It is quite clear that the phenomena of dreams could be perfectly accounted for by natural laws and therefore they should not be attributed to supernatural causes.

Ancient divines taught that dreams either proceeded from the Deity or from the devil, but it is now quite certain that all dreams originate only in the dreamers. Dreams come only from a state of imperfect sleep. When sleep is perfect, all the faculties are at complete rest, and there can be no dreams—and even if there were, memory being absent, the dream could never be recalled. Bodily sensations are the most common cause of dreams. A hot-water bottle at the feet might cause dreaming of a fire; kicking the bed-clothes from the lower extremities might carry the dreamer to scenes of snow and ice; getting one's head accidentally under the pillow might involve the dreamer in a drowning episode or other incident of strangulation. Physical ills also have their influence upon the unsound sleeper, and the nature of the pain is usually similar to the nature of the dream. The mind, during unsound sleep, is irrational, and often groups incongruous things and scenes into meaningless and impossible situations. Stored away in hidden recesses of the memory, are innumerable items, and during imperfect sleep the mind seizes some of these haphazard and forms some of the most fantastic and ludicrous pictures.

The cause of the dream is sometimes the cause of its fulfilment. For example, a person might think, in his waking moments, of writing a poem, and if it is strongly on his mind he is likely to dream of it. The dream may suggest some missing link or idea, and when he awakes he is better prepared to complete it. Belief in the supernatural origin of dreams is also the frequent cause of their fulfilment. If a person dreams of approaching sickness, and is superstitious, his fears and imagination are likely to hasten the calamity. There is recorded somewhere in history the case of a general who dreamed of a defeat, and, being superstitious, his courage deserted him, and the enemy conquered. There is also recorded the case of a German student, who dreamed that he was to die the next day at a certain hour. His friends found him next morning making a will and other preparations, and as the time drew near, he had every appearance of a person about to die. His friends used every argument to shake his belief in dreams, but to no purpose, and they were despairing of saving him, when the physician contrived to set the clock forward, and thus prolonged matters until the student's life was at last saved. There are several instances on record where death has actually ensued in consequence of the belief in the supernatural origin of dreams, and there is no doubt that believers in dreams often cause fulfilment by mental influence. It is true that there are instances on record where a person has dreamed of the death of a relative, and found that that relative had died at about the time of the dream, but these instances are rare and prove nothing. When it is considered that there are doubtless millions of instances where persons have dreamed of the death of relatives, when they have not died, the comparatively few cases where the dreams came true must be taken as mere coincidence. It is not a miracle for a dream of this kind to come true, but it would indeed be a miracle if one or more of such dreams did not come true, like the one that is recorded of a proud young divinity student who dreamed three times in one night that he must turn to the seventh verse of the fifth chapter of Ecclesiastes, where he would find important instructions. He arose in the morning, and turning to the specified passage, found this: "In the multitude of dreams there are divers vanities."

The mental process by which the human mind arrived at the conclusion that dreams result from supernatural causes is due to the same propensity of the mind for the marvelous, and to that excess credulity which attributes all unusual or remarkable mental impressions to some external agency. The average mind is prone to reason out the causes of phenomena to the limit of its mental powers, and then, when it arrives at the point when it can go no farther, and can give no rational explanation, to attribute the phenomena to the supernatural.

All dreams originate from former sensations. These sensations were introduced into the mind by the senses, at some previous time or times, and the mind has stored them away where they have lain dormant and forgotten. The dream-state is that condition of temporary subconsciousness when the memory recalls the aforesaid sensations and submits them to the scrutiny of the reasoning faculty, by which their relations are determined, through the agency of association. During perfect sleep there can be no dream, because the dream is caused by a state of activity of certain faculties, which, in perfect sleep, are in a state of torpor. There could be no dream if the mental faculties, including memory, are at perfect rest. Only when part of the mental faculties are sufficiently active to recall the sensations and impressions that are stored away, and to institute association, can there be dreams. Some of the faculties must be active, and some inactive, to produce a dream, and only in imperfect sleep does this condition obtain. Among the inactive faculties in the dream state is judgment, which, were it active, would correct the mental process and discover the fallacy. Imagination is often brought strongly into play by the dreamer; and the combination of imagination, previous sensations and associations often create fantastic objects and pictures wholly different from those occurring in nature. The mind of the dreamer can readily combine parts of the sensations previously derived from beholding an elephant, a crow and a cow, and may see in his dream a crow with a trunk, a cow with a bill, or an elephant with upright horns and a black feathered tail. It can also readily associate with his own self parts of various sensations derived from reading or hearing of certain crimes or improprieties, and picture himself in the act of doing things utterly at variance with his morals and inclinations when in a conscious state.

