Part I, Chapter II

OF IMAGINATION

That a thing at rest will remain at rest forever unless something else moves it is a truth no one doubts. But that a thing in motion will move forever unless something else stops it is not so readily accepted, although the reason is the same: nothing can change itself. For people measure not only other people but all other things by themselves. Finding themselves subject to pain and fatigue after moving, they think everything else tires of motion and seeks rest of its own accord, hardly considering whether the desire for rest they find in themselves might itself consist in some other motion. This is why the Schools say that heavy bodies fall downward from an appetite for rest and for preserving their nature in the place most proper to them. They absurdly ascribe to inanimate things an appetite and knowledge of what is good for their preservation—more knowledge than man possesses.

Once a body is in motion, it moves forever unless something else impedes it; and whatever impedes it cannot extinguish its motion instantly, but only gradually, over time. We see that although the wind dies down, waves go on rolling in the water for a long time afterward. So too with the motion produced in the inward parts of a person when he sees, dreams, and so forth. After the object has been removed, or the eye closed, we still retain an image of what we saw, though fainter than when we see it. The Latins call this imagination, from the image formed in seeing, and apply the same name, improperly, to all the other senses. The Greeks call it fancy, meaning appearance, a term as proper to one sense as to another. Imagination, therefore, is nothing but decaying sense; it occurs in human beings and many other living creatures, asleep as well as awake.

The decay of sense in waking people is not a decay of the motion made in sense, but an obscuring of it, as sunlight obscures the light of the stars. The stars exert their power to be seen no less by day than by night; but because, among the many impacts that our eyes, ears, and other organs receive from external bodies, only the predominant one is perceptible, the sunlight predominates and we do not perceive the action of the stars. Once any object has passed from our sight, its impression remains in us; yet, as other, more immediate objects come and act upon us, imagination of the past grows dim and weak, like a person's voice amid the noise of the day. It follows that the more time has passed since we saw or sensed an object, the weaker our imagination of it becomes. For the continual changes in the human body destroy over time the parts moved by sensation. Distance in time and distance in space thus have the same effect upon us: at a distance, what we look at appears dim, with its smaller parts indistinct, and voices grow faint and inarticulate; likewise, after a long time, imagination of the past grows weak, and we lose, for example, many individual streets from cities we have seen, and many particular circumstances from actions. When we wish to express the thing itself—I mean the fancy itself—we call this decaying sense imagination, as I said before. But when we wish to express its decay and signify that the sense is fading, old, and past, we call it memory. Imagination and memory, then, are one thing with different names according to how we consider it.

Much memory, or memory of many things, is called experience. Again, imagination deals only with things previously perceived by sense, either all at once or in parts at different times. The former kind, imagining the whole object as it appeared to sense, is simple imagination, as when one imagines a man or a horse one has seen before. The other kind is compound imagination: from seeing a man at one time and a horse at another, we conceive a centaur in our minds. Likewise, when a man combines the image of his own person with the image of another man's actions, imagining himself a Hercules or an Alexander—as often happens to people deeply taken with romances—this is compound imagination, or, strictly speaking, a fiction of the mind. There are also other imaginations that arise in people, even while awake, from a strong impression on the senses. After gazing at the sun, for example, its impression leaves an image before our eyes for a long time; and after attending long and intensely to geometric figures, a person may see images of lines and angles before his eyes in the dark, although awake. This kind of fancy has no particular name, since it seldom enters into people's conversation.

The imaginations of those who sleep are what we call dreams. These too, like all other imaginations, have previously been present in sense, either whole or in parts. Because in sleep the brain and nerves, the necessary organs of sense, are so numbed that external objects do not easily move them, no imagination—and therefore no dream—can occur in sleep except one arising from agitation of the inward parts of the body. When those parts are disturbed, their connection with the brain and other organs keeps those organs in motion, so that images formed there earlier appear as if a person were awake. But since the organs of sense are now numbed, there is no new object to overpower and obscure those images with a stronger impression; amid this silence of sense a dream is necessarily clearer than our waking thoughts. Hence it is difficult, and many think it impossible, to distinguish exactly between sensation and dreaming. As for me, I consider that in dreams I do not often or consistently think of the same people, places, objects, and actions as when awake, nor do I remember as long a chain of connected thoughts in dreams as at other times. And since when awake I often notice the absurdity of dreams, but never dream of the absurdities of my waking thoughts, I am satisfied that when awake I know I am not dreaming, although when I dream I think myself awake.

