plain man, for he must have, as we have seen, a something in which ideas may inhere or to which they may in some sense belong. Still, it is a possible doctrine, and it may not without justice be regarded as a development from or a modification of the plain man's doctrine. That they have much in common becomes evident just as soon as we endeavor to make quite clear what is meant by the statement that ideas are determinative of motions in matter.

We are to conceive that a detailed knowledge of all the motions of all the atoms constituting the body of the boy who is chasing the dog would reveal that we are not dealing with a perfect mechanism. At some point there is a break. All the motions which have preceded will not account for all the motions that follow. We must fill up this gap with ideas and suppose them to be capable of being affected by the machine and, in turn, of affecting it. In other words, the ideas become, at least for the time being, a part of the machine.

Now, that ideas should become even for an instant a part of the machine can seem simple and natural only to one who has no clear conception of all that this implies. If the statement that matter can act upon ideas and ideas upon matter is to mean anything at all, and is not to remain an empty collocation of sounds, we must conceive the ideas to be present in the body. The machine needs patching up at the break, and the insertion of a coupling which is not present is manifest nonsense. If the ideas are not entities which exist in space, if they are nowhere, then they are, of course, no nearer to the point at which they are needed than they are to any other point in the body. Indeed, they are no nearer to this point than they are to any point in any other body, and the notion of the insertion of ideas to fill a gap simply lapses.

Descartes realized this truth perfectly well, and he took care to put his soul in the little pineal gland, where it could do the most good. If we deny that the things which interact are present to each other, if we deny that they form part of the same system in space, we exenterate our notion of interaction, and it becomes a mere shell. As a matter of fact, we do not have to go far afield to discover that those who trace the series of changes which run from the periphery of the body along the afferent nerves, and the series of changes which run from the central nervous system along the efferent nerves, and find it impossible to connect these with each other except with a coupling of ideas we do not, I say,

have to go far to find that these vaguely assign to ideas a spatial presence, and put them between the two sets of changes. They do precisely what the plain man does with his atomic self, and they do it, just as he does, without a clear recognition of what it is that they are doing.1

If, then, the ideas are to be built into the machine in even a semi-intelligible sense, they must be conceived to be present in the body. We have seen above that, when we strive to get a clear understanding of the nature of the presence of the atomic self in the body, we discover it to be a dimly imagined material presence. Here the case is the same. But this vague attribution to ideas of a material presence must go the way of all misconceptions when its true significance is brought to light.

Let us suppose that the idea thus made determinative of motions in matter is that of a yellow dog. Shall we place this at a definite point in the mist of moving atoms that constitute the boy's brain? Can atoms move toward it and away from it? Can they touch it? Can it move from place to place? Is it spread out in space as it seems to the boy to be, or must we assume it to be a mathematical

1"If feelings are causes, of course their effects must be furtherances and checkings of internal cerebral motions, of which in themselves we are entirely without knowledge. It is probable that for years to come we shall have to infer what happens in the brain either from our feelings or from motor effects which we observe. The organ will be for us a sort of vat in which feelings and motions somehow go on stewing together, and in which innumerable things happen of which we catch but the statistical result. Why under these circumstances we should be asked to forswear the language of our childhood I cannot well imagine, especially as it is perfectly compatible with the language of physiology. The feelings can produce nothing absolutely new, they can only reinforce and inhibit reflex currents, and the original organization by physiological forces of these in paths must always be the groundwork of the psychological scheme.

"... The nerve-currents, coursing through the cells and fibres, must in this case be supposed strengthened by the fact of their awaking one consciousness and dampened by awaking another. How such reaction of the consciousness upon the currents may occur must remain at present unsolved.

"... Habitual actions are certain, and being in no danger of going astray from their end need no extraneous help. In hesitant action there seem many alternative possibilities of final nervous discharge. The feeling awakened by the nascent excitement of each alternative nerve-tract seems by its attractive or repulsive quality to determine whether the excitement shall abort or shall become complete. Where indecision is great, as before a dangerous leap, consciousness is agonizingly intense. Feeling, from this point of view, may be likened to a cross-section of the chain of nervous discharge, ascertaining the links already laid down, and groping among the fresh ends presented to it for the one which seems best to fit the case." - JAMES, "Psychology," Chapter V.

point? If it cannot lie between two atoms, approach and be approached, touch and be touched, in what sense can it be declared to be present? He who talks vaguely of its presence, and does not raise any of these questions, is walking in thick darkness and is unaware of that fact. He dimly conceives ideas to be material, just as the plain man dimly conceives of the atomic self as material. He puts them in space, and yet he would shrink from the consequences that this entails, did he realize what those conse

quences are.

