The second difficulty.

The second conviction from which speculative difficulties have resulted, refers, not to the general nature of spirit, but to a specific characteristic. It is held that the soul is unextended, and we are asked, "How can matter, the extended substance, have any causal connection with mind, a substance devoid of extension?" The argument runs thus: "Nothing can touch and be touched but what is extended; and if the soul be unextended, it can have no connection by touch with the body: the physical influence, therefore, is inconceivable and impossible." This reasoning, in which, however, the word "touch" signifies merely juxtaposition in space, implies the truth of two statements: first, that an unextended substance cannot affect, or be affected by, an extended substance; and secondly, that the soul is an unextended substance.

The first of these statements, we think, may be accepted as correct, if by an unextended substance we mean one which does not in any way pervade or occupy space; for a substance which absolutely does not occupy or pervade any portion of space is inconceivable. We may conceive of a substance pervading space in such a way as not to interfere with the occupancy of the same space by other substances of a coarser nature; but no substance could exist without any room at all. Not even the most insignificant soul could exist within a mathematical point. If, therefore, by an unextended substance we are to understand one which has no relations to space save those of position only, then we not merely admit that such an object could not be affected by material changes, but we deny that either the soul or anything else is a substance of this character. In short, we reject the view of Descartes and many other learned men, that spirits do not in any sense occupy space, and incline to the belief that the soul, in some subtile way, pervades and possesses the sensory system.

The soul a simple substance

which pervades the sensorium. Aristotle.

4. We have no reason to suppose that the soul has shape and parts like the body, or even that it is a composite substance. The probable opinion is, that it is a simple substance endowed throughout with various powers, and that, if not always present, it is capable Early Chris of becoming instantly present, either successively or simultaneously, at different points of the sensorium, as these may be acted on by material agents. The soul certainly seems to exercise, in that part of the body which may be affected, that mode of sensation which corresponds to the peculiar action of the nerves of that part.

tians.

But, possibly, in times of quiescence or of sleep, the spiritual substance may retire wholly to the brain.

The doctrine of the pervading presence of the soul was taught by Aristotle, who held that the soul is all (that is, with all its powers), in every part of the body. This was also the view commonly entertained in the early days of Christianity. The epistle to Diognetus- an eloquent letter, probably written by Justin Martyr, but certainly addressed by some eminent Christian in the first or second century to an equally eminent pagan

contains the following passage: 66 That," says the author, "which the soul is in the body, the same are Christians in the world; for the soul is diffused through all the members of the body, and Christians through all the states of the world. The soul dwells, indeed, in the body, but is not of the body; and Christians dwell in the world, but are not of the world."

Descartes' doctrine:

extended.

The prevalence, in modern times, of the opinion that the soul does not occupy space, may be traced to the soul un- the writings of René Descartes, who, in the second quarter of the seventeenth century, revolted against the traditional dogmas of the Middle Ages, and formed for himself a new philosophy. One of his favorite doctrines was that the essence of matter is extension, and that the essence of the mind is thought, that matter is the extended unthinking substance, and that mind is the thinking unextended substance. This doctrine was incorporated into the philosophy of Europe, and has been maintained as the proper opposite of materialism. The influence of it is apparent in the earlier teachings of the Scotch school. For example, Dr. Thomas Reid, one hundred years after Descartes, ridicules the idea that one's mind can be present in his toe, so as to feel pain there. "Philosophers," he says, "have disputed much about the place of the mind, yet none of them ever placed it in the toe."

Though Descartes maintained that the soul can exist without being extended, he allowed that it must have a place or location. He supposed that it resides in the pineal gland, a small gland in the centre of the brain. His followers, also, endeavored to account for a fact which he himself did not admit, namely, that the soul and body directly influence each other. "The soul," said they, "may be compared to a spider seated in the centre of its web. The moment the least agitation is caused at the extremity of this web, the insect is advertised, and put upon the watch. In like manner the mind, situated in the brain, has a point on which all the nervous filaments converge; it is informed of what passes at the different parts of the body, and forthwith it takes its measures accordingly. The body thus acts with a real efficiency on the mind, and the mind acts with a real efficiency on the body."

The tendency, of late years, has been to return to the ancient belief in the spaciality of spirit. Sir William Hamilton, though confessing himself in perplexity, annotates on Reid as follows: "Both in ancient and modern times the opinion has been held that mind has as much a local presence in the toe as in the head. The doctrine long generally maintained was that, in relation to the body, the soul is all in the whole, and all in every part. . . . The first condition of the possibility of an immediate, intuitive, or real, perception of external things, which our consciousness assures us that we possess, is the immediate connection of the cognitive principle with every part of the corporeal organism. .. That the pain is where it is felt, is the doctrine of common sense. We only feel inasmuch as we have a body and a soul; we only feel pain in the toe inasmuch as we have such a member, and inasmuch as the mind, or sentient principle, pervades it. We just as much feel in the toe as we think in the head." President Porter, also, expresses himself in similar terms.