Since dreams are caused by disturbances of some inward parts of the body, different disturbances must cause different dreams. Thus lying cold gives rise to dreams of fear and calls up the image of some frightening object, the motion from the brain to the inner parts and from the inner parts to the brain being reciprocal. Just as anger causes heat in some parts of the body while we are awake, so when we sleep, overheating in those same parts causes anger and raises the image of an enemy in the brain. In the same way, just as natural affection when we are awake causes desire, and desire produces heat in certain other parts of the body, so excessive heat in those parts while we sleep raises in the brain an image of affection shown to us. In short, our dreams reverse our waking imaginations: the motion begins at one end when we are awake and at the other when we dream.

It is most difficult to distinguish a dream from waking thoughts when by some accident we do not notice that we have slept. This can easily happen to someone full of fearful thoughts and troubled in conscience, who sleeps without the usual business of going to bed or undressing, as when nodding off in a chair. A person who takes care and deliberately lies down to sleep, on the other hand, cannot easily mistake any strange and extravagant fancy that comes to him for anything but a dream. We read that Marcus Brutes, whose life Julius Caesar had spared and who was also his favorite, but who nevertheless murdered him, saw a dreadful apparition at Phillipi on the night before he gave battle to Augustus Caesar. Historians commonly relate it as a vision, but from the circumstances one may readily judge that it was only a brief dream. Sitting in his tent, brooding and troubled by the horror of his rash act, he could easily have dreamed as he dozed in the cold of the thing that frightened him most. As his fear gradually woke him, so it must also have made the apparition gradually vanish. Having no assurance that he had slept, he had no reason to think it a dream rather than a vision. Nor is this very rare: even people fully awake, if timid and superstitious, filled with frightening tales and alone in the dark, are subject to similar fancies and believe they see spirits and ghosts of the dead walking in churchyards. Yet it is either their fancy alone, or the trickery of people who take advantage of such superstitious fear to travel in disguise at night to places they would not want to be known to visit.

From ignorance of how to distinguish dreams and other powerful fancies from vision and sensation arose much of the ancient religion of the Gentiles, who worshiped satyrs, fauns, nymphs, and the like; and from it comes the opinion that unschooled people nowadays hold about fairies, ghosts, and goblins, and the power of witches. As for witches, I do not think their witchcraft has any real power. Yet I think they are justly punished for their false belief that they can do such harm, joined to their purpose to do it if they can; their occupation is closer to a new religion than to a craft or science. As for fairies and wandering ghosts, I think belief in them has deliberately been taught, or left unchallenged, to preserve the standing of exorcism, crosses, holy water, and other such inventions of clerics. There is nevertheless no doubt that God can create apparitions contrary to nature. But it is no article of Christian faith that he does this so often that people should fear such things more than they fear a halt or change in the course of nature, which he also can halt or change. Evil people, however, under the pretext that God can do anything, are bold enough to say anything when it suits them, even if they believe it false. A wise man should believe them no further than sound reason makes what they say credible. If this superstitious fear of spirits were removed, together with forecasts drawn from dreams, false prophecies, and many other things depending on that fear, by which cunning, ambitious people deceive the simple, men would be much better prepared for civil obedience than they are.

This ought to be the work of the Schools; instead, they nourish such doctrines. Not knowing what imagination or the senses are, they teach whatever they receive: some say imaginations arise of themselves, without a cause; others say they arise most often from the will, and that good thoughts are blown, or inspired, into a person by God and evil ones by the Devil; or that good thoughts are poured, or infused, into a person by God and evil ones by the Devil. Some say the senses receive the species of things and hand them to the common sense, which hands them to fancy, which hands them to memory, which hands them to judgment, as if passing objects from hand to hand. With many words, they make nothing understood.

The imagination raised in a person, or any other creature capable of imagining, by words or other voluntary signs is what we generally call understanding; it is common to humans and animals. A dog learns by habit to understand its master's call or rebuke, and many other animals do likewise. Understanding peculiar to humanity is the understanding not only of another's will, but of his conceptions and thoughts, through the sequence and arrangement of the names of things in affirmations, negations, and other forms of speech. Of this kind of understanding I shall speak later.