This doctrine that ideas may be used to patch up a defective mechanism does not need to be discussed at great length, because it differs so little, in any point that need concern us here, from the doctrine of the atomic self. One is impressed, in studying both the original doctrine and its modification, with the thought that it is exceedingly hard for the human mind to shake itself free from materialistic ways of thinking. Some of those who have been. most anxious not to be accounted materialists have retained the most unmistakable traces of materialistic thought.

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CHAPTER XVIII

THE AUTOMATON THEORY: ITS GENESIS

THUS it seems clear that what is known as the "interaction" theory of the relation of mind and body gains what plausibility it possesses from the covert ascription of materiality to mind. When this is made apparent, and when a resolute attempt is made to remove every materialistic element from the notion of the mind, then it also becomes clear that the attempt to build mind into the bodily mechanism, and to make it, at least for the time being, one of its constituent parts, is nothing less than absurd. The mind is not present to the body in any sense that would permit of its filling a gap in the bodily mechanism. Interaction becomes a mere word, the name of an empty nothing, and the impulse to insist upon it dies of inanition. No clear-minded man can take pleasure in maintaining that there is interaction between mind and body, if the word "interaction" suggests to his mind nothing at all.

But if we dismiss the doctrine of interaction as being rank materialism in disguise, and hence worthy of reprobation, what remains to us? There remains, for one thing, the doctrine of the physical automaton with parallel mental states, and this has been the refuge of many who have felt themselves forced out of the position occupied by the interactionist. What can be said for and against this doctrine?

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That the human mind is related to the human body as it is not related to other material things was discovered by man long before there was a science of psychology. But the problem of the mind's more definite localization a materialistic form of expression somewhat justified by custom was and had to remain an insoluble problem until men gained some definite knowledge of the structure of the human body and of the mode of functioning of its various parts. Thus, at the time of their promulgation, no authoritative denial could be given to the Atomistic doctrine that the brain is the seat of thought, the heart of anger, and the

liver of desire; to the doctrine of Critias, who regarded the blood as the seat and substratum of the soul; to that of Plato, who distributed his tripartite soul in the head, the chest, and the region below the diaphragm; or to that of Aristotle, who relegated the brain to a subordinate place in the animal economy and found the heart to be the seat of sensations.

Not until the beginnings of modern philosophy and that revival of the study of nature which has resulted in the several sciences as we now have them, did man come into the possession of such information as would justify him in definitely and finally rejecting the one or the other of the above-mentioned doctrines, and in expecting all those who follow his arguments to be compelled by their cogency to accept his conclusions. In place of conflicting opinions, more or less arbitrarily taken up upon a basis of slender and uncertain evidence, there has emerged a body of facts that it is not too much to call scientific, and that we find presented in substantially the same form by all reputable writers upon physiology and physiological psychology. It remains to render our knowledge upon the subject more complete and definite, and it also remains to interpret its significance, but it seems to be no longer an open question whether the whole edifice which has been built up by successive generations of investigators shall be allowed to stand, or shall be torn down in order to make room for a quite different structure. One may hold tentatively some of the conclusions arrived at by Goltz, or Munk, or Ferrier, or Luciani, and may be strongly inclined to wait for more light before turning them into articles of faith; but no reasonable man can in our day revert to the doctrine of Aristotle, or cast in his lot with the Atomists.

The honor of having laid enduring foundations for this edifice must be accorded to Descartes, whose careful study of the structure of the human body revealed to his discriminating eye that it is a mechanism of vast complexity and of the most perfect adjustment. In particular he comprehended the significance of the brain as a central organ and the meaning of the distribution of the nerves which connect it with every part of the body. He writes:

"We must know, therefore, that the human soul, although it is united with the whole body, has, nevertheless, its chief seat in the brain, in which alone it not only understands and imagines,