objective agencies; and, after asserting that these objective agencies are unknown and unknowable, positively lays down that they are not only agencies, but are also resistant and persistent. No man, it seems, knows the world beyond himself, yet Mr. Spencer, though a man, can tell what it is! But if he has a right to say that it is resistant and persistent, the man of science has a right to say that it is a world of bodies moving one another in space and time, and the man of religion has a right to speculate on the cause of this world of moving bodies. Hume, the consistent agnostic, left only a certain unknown, inexplicable something as the cause of our perceptions; a notion so imperfect that no sceptic will think it worth while to contend against it'. But the moment Mr. Spencer presumes to say that it is something resistant and persistent, agnosticism is at an end.

Mr. Spencer is an inconsistent thinker, because, without a previous analysis of scientific knowledge, he has attempted a synthetic philosophy after the model of the a priori school. Like Hegel, he drops many suggestive thoughts by the way; but his system is unsound. Nowadays, as Mr. Bramwell Booth remarks, these things are not entirely academic'. Crude philosophies are fast becoming popular errors. Oxford, Dec. 8.

MR. SPENCER AND HIS CRITICS

FROM The Times, DECEMBER 22, 1896. Silence gives consent. On December 11 you published a letter from me on the inconsistency of the whole basis of Mr. Spencer's philosophy. This morning there appears a letter from Mr. Spencer, dated December 16, excusing a similar inconsistency, pointed out by Mr. Bramwell Booth, by the plea that it is between different books published at

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different times, but taking no notice of the more fundamental inconsistency, which was pointed out by me, but is not capable of being thus excused, because it is published on one and the same system of synthetic philosophy at the present moment. By a curious coincidence, on the 15th, there appeared a letter from Mr. Collins, author of the Epitome of the Synthetic Philosophy, equally silent on this inconsistency, and even insinuating that I am too ignorant of evidence to be worthy of argument.

Mr. Collins proves this argumentum ad hominem by an ignoratio elenchi. He fastens on the end of my letter, where, after showing Mr. Spencer's inconsistency, I proceeded to account for it by saying that' without a previous analysis of scientific knowledge he has attempted a synthetic philosophy after the model of the a priori school'. In reply, Mr. Collins refers to some chapters in First Principles as analytic, and triumphantly exclaims that 'Professor Case says there is no analysis, and yet there it is!' But I do not say that there is no analysis in the synthetic philosophy; I say that there is no previous analysis of scientific knowledge before the synthetic philosophy. The analytic method would have begun by describing scientific discoveries, and proceeded to explain them by showing how sense and inference have produced science, in order to make this previous analysis a sure foundation of any subsequent synthesis. The synthetic philosophy, on the other hand, begins with hypotheses, not founded on analysis nor on any proof, and, as if they were mathematical principles, makes them premisses of synthetical deductions, ending in conclusions as hypothetical as the premisses, and so inadequate to the facts of science that Mr. Spencer soon becomes inconsistent in spite of himself. This must ever be the way with a method which is an anticipation, not an interpretation, of nature.

Force is the cardinal point of the synthetic philosophy. In the very first of the chapters, called by Mr. Collins analytic, but by Mr. Spencer himself ultimate scientific ideas', and in the very first paragraph on the subject of force, this synthetic philosopher begins with muscular force versus weight-e.g. in lifting a chair. Without any previous analysis, without any shadow of proof, he assumes that the force as known to us is an affection of consciousness'. Straightway, from this unproved hypothesis he synthetically deduces the equally hypothetical conclusion that we cannot attribute the force to a chair without endowing it with consciousness! It synthetically follows, no doubt, that the force of objective agencies is unknown and unknowable; if force as known to us is an affection of consciousness, then force as it exists out of our consciousness is not force as we know it. But this again hypothetical conclusion is so narrow and inadequate to the facts that Mr. Spencer becomes inconsistent. In the socalled analytic chapter on The Persistence of Force' he argues thus: Resistance and energy are the two modes of force both of which persist; but force which persists is not that force we are conscious of in our muscular efforts, for this does not persist; therefore force which persists is that absolute force of which we are indefinitely conscious as the necessary correlate of the force we know. In other words, the very objective agencies declared to be unknown and unknowable turn out to be persistent forces of resistance and energy. The synthetic philosophy in one breath says that force beyond consciousness is unknowable, and in the next breath that the persistence of this force is the ultimate universal truth.

The analytic method would simply reverse this argument. It would begin by describing the most certain principles of natural philosophy—namely, the Newtonian mechanical laws of motion and force,

impulsive and attractive, and the less certain biological and ethical theories of muscular and voluntary force. It would recognize resistance in objective force; it would proceed from the conservation of momentum to the conservation of energy. It would recognize that we must not endow a chair with consciousness, but it would recognize the resistant force of a chair. It would conclude that force as we know it is not always an affection of consciousness. It would end by trying to explain how, by sense and inference, science discovers the force of objective, as well as that of subjective, agencies. December 17.

FROM The Times, JANUARY 7, 1897.

Though I had intended to ask you to let me reply to Mr. Spencer's letter of January 1, nevertheless in presence of the very influentially signed memorial you publish this morning, proposing a national portrait of him, I feel that at so auspicious a moment it would be bad taste to say a word more than what may express a cordial approval of the proposal, with hearty congratulations to the philosopher who commands such public admiration.

January 6.

THE NEW PSYCHOLOGICAL HYPOTHESIS OF BRAIN WAVES

Sir William Crookes, K.C.B. (1832-1919), was a Fellow of the Royal Society and President of the Chemical Society.

FROM The Times, FEBRUARY 22, 1897.

As psychology has long been the paradise of paradox, it is not surprising that Professor Crookes has addressed to the Society for Psychical Research the question on which you wrote an article on February 1. 'Is it inconceivable', he asks, that intense thought concentrated towards a sensitive being with whom the thinker is in close sympathy may induce

a telepathic chain along which brain waves can go straight to their goal without loss of energy due to distance?'

In the abstract it sounds plausible to talk of a brain wave going, like a ball or any projectile, from one person to another. But the professor is taking advantage of the mere abstraction of wave motion. A wave of water appears to us to move onward and onward, but what really happens is nothing of the kind. The particles of water move up and down within a quite small circle, and those in one place make those in the next place move up and down, and so on in succession, without any corresponding onward motion except in appearance. That this is so is proved by putting a stick or still better oneself into the water, and finding that one is moved up and down without being hurried along with the apparent wave. The motion of oneself is not different from the general motion of the parts of the water, and in fact is a part of it. The parts of the water, therefore, do not really move onward in the apparent wave; and in a river, when the wind is blowing up-stream, they are really moving down the stream while the wave appears to move upwards. The onward motion of a wave, in short, is a mere appearance, and a useful abstraction, not, however, to be substituted for what really happens. This is true not only of waves of water, but also of the socalled propagation of all undulatory motion, whether in the direction of propagation as in sound, or transversely to that direction as in light. The very point of the undulatory theory of light is that nothing is emitted and nothing goes from the sun to the earth, but that each portion of the ether is successively agitated by its predecessor, and each portion moves in a very small circle, and yet a tremor appears to pass through the whole in a manner roughly analogous to the shaking of a jelly.