CHAPTER III. OF THE CONSEQUENCE OR TRAIN OF IMAGINATIONS

OF IMAGINATION

No one doubts that if something is at rest, it will remain at rest forever unless something else moves it. But people are less willing to accept that a moving thing will keep moving forever unless something else stops it, although the reason is the same: nothing can change itself. People judge not only other people but everything else by themselves. Because they feel pain and tiredness after moving, they think everything else grows tired of moving and seeks rest on its own. They hardly consider whether their own desire for rest might itself consist of some other movement. This is why the schools say that heavy bodies fall downward because they want rest and want to preserve their nature in the place most suitable for them. Absurdly, they give lifeless things desires and knowledge of what is good for their preservation—more knowledge than human beings have.

Once a body is moving, it moves forever unless something else gets in its way. Whatever obstructs it cannot completely stop its movement in an instant, but only gradually over time. We see that when the wind stops, waves keep rolling on for a long while. The same happens to the movement inside us when we see, dream, and so on. After an object has gone or an eye is closed, we still retain an image of what we saw, though a dimmer one than when we see it. The Latins call this imagination, from the image produced by sight, and they apply the name to the other senses as well, though strictly it does not fit. The Greeks call it fancy, meaning appearance, a word just as suitable for any sense as for sight. Imagination, then, is only fading sense. Human beings and many other living creatures have it both asleep and awake.

In waking people, the fading of sense does not mean that the movement produced in sensing fades away. Instead, the movement is obscured, as sunlight obscures starlight, although the stars exercise their visible power just as much by day as by night. Among the many impacts that external bodies make on our eyes, ears, and other organs, we sense only the dominant one. Because sunlight is dominant, we do not feel the effect of the stars. Similarly, when an object leaves our sight, its impression remains in us. But other, more immediate objects follow it and affect us. They dim and weaken our imagination of what has passed, just as daytime noise drowns out a person's voice. It follows that the more time passes after we see or otherwise sense an object, the weaker our imagination of it becomes. The continual changes in a person's body eventually destroy the parts moved in sensing. So distance in time and distance in space have the same effect on us. At a distance in space, what we look at appears dim, with its smaller parts indistinct, and voices grow faint and hard to make out. At a distance in time, likewise, our imagination of the past weakens: we lose, for example, many particular streets from cities we have seen and many particular circumstances from actions we remember. When we mean the mental image itself, I call this fading sense imagination, as I said before. But when we mean its fading and point out that the sense is growing faint, old, and past, we call it memory. Imagination and memory are therefore the same thing, given different names when considered in different ways.

A great deal of memory, or memory of many things, is called experience. Imagination can only concern things previously sensed, either as a whole at once or in parts at different times. Imagining an entire object as it appeared to the senses is simple imagination, as when someone imagines a person or horse seen before. The other kind is combined imagination. For example, we may see a person at one time and a horse at another, then picture a centaur. Or someone may join an image of himself to an image of another person's actions, imagining himself to be a Hercules or an Alexander, as often happens to people who love reading romances. That is combined imagination, and strictly speaking it is just a fiction of the mind. Other images arise in people even when awake because a sensory impression is strong. If we stare at the sun, its impression leaves an image of the sun before our eyes for a long time afterward. If someone studies geometrical figures intently for a long time, he may see images of lines and angles in the dark, even while awake. This kind of mental image has no special name, since people do not commonly talk about it.

The imaginings of sleeping people are what we call dreams. Like all other imaginings, they first existed in sense, either whole or in parts. During sleep the brain and nerves, which are necessary organs of sense, are so numbed that external objects cannot easily move them. So no image, and therefore no dream, can arise in sleep except through movements of the inner parts of the body. When those parts are disturbed, their connection to the brain and other organs keeps those organs moving. This makes earlier images appear as if the person were awake. But the sense organs are now numb, so no new object can overpower and obscure these images with a stronger impression. In this quiet of the senses, a dream must be clearer than our waking thoughts. This is why it is hard—and many think impossible—to distinguish sense from dreaming exactly. As for me, I consider that in dreams I do not often or regularly think about the same people, places, objects, and actions as I do when awake. Nor do I remember a chain of connected thoughts as long while dreaming as at other times. When awake, I often notice how absurd dreams are, but I never dream of the absurdity of my waking thoughts. This convinces me that when I am awake, I know I am not dreaming, though in a dream I think I am awake.

