Thomas Hobbes (15881679). Of Man, Being the First Part of Leviathan. The Harvard Classics. 190914.
THAT when a thing lies still, unless somewhat else stir it, it will lie still for ever, is a truth that no man doubts of. But that when a thing is in motion, it will eternally be in motion, unless somewhat else stay it, though the reason be the same, namely that nothing can change itself, is not so easily assented to. For men measure not only other men but all other things, by themselves; and, because they find themselves subject after motion to pain and lassitude, think everything else grows weary of motion, and seeks repose of its own accord; little considering whether it be not some other motion wherein that desire of rest they find in themselves consisteth. From hence it is that the schools say heavy bodies fall downwards out of an appetite to rest, and to conserve their nature in that place which is most proper for them; ascribing appetite and knowledge of what is good for their conservation, which is more than man has, to things inanimate, absurdly.
When a body is once in motion, it moveth, unless something else hinder it, eternally; and whatsoever hindereth it cannot in an instant, but in time and by degrees, quite extinguish it; and, as we see in the water though the wind cease the waves give not over rolling for a long time after: so also it happeneth in that motion which is made in the internal parts of a man, then, when he sees, dreams, etc. For, after the object is removed, or the eye shut, we still retain an image of the thing seen, though more obscure than when we see it. And this is it the Latins call imagination, from the image made in seeing; and apply the same, though improperly, to all the other senses. But the Greeks call it fancy, which signifies appearance, and is as proper to one sense as to another. Imagination, therefore, is nothing but decaying sense, and is found in men, and many other living creatures, as well sleeping as waking.
The decay of sense in men waking is not the decay of the motion made in sense, but an obscuring of it in such manner as the light of the sun obscureth the light of the stars, which stars do no less exercise their virtue, by which they are visible, in the day than in the night. But because amongst many strokes which our eyes, ears, and other organs, receive from external bodies, the predominant only is sensible; therefore, the light of the sun being predominant, we are not affected with the action of the stars. And any object being removed from our eyes, though the impression it made in us remain, yet other objects more present succeeding and working on us, the imagination of the past is obscured, and made weak, as the voice of a man is in the noise of the day. From whence it followeth that the longer the time is, after the sight or sense of any object, the weaker is the imagination. For the continual change of mans body destroys in time the parts which in sense were moved; so that distance of time, and of place, hath one and the same effect in us. For as at a great distance of place that which we look at appears dim and without distinction of the smaller parts, and as voices grow weak and inarticulate, so also after great distance of time our imagination of the past is weak; and we lose, for example, of cities we have seen many particular streets, and of actions many particular circumstances. This decaying sense, when we would express the thing itself, I mean fancy itself, we call imagination, as I said before; but when we would express the decay, and signify that the sense is fading, old, and past, it is called memory. So that imagination and memory are but one thing, which for divers considerations hath divers names.
Much memory, or memory of many things, is called experience. Again, imagination being only of those things which have been formerly perceived by sense, either all at once or by parts at several times, the former, which is the imagining the whole object as it was presented to the sense, is simple imagination, as when one imagineth a man, or horse, which he hath seen before. The other is compounded, as when, from the sight of a man at one time, and of a horse at another, we conceive in our mind a Centaur. So when a man compoundeth the image of his own person with the image of the actions of another man, as when a man images himself a Hercules or an Alexander, which happeneth often to them that are much taken with reading of romances, it is a compound imagination, and properly but a fiction of the mind. There be also other imaginations that rise in men, though waking, from the great impression made in sense; as, from gazing upon the sun, the impression leaves an image of the sun before our eyes a long time after; and, from being long and vehemently attent upon geometrical figures, a man shall in the dark, though awake, have the images of lines and angles before his eyes; which kind of fancy hath no particular name, as being a thing that doth not commonly fall into mens discourse.
The imaginations of them that sleep are those we call dreams. And these also, as also all other imaginations, have been before, either totally or by parcels, in the sense. And, because in sense, the brain and nerves, which are the necessary organs of sense, are so benumbed in sleep as not easily to be moved by the action of external objects, there can happen in sleep no imagination, and therefore no dream, but what proceeds from the agitation of the inward parts of mans body; which inward parts, for the connection they have with the brain and other organs, when they be distempered, do keep the same in motion; whereby the imaginations there formerly made, appear as if a man were waking; saving that the organs of sense being now benumbed, so as there is no new object which can master and obscure them with a more vigorous impression, a dream must needs be more clear in this silence of sense than our waking thoughts. And hence it cometh to pass that it is a hard matter, and by many thought impossible, to distinguish exactly between sense and dreaming. For my part, when I consider that in dreams I do not often nor constantly think of the same persons, places, objects, and actions, that I do waking, nor remember so long a train of coherent thoughts, dreaming, as at other times, and because waking I often observe the absurdity of dreams, but never dream of the absurdities of my waking thoughts, I am well satisfied, that, being awake, I know I dream not, though when I dream I think myself awake.