It also may happen, in the various modes of combination, that objects or events are portrayed in accordance with nature and facts, but, perhaps, in exaggerated, diminished or distorted forms, in which case an erroneous standard of judgment is formed that will throw all after sensations out of perspective with truth.

The dreamer generally dreams of things which have lately been weighing on his mind, but not necessarily so, nor does it follow that he will dream what has been ardently expected or painfully dreaded. Association of ideas may lead his unguided mind to a scene or object which, in his wakeful moments, he cannot trace, for his memory usually preserves only the final objects or scene, and not the various steps that led to it. Thus, if moving be on his mind, he may, in his dream, see a moving van, then a painting on the side of the van, then an artist, then a paint shop, a model, another picture on an easel, and finally a very pleasant or a very horrible scene in a studio. When the dreamer awakes he remembers only the scene, and he is at a loss to know why he should have dreamed of a scene so foreign to his previous thoughts.

There appears to be no truth whatever in the theory that dreams come as omens or warnings, for they are purely accidental. Neither is there apparently any truth in the belief that dreams come by opposites, that they are the manifestation of some invisible agency, or that there is anything supernatural, uncanny or mysterious about them.

To maintain that one can foretell future events, or read past events, from dreams, is absurd. Nearly every person dreams each night, and particularly during the moments when losing consciousness and the moments when awakening, since imperfect sleep then obtains; and, it would be strange indeed if, during one or more of these occasions, we did not by chance dream of something which afterwards actually happens.

All bodily derangements that interrupt healthy sleep, such as irritation of the digestive organs, and even over-exertion, worry, and undue excitement, will produce dreams, and it is therefore fairly obvious that, since we know the cause of dreams, their effects and results, there is nothing marvellous, unnatural, wonderful, extraordinary or supernatural in dreams.

Until the past few hundred years, the cause of dreams was not understood. Aristotle believes the cause of dreams to be common sense, but placed in the fancy. Avicen thought it to be an ultimate intelligence moving the moon in the midst of that light with which the fancies of men are illuminated while they sleep. Averroes, an Arabian physician, ascribed it to the imagination. Democritus referred the cause of them to little images, or representations, separated from the things themselves. Plato placed it among the specific and concrete notions of the soul. Albertus attributed dreams to superior influences, which continually flow from the sky, through many specific channels.

In order to disdelusionize, it will be necessary to get a clear understanding of the nature of the mind and of its workings. "When the mind turns its view inward upon itself," says John Locke, "and contemplates its own actions, thinking is the first that occurs. In it, the mind observes a great variety of modifications, and from them receives distinct ideas. Thus the perception, which actually accompanies, and is annexed to any impression on the body, made by an external object, being distinct from all other modifications of thinking, furnishes the mind with a distinct idea which we call sensation; which is, as it were, the actual entrance of an idea into the understanding by the senses.

"The same idea, when it occurs again without the operation of the like object on the external sensory, is remembrance; if it be sought after by the mind, and with pain and endeavor found, and brought again in view, it is recollection; if it be held there long under consideration, it is contemplation; when ideas float in our mind without any recollection or regard of the understanding, it is that which the French call reverie; our language has scarce a word for it. When the ideas that offer themselves (for, as I have observed, while we are awake, there will always be a train of ideas succeeding one another in our minds) are taken notice of, and, as it were, registered in the memory, it is attention; when the mind, with great earnestness, and of choice, fixes its view on any idea, considers it on all sides, and will not be called off by the ordinary solicitations of other ideas, it is what we call intention or study. Sleep without dreaming is rest from all these; and dreaming itself, is the having of ideas (while the outward senses are stopped, so that they receive not outward objects with their usual quickness) in the mind, not suggested by any external objects, or known occasion, nor under any choice or conduct of the understanding at all, and whether that which we call ecstasy, be not dreaming with the eyes open, I leave to be examined."

We often converse with a dead or absent friend, in our dreams, without remembering that the grave or the ocean is between us. We float, like a feather, or fly like a bird, upon the wind, one moment in New York, and the next in Melbourne, without reflecting that the laws of nature are suspended, or inquiring how the scene could have been so suddenly shifted. We accommodate ourselves to every event, however romantic, impossible, unreasonable, extravagant and absurd.

We also dream awake, which dreams may be called reveries or waking-dreams, and they are sometimes as chimerical, and impossible to be realized, as our sleep dreams. Many fabulous stories of apparitions, magic, and apparent miracles, owe their origin to some form of dream.