Since dreams arise from disturbances in some inner parts of the body, different disturbances must cause different dreams. Lying in the cold thus produces frightening dreams and raises the thought and image of something frightening. Movement between the brain and the inner parts goes both ways. When we are awake, anger heats some parts of the body. So when we sleep, too much heat in those same parts causes anger and raises an image of an enemy in the brain. Likewise, natural affection when we are awake causes desire, and desire heats certain other parts of the body. Too much heat in those parts while we sleep raises an image of affection being shown. In short, our dreams reverse our waking imaginings: the movement starts at one end while we are awake, and at the other while we dream.

It is hardest to distinguish a dream from waking thought when we fail for some reason to notice that we have slept. This easily happens to someone whose thoughts are full of fear and whose conscience is deeply troubled, if he falls asleep without going to bed or taking off his clothes, perhaps dozing in a chair. Someone who deliberately goes to bed and makes an effort to sleep is unlikely to mistake a strange and excessive image for anything but a dream. We read of Marcus Brutes, whose life Julius Caesar spared and who was Caesar's favorite but nonetheless murdered him. At Phillipi, the night before he fought Augustus Caesar, he saw a frightening apparition. Historians commonly describe it as a vision. But from the circumstances, we can easily judge that it was only a short dream. He was sitting in his tent, troubled and brooding over the horror of his rash deed. As he dozed in the cold, it was easy for him to dream of what frightened him most. As his fear gradually woke him, the apparition must also have gradually faded. Because he did not know he had slept, he had no reason to think it a dream rather than a vision. This is not very rare. Even people who are fully awake may be fearful and superstitious, filled with frightening stories and alone in the dark. They may have similar mental images and believe they see spirits and dead people's ghosts walking in churchyards. What they see is either their imagination alone or a trick by people who take advantage of such superstitious fear to move in disguise at night to places they do not want to be known to visit.

Most of the ancient Gentiles' religion arose from not knowing how to tell dreams and other strong imaginings from visions and sense. They worshiped satyrs, fauns, nymphs, and the like. The same ignorance explains what uneducated people today believe about fairies, ghosts, goblins, and the power of witches. I do not think witches have any real magical power. Yet I think their punishment is just, because they falsely believe they can cause such harm and intend to cause it if they can. Their trade is closer to a new religion than to a craft or science. I think belief in fairies and wandering ghosts has been deliberately taught, or at least left unchallenged, to maintain the reputation of exorcisms, crosses, holy water, and other such inventions of religious men. Of course God can make unnatural apparitions. But it is not part of Christian faith that he does this so often that people should fear them more than they fear him stopping or changing the ordinary course of nature, which he can also do. Bad people use God's ability to do anything as an excuse to say anything that suits them, even when they believe it is false. Wise people should believe them only as far as sound reason makes their claims credible. If we removed this superstitious fear of spirits, along with predictions from dreams, false prophecies, and the many related devices by which cunning, ambitious people take advantage of ordinary people, we would be much better prepared for civil obedience.

The schools ought to do this work, but instead they encourage such teachings. Since they do not know what imagination or the senses are, they teach whatever they have received. Some say mental images arise by themselves, without a cause. Others say they usually arise from the will, or that God blows good thoughts into a person and the Devil blows in bad ones, or that God pours in good thoughts and the Devil pours in bad ones. Some say the senses receive the “species” of things and hand them to common sense, which hands them to imagination, which hands them to memory, which hands them to judgment. It is as if they were passing objects from hand to hand. They use many words without making anything clear.

The imagination raised in a human being, or any other creature capable of imagining, by words or other voluntary signs is what we generally call understanding. Human beings and animals both have it. Through habit a dog understands its master's call or scolding, and many other animals do too. The understanding peculiar to human beings concerns not just another person's wishes but that person's ideas and thoughts, expressed by putting the names of things together in affirmations, denials, and other forms of speech. I will speak later about this kind of understanding.

CHAPTER III. OF THE CONSEQUENCE OR TRAIN OF IMAGINATIONS