logical standpoint. If I can know that minds and brains are parallel, my mind cannot wholly be shut up to the psychic concomitants of brain-changes. If all my knowledge really is included in the M'I' of the formula, the rest of the formula is non-existent for me, and I am not a parallelist.

To be a parallelist, such a parallelist as Clifford was while he was building up the argument, one must be naïve; one must shut the mind up to its sensations and ideas, and at the same time let it know an external world beyond its sensations and ideas, a world of material things to which sensations and ideas are parallel. The inconsistency is glaring, and it is little wonder that the parallelist tries to remove it by becoming a metaphysician. This is what Clifford has done. As a metaphysician he has denied the material world of candlesticks and brains to be external at all. But without something external he cannot get on, and he, hence, offers us a new externality of a different sort. He quite wrecks his parallelistic formula, it is true; but the fact that he does so is not at once evident, and he may still account himself a parallelist — an enlightened parallelist. The fact is that he occupies two positions at once, that of the plain man, who is a dualist, and that of the subjective idealist.

We have seen what comes of adhering half-heartedly to the position of the plain man, but there is danger that we may see it and straightway forget it. Hence, I shall make no apology for discussing in the following chapter The Metaphysics of the "Telephone Exchange." It ought to be of some interest both to the metaphysician and to the man who is accustomed to shake his head over metaphysicians.

CHAPTER XXII

THE METAPHYSICS OF THE "TELEPHONE EXCHANGE"

WE are told by Professor Karl Pearson that the material of science is coextensive with the whole life, physical and mental, of the universe. The field of science is coextensive with knowledge. "If there are facts, and sequences to be observed among those facts, then we have all the requisites of scientific classification and knowledge. If there are no facts, or no sequences to be observed among them, then the possibility of all knowledge disappears." There are many branches of science, and some are better established than others, yet in all it seems possible for men to come to something like a practical agreement as to fundamental principles.

"The case is quite different with metaphysics and those other supposed branches of human knowledge which claim exemption from scientific control. Either they are based on an accurate classification of facts, or they are not. But if their classification of facts were accurate, the application of the scientific method ought to lead their professors to a practically identical system. Now one of the idiosyncracies of metaphysicians lies in this: that each metaphysician has his own system, which, to a large extent, excludes that of his predecessors and colleagues. Hence we must conclude that metaphysics are built either on air or on quicksands - either they start from no foundation in facts at all, or the superstructure has been raised before a basis has been found in the accurate classification of facts. I want to lay special stress on this point. There is no short cut to truth, no way to gain a knowledge of the universe except through the gateway of scientific method. The hard and stony path of classifying facts and reasoning upon them is the only way to ascertain truth. It is the reason and not the imagination which must ultimately be appealed to. The poet may give us, in sublime language, an account of the origin and purpose of the universe, but in the end it will not satisfy our æsthetic judgment, our idea of harmony and beauty, like the

few facts which the scientist may venture to tell us in the same field. The one will agree with all our experiences past and present, the other is sure, sooner or later, to contradict our observation, because it propounds a dogma, where we are as yet far from knowing the whole truth. Our æsthetic judgment demands harmony between the representation and the represented, and in this sense science is often more artistic than modern art."1

In a foot-note Professor Pearson tells us that it is perhaps impossible satisfactorily to define the metaphysician, but that the meaning he attaches to the term will become clearer later in his book. The above extract, taken alone, seems to make the accusation against him a general shiftlessness of mind, proceeding from a poetic indifference to scientific method. The author regards him as a dangerous member of the community, because it is not recognized that he is merely a poet, and he is apt to be taken seriously. He is a "Portuguese of the Intellect," who endeavors to establish a right to the foreshore of our present ignorance, and may hinder the settlement in due time of vast and yet unknown continents of thought. This science should prevent. But as we read on we discover that the charge against this dark character is a much more specific one. The real head and front of his offending is not so much that he recklessly anticipates the cautious generalizations of science, as that he lays claim to a realm beyond the sphere of science altogether.

