‘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, hears, &c. 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 is therefore nothing but decaying sense; and is found in man and many other living creatures, as well sleeping as waking.
‘The decay of sense in men waking is 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 follows, that the longer the time is, after the sight or sense of any objects the weaker is the imagination. For the continual change of man’s 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 conceives himself a Hercules or an Alexander (which happeneth often to them which are much taken with the reading of Romaunts) it is a compound imagination, and properly but a fiction of the mind.
‘There be also other imaginations that rise in man, (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 image 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 men’s discourse.
‘The imaginations of them that sleep are those we call dreams: and these also (as all other imaginations) have been before, either totally or by parcels in the sense, and because 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 man’s body; which inward parts, for the connexion 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 are 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, subjects, 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.’—Leviathan, pp. 4, 5, 6.
The concluding paragraph of this Chapter is remarkable.
‘The imagination that is raised in man (or any other creature endued 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 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.’—Page 8.
As in the first two chapters Mr. Hobbes endeavours to show that all our thoughts, considered singly or in themselves, have their origin in sensation, so in the next chapter, he resolves all their combinations or connexions one with another into the principle of association, or the coexistence of their sensible impressions.
‘By consequence or train of thoughts,’ he says, ‘I understand that succession of one thought to another, which is called (to distinguish it from discourse in words) mental discourse.’
‘When a man thinketh on any thing whatsoever, his next thought after it is not altogether so casual as it seems to be. Not every thought to every thought succeeds indifferently. But as we have no imagination, whereof we have not formerly had sense in whole or in parts; so we have no transition from one imagination to another, whereof we never had the like before in our senses. The reason whereof is this. All fancies are motions within us, reliques of those made in sense: and those motions that succeeded one another in the sense, continue also together after sense: insomuch as the former coming again to take place, and be predominant, the latter followeth, by coherence of the matter moved, in such manner, as water upon a plane table is drawn which way any one part of it is guided by the finger. But because in sense to one and the same thing perceived, sometimes one thing, sometimes another succeedeth, it comes to pass in time, that in the imagining of any thing, there is no certainty what we shall imagine next. Only this is certain, it shall be something that succeeded the same before, at one time or another.’—Page 9.