest. As the groups of antagonistic tendencies aroused will scarcely ever be exactly balanced, the strongest group will at length pass into action, and as this sequence will usually be the one that has recurred oftenest in experience, the action will on the average of cases be the one best adapted to the circumstances. But an action thus produced is nothing else than a rational action.-Vol. i, p. 455.

On page 496 he describes volition in the same way as a conflict of nascent motor excitations ending at last in the victory of the strongest. It is not ideas as ideas which conflict, but ideas as nascent motor excitations, that is, as "nascent excitations of the nerves concerned." The premises do not determine the conclusion, and reason does not determiue the will; but underlying all is a mechanism of nervous states subject only to the laws of physical motion, whose resultant appears in consciousness as reasoning and volition. In the strictest sense of the phrase, the physical series goes along by itself without interference from the mental side. Doubtless many passages could be found in Mr. Spencer's works which conflict with this view, but a "mazy mingling of inconsistent views" is a prominent feature of his writings. We are sure that no competent and candid critic can interpret his system so far as it is a system, other than we have done. Neurosis is the independent fact, and psychosis is its unsubstantial shadow.

We have made this lengthy preamble for the sake of show