And, seeing dreams are caused by the distemper of some of the inward parts of the body, divers distempers must needs cause different dreams. And hence it is that lying cold breedeth dreams of fear, and raiseth the thought and image of some fearful object, the motion from the brain to the inner parts and from the inner parts to the brain being reciprocal; and that, as anger causeth heat in some parts of the body when we are awake, so when we sleep the overheating of the same parts causeth anger, and raiseth up in the brain the imagination of an enemy. In the same manner, as natural kindness, when we are awake, causeth desire, and desire makes heat in certain other parts of the body; so also too much heat in those parts, while we sleep, raiseth in the brain an imagination of some kindness shown. In sum, our dreams are the reverse of our waking imaginations, the motion when we are awake beginning at one end, and when we dream at another.
The most difficult discerning of a mans dream from his waking thoughts is, then, when by some accident we observe not that we have slept: which is easy to happen to a man full of fearful thoughts, and whose conscience is much troubled, and that sleepeth without the circumstances of going to bed or putting off his clothes, as one that noddeth in a chair. For he that taketh pains, and industriously lays himself to sleep, in case any uncouth and exorbitant fancy come unto him, cannot easily think it other than a dream. We read of Marcus Brutus (one that had his life given him by Julius Cæsar, and was also his favorite, and notwithstanding murdered him) how at Philippi, the night before he gave battle to Augustus Cæsar, he saw a fearful apparition, which is commonly related by historians as a vision; but, considering the circumstances, one may easily judge to have been but a short dream. For, sitting in his tent, pensive and troubled with the horror of his rash act, it was not hard for him, slumbering in the cold, to dream of that which most affrighted him; which fear, as by degrees it made him wake, so also it must needs make the apparition by degrees to vanish; and, having no assurance that he slept, he could have no cause to think it a dream or anything but a vision. And this is no very rare accident; for even they that be perfectly awake, if they be timorous and superstitious, possessed with fearful tales, and alone in the dark, are subject to the like fancies, and believe they see spirits and dead mens ghosts walking in churchyards; whereas it is either their fancy only, or else the knavery of such persons as make use of such superstitious fear to pass disguised in the night to places they would not be known to haunt.
From this ignorance of how to distinguish dreams and other strong fancies from vision and sense, did arise the greatest part of the religion of the Gentiles in time past that worshipped satyrs, fawns, nymphs, and the like; and now-a-days the opinion that rude people have of fairies, ghosts, and goblins, and of the power of witches. For as for witches, I think not that their witchcraft is any real power; but yet that they are justly punished for the false belief they have that they can do such mischief, joined with their purpose to do it if they can; their trade being nearer to a new religion than to a craft or science. And for fairies and walking ghosts, the opinion of them has, I think, been on purpose either taught, or not confuted, to keep in credit the use of exorcism, of crosses, of holy water, and other such inventions of ghostly men. Nevertheless there is no doubt but God can make unnatural apparitions,; but that He does it so often as men need to fear such things more than they fear the stay or change of the course of nature, which He also can stay and change, is no point of Christian faith. But evil men, under pretext that God can do anything, are so bold as to say anything when it serves their turn, though they think it untrue; it is the part of a wise man to believe them no farther than right reason makes that which they say appear credible. If this superstitious fear of spirits were taken away, and with it prognostics from dreams, false prophecies, and many other things depending thereon, by which crafty ambitious persons abuse the simple people, men would be much more fitted than they are for civil obedience.
And this ought to be the work of the schools; but they rather nourish such doctrine. For, not knowing what imagination or the senses are, what they receive they teach; some saying that imaginations rise of themselves and have no cause; others that they rise most commonly from the will, and that good thoughts are blown (inspired) into a man by God, and evil thoughts by the devil; or that good thoughts are poured (infused) into a man by God, and evil ones by the devil. Some say the senses receive the species of things, and deliver them to the common sense, and the common sense delivers them over to the fancy, and the fancy to the memory, and the memory to the judgment, like handling of things from one to another, with many words making nothing understood.
The imagination that is raised in man, or any other creature indued with the faculty of imagining, by words or other voluntary signs, is that we generally call understanding, and is common to man and beast. For a dog by custom will understand the call or the rating of his master; and so will many other beasts. That understanding which is peculiar to man is the understanding not only his will but his conceptions and thoughts, by the sequel and contexture of the names of things into affirmations, negations, and other forms of speech; and of this kind of understanding I shall speak hereafter.