The teach

ilton and

Porter.

The view of Hamilton and Porter involves that not ing of Ham- merely the feeling, but also the initial or primary perception of it, takes place where the bodily affection occurs. At the same time this cognition, though as local as the sensation, is, of itself, extremely indefinite. It is perhaps the lowest possible form of intellectual action. The completed and measured estimate of the distances and direction of sensations from one another, and the exact determination of the places of feelings with reference to the parts of the body, are judgments which follow upon the comparison and construing together of the primary perceptions of the sensations; and the formation of these definite judgments requires some time and experience.

Moreover, the mind, while the body is yet whole, having used these secondary judgments and found them trustworthy, adopts them as rules of belief in regard to all sensations which may take place in the same general region or direction; and the habit of conclusion thus formed is not easily laid aside. This may explain the fact that after the amputation of a limb, it is often difficult for one to realize that he has lost a hand or a foot. With some individuals the tendency to erroneous judg ment does not remain long; with others it lasts for years.

CHAPTER V.

THE EFFICIENCY PRODUCING SENSATION.

1. SIR WILLIAM HAMILTON, in the sixteenth lecture of his metaphysical course, shows what difficulties have arisen in philosophy concerning the causal connection between soul and body, and confesses that he himself, having failed of a satisfactory solution, had resolved to rest in a "contented ignorance." Before further discussion in regard to this connection, it may be instructive to consider briefly the strange hypotheses which those were driven to adopt who, for various reasons, believed that neither agent can directly act upon the other. Beside the ancient Aristotelian doctrine of direct influence, which we regard as the correct view, three hypotheses have been devised.

The plastic

The first of these, in point of time, was the hymedium. pothesis of the plastic medium. It is to be traced to Plato, who teaches that the soul employs the body as its instrument; but that the energy, or life and sense, of the body is the manifestation of a different substance, of a substance I which holds a kind of intermediate existence between mind and matter." The Alexandrian Platonists specially elaborated this idea; and "in their psychology, the oxos, or vehicle of the soul, the medium through which it is united to the body, is a prominent and distinctive principle." Saint Augustine inclined to this view; and it has been adopted by some eminent modern philosophers.

causes.

Occasional The second hypothesis is that of occasional causes. By an occasional cause is meant a cause which is only the occasion of some effect, and which does not contribute at all to the efficiency producing the effect. This theory is also named the hypothesis of divine assistance, because God is regarded as the real causal agent between mind and body. According to this view, "the brain does not act immediately and really upon the soul; the soul has no direct cognizance of any modification of the brain. This is impossible. God himself, by a law which he has established, when movements are determined in the brain, produces analogous modifications in the conscious mind. In like manner, in case the mind has a volition to move the arm, this volition of itself would be inefficacious; but God, in virtue of the same law, causes the answering motion in the limb. The body, therefore, is not the real cause

of the mental modifications, nor the mind the real cause of the bodily movements." This doctrine was first advocated by Malebranche and other followers of Descartes; Dr. Reid inclined to it, and it was maintained by Professor Stewart.

Pre-estab

ture.

The third hypothesis, which is the most curious lished har- of all, is that of predetermined harmony. It was mony. originated by Leibnitz. According to it, soul and body have no communication, no mutual influence. "The soul passes from one state to another by virtue of its own naThe body executes the series of its movements without any participation or interference of the soul in these. The soul and body are like two clocks, accurately regulated, which point to the same hour and minute, although the spring which moves the one is not that which moves the other. This harmony was established before the creation of man, and hence is called the pre-established or predetermined harmony."

We object to all these theories, that they are mere hypotheses devised to meet a difficulty which originates in mistaken views, and that they are devoid of support save such as can be found from their fitness for that end. We can find no evidence of any medium of communication between soul and body, or of any divine interference to produce sensations and carry out volitions, or of that marvellous foreordained correspondence between corporeal changes and the life of the soul. On the contrary, both our natural convictions and our critical observations indicate that we actually are influenced by affections of the body. The mind refers its sensations to antecedents immediately present, yet outside of itself; our very conceptions of the sensible qualities and changes of matter are essentially conceptions of the causes of various forms of sensation as related to these effects, and we intuitively ascribe efficiency to these causes. Our sensations, therefore, are perceived as really resulting from the body and things affecting the body. When we handle a stone, its weight, hardness, roughness, and coldness are real causes producing effects corresponding to them in us. All this we firmly believe till confused by some philosophical subtilty. Let us remember that difficulties on this subject have resulted simply from an undue contrasting of mind and matter, of soul and body, as things different in nature, and we shall have no trouble in accepting the teachings of intuition. These two substances differ, perhaps, as far as substances can differ, but not so far as to be incapable of mutual influence. This whole subject brings before us one of those frequently recurring cases in which the best philosophy is found to accord with the ordinary convictions of mankind.