We shall understand the different symptoms of hypnosis much more easily if we recognize certain facts in the mental life of human beings. They are of immense importance to psychology, physiology, medicine and jurisprudence, as well as to hypnotism. The facts to which I refer are - (1) Men have a certain proneness to allow themselves to be influenced by others, and at the same time to believe much without making conscious logical deductions; (2) a psychological or physiological process tends to appear in a man if he believes it will; (3) a man's susceptibility to influence based on the two preceding facts is often specially marked in respect to some particular person; (4) capability of being influenced in this way is generally increased if a person has learned by previous experience that he has a tendency in this direction;

(5) besides the ordinary state of waking consciousness there is another, which we may term dream-consciousness; it is brought about by certain definite physiological and pathological conditions, is capable of developing those characteristics of the human mind which we are now discussing very considerably, and is specially noticeable for its influence on sense-perception. Let us begin by considering the first point. There are people who believe that they can escape external mental influences; but they are wrong. Life is full of such influences, and they will work as long as there is mental activity among men. The desire for society, the necessity of exchanging opinions, show our proneness to influence others or be influenced by them. In this way we often attempt to convert a scientific or political opponent.

In such a case, of course, we generally endeavour to attain our object by producing logical proofs. But, that men have a tendency to believe things without complete logical proof cannot be doubted for one moment. We will call this quality credulity. There is no man who believes only what has been logically proved to him. A conscious logical conclusion is hardly ever the immediate result of a sense-perception, yet we form our judgment of external objects as if that were really the case. Most people confuse the subjective idea of an object with the object itself (Spencer); whereas the latter, the "thing in itself," as Kant calls it, is quite unknown to us. But apart from the delusions of judgment which we make with regard to our sense-impressions, we find that human credulity ranges over a very wide field. It is emotional emphasis, in particular, that causes the processes which exert an influence on credulity. We easily believe anything we want to hear, and it is a matter of common experience that a patient is much more ready to believe the quack who tells him he will get well than the doctor who declares his malady incurable.

This is to a great extent the result of the influence of the quack, who, knowing full well the weakness of his patients in this respect, promises them recovery from even absolutely incurable diseases, a promise which no honourable medical man could possibly make. Also, the constant repetition of an assertion facilitates belief in its accuracy. The success of those clever advertisements from which no one escapes, least of all the very people who consider themselves secure against such allurements, makes this particularly clear; and the history of hypnotism shows plainly what a power the constant repetition of an assertion has. Twenty years ago most people believed that there was really no such thing as hypnotism and that any belief in it was attributable to self-deception on the part of the experimenter or fraud on that of the subject. Since that time a complete reaction has set in and opinion has changed, influenced to no slight extent by the constant accessions to the ranks of those investigators by whom the reality of hypnotism was originally maintained. Doctors and others have changed their opinions about hypnotism, not because it has been definitely demonstrated to them, but because they have been influenced by constantly hearing and reading the same assertions about it.

To this we may add that faith in authority has also played a definite, though not exclusive, part. For even after Charcot, Heiden-hain, and a number of other authorities had admitted the reality of hypnosis, many people still believed the whole thing to be a swindle and that those investigators had been deceived. Certainly, the personality of any one who wishes to influence another's belief plays a special part. I shall return to this point later on.

I will now proceed to discuss the second of the facts of human mental life given above - i.e., the physiological and psychological, action of belief. Carpenter, Hack Tuke, and other English investigators long ago ascribed great importance to strained expectation - "expectant attention," they termed it. The second of these factors must be strictly separated from the first. It is quite possible to believe something without the action corresponding to that belief taking place. A man may believe that he has taken an anodyne powder without the pain for which it was taken subsiding. For belief to be effective a particular mental predisposition is certainly requisite. We cannot analyze this predisposition in all cases; it may be present on one occasion, absent on another. We find exactly the same thing apart from hypnosis - e.g., in pathology. I have already mentioned that people who suffer from dread of blushing are particularly liable to blush when they most dread they will do so. Other pathological cases present similar phenomena.

At present we are only able to establish the fact that.in ordinary life - i.e., outside hypnosis, there is occasionally a predisposition to be influenced psychologically and physiologically by belief in something.

A few examples will illustrate this effect of belief. It often occurs that people vomit if they think they have taken an emetic, although they have not taken anything of the kind. A person who goes to bed believing he has taken a sleeping powder often falls asleep, even if the powder only contains some inert substance. These phenomena are particularly noticeable in pathological cases. Hysterical paralysis is often cured at the exact moment the patient expects. Many apparently mysterious effects may be explained in this way. Hysterical patients can occasionally foretell an improvement in their paralysis. That recovery should follow need not surprise us if we remember the foregoing remarks, for the connection is totally different from what believers in the gift of prophecy think. The hysterical patient is cured at a particular moment because he expects to be, and the prophecy is thereby apparently fulfilled. Pathological phenomena also frequently occur when expected by the patient - for example, impotentia coeundi of mental origin, stammering and other disorders of speech. Let me here call attention to a mistake that is frequently made: people confuse the expectation of a state with the wish for it.