From the material provided by the senses, either directly or in the form of stored sense-impressions, science draws conceptions. These are products of the reflective faculty, and they exist in the imagination. It is legitimate to form conceptions of things not directly verifiable by the senses, but so long as they are not thus verifiable, we are not justified in asserting that they have objective reality. Atoms and molecules are such conceptions. In a sense they are supersensuous, for no man has become directly conscious of them as sense-impressions, and perhaps no man ever will; but this means only that they are mental conceptions which assist us in classifying phenomena, i.e. sense-impressions. Science has, hence, to do only with sense-impressions and with ideal constructs which are useful in helping us to arrange the same. Only what is directly given as sense-impression is actual. Thus the supersensuous of science is but a construct in the imagination; it is made up of 2 p. 25.

1 "The Grammar of Science," 2d ed. London, 1900, pp. 16, 17.

remembered sense-impressions, and it has no being in an extra mental world. "On the other hand, the metaphysician asserts an existence for the supersensuous which is unconditioned by the perceptive or reflective faculties in man. His supersensuous is at once incapable of being a sense-impression, and yet has a real existence apart from the imagination of men. It is needless to say that such an existence involves an unproven and undemonstrable dogma." 1

Since the metaphysician holds to the supersensuous in this sense of the word, his doctrine is "pseudo-science."2 He fills the "beyond" of sense-impression with "phantasms." It is as an "unconscious metaphysician" that Professor Tate, the author of "The Properties of Matter," makes of matter a something beyond the sphere of perception. As a something in the "beyond" of sense-impression, matter is a metaphysical entity meaningless for science. The statements of physicists and common-sense philosophers with regard to the nature of matter "are one and all metaphysical that is, they attempt to describe something beyond sense-impression, beyond perception, and appear, therefore, at best as dogmas, at worst as inconsistencies. If we confine ourselves to the field of logical inference, we see in the phenominal universe not matter in motion, but sense-impressions and changes of senseimpressions, coexistence and sequence, correlation and routine."6 We must carefully distinguish "conceptual matter from any metaphysical ideas of matter as the substratum of sense-impression.”7 Minds which cannot wholly repress their metaphysical tendencies "must project their conceptions into realities beyond perception. Both physicist and biologist are equally under obligations to withdraw from the metaphysical limbo beyond sense-impression." To recognize that the contents of the mind ultimately take their origin in sense-impressions removes metaphysics "from the field of knowledge." 10 The phenomenal world should be distinguished from "the unreal products of metaphysical thought." 11

The metaphysician is, thus, a man who refuses to confine his world within the limits of sense-impressions and mental constructs of such. He attempts to pass beyond the confines, not merely of actual, but even of possible, human knowledge. Professor Pearson

reprimands him for this, and he endeavors to make clear just where we must place the limits of the knowable.

He tells us that a message is carried by a sensory nerve to the brain. At the brain what we term the sense-impression is formed, and probably some physical change takes place which remains with a greater or less degree of persistence in the case of those stored sense-impressions which we term memories. “Everything up to the receipt of the sense-impression by the brain is what we are accustomed to term physical or mechanical; it is a legitimate inference to suppose that what from the psychical aspect we term memory has also a physical side, that the brain takes for every memory a permanent physical impress, whether by change in the molecular constitution or in the elementary motions of the brain substance, and that such physical impress is the source of our stored sense-impression. These physical impresses play an important part in the manner in which future sense-impressions of a like character are received. If these immediate sense-impressions be of sufficient strength, or amplitude as we might perhaps venture to say, they will call into some sort of activity a number of physical impresses due to past sense-impressions allied, or, to use a more suggestive word, attuned to the immediate sense-impression. The immediate sense-impression is conditioned by the physical impresses of the past, and the general result is that complex of present and stored sense-impressions which we have termed a 'construct.'" 1

Now a message which has been conducted to the brain along a sensory nerve may be reflected directly as an outgoing message along a motor nerve. In this case a sense-impression can be received without our recognizing it, without our being conscious. Again, the sense-impression received may arouse stored senseimpressions. In this case we are conscious, we think: "Thus what we term consciousness is largely, if not wholly, due to the stock of stored impresses, and to the manner in which these condition the messages given to the motor nerves when a sensory nerve has conveyed a message to the brain. The measure of consciousness will thus largely depend on (1) the extent and variety of past sense-impressions, and (2) the degree to which the brain can permanently preserve the impress of these sense-impressions, or what might be termed the complexity and plasticity of the brain." 2