so successively one part beateth back the other to the very eye; and in the same manner the exterior part of the eye (the laws of refraction still observed) presseth the interior. Now the interior coat of the eye is nothing else but a piece of the optic nerve, and therefore the motion is still continued thereby into the brain, and by resistance or reaction of the brain, is also a rebound in the optic nerve again, which we not conceiving as motion or rebound from within, think it is without, and call it light; as hath been already shewed by the experience of a stroke. We have no reason to doubt, that the fountain of light, the sun, worketh any other wise than the fire, at least in this matter, and thus all vision hath its original from such motion as is here described. For where there is no light, there is no sight; and therefore colour also must be the same thing with light, as being the effect of lucid bodies: their difference being only this, that when the light cometh directly from the fountain to the eye, or indirectly by reflection from clean and polite bodies, and such as have no particular motion internal to alter it, we call it light. But when it cometh to the eyes by reflection from uneven, rough, and coarse bodies, or such as are affected with internal motion of their own, that may alter it, then we call it colour; colour and light differing only in this, that the one is pure, the other a perturbed light. By that which hath been said, not only the truth of the third proposition, but also the whole manner of producing light and colour, is apparent.
9. As colour is not inherent in the object, but an effect thereof upon us, caused by such motion in the object, as hath been described: so neither is sound in the thing we hear, but in ourselves. One manifest sign thereof is: that as a man may see, so also he may hear double or treble, by multiplication of echoes, which echoes are sounds as well as the original; and not being in one and the same place, cannot be inherent in the body that maketh them. Nothing can make any thing in itself: the clapper hath not sound in it, but motion, and maketh motion in the internal parts of the bell so the bell hath motion, and not sound. That imparteth motion to the air; and the air hath motion, but not sound. The air imparteth motion by the ear and nerves to the brain; and the brain hath motion but not sound. From the brain it reboundeth back into the nerves outward, and thence it becometh an apparition without, which we call sound. And to proceed to the rest of the senses, it is apparent enough, that the smell and taste of the same thing, are not the same to every man, and therefore are not in the thing smelt or tasted, but in the men. So likewise the heat we feel from the fire is manifestly in us, and is quite different from the heat that is in the fire. For our heat is pleasure or pain, according as it is extreme or moderate; but in the coal there is no such thing. By this the fourth and last of the propositions is proved (viz.) That as in conception by vision, so also in the conceptions that arise from other senses, the subject of their inherence is not the object, but the sentient.
10. And from thence also it followeth, that whatsoever accidents or qualities our senses make us think there be in the world, they are not there, but are seemings and apparitions only. The things that really are in the world without us, are those motions by which these seemings are caused. And this is the great deception of sense, which also is by sense to be corrected. For as sense telleth me, when I see directly, that the colour seemeth to be in the object; so also sense telleth me, when I see by reflection, that colour is not in the object.
Chapter 3: Of Imagination and the Kinds Thereof
1. As standing water put into motion by the stroke of a stone, or blast of wind, doth not presently give over moving as soon as the wind ceaseth, or the stone settleth: so neither doth the effect cease which the object hath wrought upon the brain, so soon as ever by turning aside of the organ the object ceaseth to work; that is to say, though the sense be past, the image or conception remaineth; but more obscurely while we are awake, because some object or other continually plieth and soliciteth our eyes, and ears, keeping the mind in a stronger motion, whereby the weaker doth not easily appear. And this obscure conception is that we call PHANTASY or IMAGINATION: imagination being (to define it) conception remaining, and by little and little decaying from and after the act of sense.
2. But when present sense is not, as in SLEEP, there the images remaining after sense (when there be any) as in dreams, are not obscure, but strong and clear, as in sense itself. The reason IS, because that which obscured and made the conceptions weak, namely sense, and present operation of the objects, is removed. For sleep is the privation of the act of sense, (the power remaining) and dreams are the imaginations of them that sleep.
3. The causes of DREAMS (if they be natural) are the actions or violence of the inward parts of a man upon his brain, by which the passages of sense, by sleep benumbed, are restored to their motion. The signs by which this appeareth to be so, are the differences of dreams proceeding from the different accidents of man's body. Old men being commonly less healthful and less free from inward pains, are thereby more subject to dreams, especially such dreams as be painful: as dreams of lust, or dreams of anger, according as the heart, or other parts within, work more or less upon the brain, by more or less heat. So also the descent of different sorts of phlegm maketh one to dream of different tastes of meats or drinks. And I believe there is a reciprocation of motion from the brain to the vital parts, and back from the vital parts to the brain; whereby not only imagination begetteth motion in those parts; but also motion in those parts begetteth imagination like to that by which it was begotten. If this be true, and that sad imaginations nourish the spleen, then we see also a cause, why a strong spleen reciprocally causeth fearful dreams. And why the effects of lasciviousness may in a dream produce the image of some person that hath caused them. If it were well observed, whether the image of the person in a dream be as obedient to the accidental heat of him that dreameth, as waking his heat is to the person, and if so, then is such motion reciprocal. Another sign that dreams are caused by the action of the inward parts, is the disorder and casual consequence of one conception or image to another: for when we are waking, the antecedent thought or conception introduceth, and is cause of the consequent, as the water followeth a man's finger upon a dry and level table. But in dreams there is commonly no coherence (and when there is, it is by chance), which must proceed from this, that the brain in dreams is not restored to its motion in every part alike; whereby it cometh to pass, that our thoughts appear like the stars between the flying clouds, not in the order which a man would choose to observe them in, but as the uncertain flight of broken clouds permit.
4. As when the water, or any liquid thing moved at once by divers movements, receiveth one motion compounded of them all; so also the brain or spirits therein, having been stirred by divers objects, composeth an imagination of divers conceptions that appeared. singly to the sense. As for example, the sense sheweth us at one time the figure of a mountain, and at another time the colour of gold; but the imagination afterwards hath them both at once in a golden mountain. From the same cause it is, there appear unto us castles in the air, chimeras, and other monsters which are not in rerum natura, but have been conceived by the sense in pieces at several times. And this composition is that which we commonly call FICTION of the mind.
5. There is yet another kind of. imagination, which for clearness contendeth with sense, as well as a dream; and that is, when the action of sense hath been long or vehement: and the experience thereof is more frequent in the sense of seeing, than the rest. An example whereof is, the image remaining before the eye after a steadfast looking upon the sun. Also, those little images that appear before the eyes in the dark (whereof I think every man hath experience, but they most of all, that are timorous or superstitious) are examples of the same. And these, for distinction sake, may be called PHANTASMS.
6. By the senses (which are numbered according to the organs to be five) we take notice (as hath been said already) of the objects without us; and that notice is our conception thereof: but we take notice also some way or other of our conceptions. For when the conception of the same thing cometh again, we take notice that it is again; that is to say, that we have had the same conception before; which is as much as to imagine a thing past; which is impossible to sense, which is only of things present. This therefore may be accounted a
