Episode Fifty-Three - The Senses Are Never Deceived, Even By Illusions

  • Welcome to Episode Fifty-Three of Lucretius Today. I am your host Cassius, and together with my panelists from the EpicureanFriends.com forum, we'll walk you through the six books of Lucretius' poem, and discuss how Epicurean philosophy can apply to you today. Be aware that none of us are professional philosophers, and everyone here is a self-taught Epicurean. We encourage you to study Epicurus for yourself, and we suggest the best place to start is the book, "Epicurus and His Philosophy" by Canadian professor Norman DeWitt.

    For anyone who is not familiar with our podcast, please check back to Episode One for a discussion of our goals and our ground rules. If you have any question about that, please be sure to contact us at Epicureanfriends.com for more information.

    In today's podcast we will discuss how mistaken judgments caused by illusions should not be considered to be the fault of the senses, but of the mind. Our text will be from Latin Lines: 324- 468. Now let's join Martin reading today's text.

    Munro Notes:

    321-378: this theory of images will explain many other things : you cannot gaze on the sun, because of the force with which images come from it., and the seeds of fire mixed in them : the jaundiced see all things of a greenish yellow, because of the atoms of this colour which proceed from them and meet the images : we see out of the dark things in the light, because a bright clear air, advancing before the images of things in the light, purges the eye of the gross air of darkness, the former air being much more minute and penetrating than the latter: we cannot see what is in the dark, because the gross air comes behind the bright and blocks up the sight against all images: a square tower from a distance looks round, because the images are blunted in their long journey through the air: our shadow seems to follow us and move as we do, because it is really nothing but air without light: one part of the earth after another being shaded from the sun as we advance, and the parts before covered by us left exposed as we leave them.

    379-468: in all this the eyes are not deceived; what they see, they rightly see; it is the mind that errs in the inferences it draws : this applies to thousands of things in which the senses seem to be mistaken; when we are in a ship which is moving, it seems to be at rest, and things which it passes to be in motion; the stars which are in perpetual movement, appear to stand still; if you look clown a long colonnade, the roof and floor and the sides seem at the other end to converge to a point; out at sea the sun appears to rise from the water and to set in it; the parts of a ship under water look bent and twisted upwards; when clouds scud across the sky, the stars seem to move the other way; if you press the eyeball beneath, you see all things double; when fast asleep in a small room in the dark, you often think you see daylight and are travelling over wide distances: in all this the error lies in the opinions which the mind superinduces upon what the senses really perceive.

    Browne 1743

    The eyes, you observe, fly and avoid a glaring object; the sun likewise blinds you if you look too intensely against it, because its force is great, and its images are discharged from above through the pure air, and strike violently upon the eyes, and disturb and loosen their contexture; besides, a brightness too powerful for the sight often burns the eye, because it contains many seeds of fire, which piercing the ball, give it sensible pain. And then, whatever a person looks upon that has the yellow jaundice becomes pale and lurid; because many lurid seeds flow from such a body, and meet with the images of things as they advance. And further, there are many seeds within the eyes of one so distempered which stain all things with their infection and make them look pale. Again, if we are placed in the dark, we see objects that are in the light, because when the dark air, which is nearer, first enters and takes possession of the open eyes, the bright clear air immediately follows, which as it were purges the eye and dissipates the darkness the dusky air has infused into it; for this lucid air is by many degrees more apt to move, is more subtle, and has more force. This, as soon as it has filled the passages of the eyes with light, and opened those pores that the dark air has stopped before, the images of things conveyed in the light immediately follow, and strike upon the eye, and move the sight. But if we are placed in the light, we cannot discover objects in the dark, because a train of dark and thicker air follows the bright, which is nearest the eye, and stops up all the pores, and so chokes up the passages of the sight that the images of things cannot be moved or received into it.

    Further, when we see the square towers of a city at a distance they commonly appear round to us, because all angles, seen far off, show obtuse, or rather they do not show at all. Their strokes die away, and the blows never reach our eyes, for, as the images are carried through a long tract of air, the air beats upon them continually in their passage, and so wears off their corners. Hence it is that since no manner of angle strikes the eye the stony fabric appears of a circular figure; yet the roundness is not so distinct as if the object itself were really round and seen at a small distance, but it bears a kind of resemblance to such a figure, yet is not completely so. Our shadows seem to move with us in the sun, to follow our steps, and imitate our gestures (if you can suppose that air, void of light, is able to walk, and to follow the motions and gestures of the body; for what we usually call shadow can be nothing but the air deprived of light). The reason is because as we walk we hinder the rays of the sun from striking upon a certain part of the earth, which by that means becomes dark; but that as we leave the place it is covered with light, and therefore it is that the shadow of the body over against it follows us in all our motions. For a train of new rays are continually flowing from the sun; and the first dies away like thread of wool drawn through a flame, and by this means that part of the earth is soon deprived of light, and again becomes bright, and discharges the black shade that hung upon it.

    But in this case we are not in the least to allow that the eyes are deceived; it is their business to discover only where the light and shade are, but to determine nothing whether the light be the same, or the shadow be the same that moves from one place to another, or whether it be as we explained above. It is the office of the mind and judgment to distinguish this, for the eyes can know nothing of the nature of things, and therefore you are not to impute to them the failures of the mind. When we are on ship-board, the vessel drives on when it seems to stand still, and when it lies at anchor it seems to move; the hills and plains seem to fly and retire from us as we row, or scour with full sails before the wind. And thus all the stars seem fixed in the vaulted sky, when they are all in continual motion: they rise, and when they have measured the heavens with their bright orbs, they set again at an immense distance. The sun and moon, by the same rule, appear fixed, when experience tells us that they move. And mountains, standing at a distance from one another in the middle of the sea, so that a fleet of ships may sail easily between them, appear like one continued ridge of rocks, and though widely separated, yet show like one vast island, formed by all of them joined together. So boys, when they have made themselves giddy, so strongly fancy that the walls are turned about, and the pillars run round, that even when they stand still, they can scarce believe but that the whole house threatens to tumble upon their heads.

    Thus, when nature begins to display the bright splendor of the sun with trembling light, and to raise it above the top of the mountains, that hill over which the sun just appears, and glowing seems to scorch with his beams, is scarce two thousand bow-shot distant from us, perhaps not five hundred casts of a dart; when yet, between that and the sun lie many mighty seas, spread under a vast expansion of the heavens; many thousand leagues of land lie between, possessed by many nations, and the whole race of wild beasts. So a puddle of water, no deeper than one of your fingers, that lies in the street between the stones, affords a prospect so deep under the earth as the distance between the earth and the wide arch of heaven, so that you seem to look down upon the clouds to take a clear survey of the sky and view with wonder the celestial bodies contained in it, as they seem beneath the earth. Observe, when your mettled horse stands still with you in the middle of a river, and you look down upon the rapid stream of the water, the force of the current seems to drive your horse violently upwards, and hurry you swiftly against the tide; and on which side soever you cast your eyes, all things seem to be borne along, and carried against the current in the same manner.

    A long portico, though it be of equal breadth from one end to the other, and reaches far, supported by pillars of equal height, yet when you stand at one end to take a view of its whole extent, it contracts itself by degrees to a narrow point at the further end; the roof touches the floor, and both sides seem to meet, 'til it terminates at last in the sharp figure of a dark cone. The sun, to Mariners, seems to rise out of the sea, and there again to set and hide his light; for they see nothing but the water and the sky; but therefore you are not to conclude rashly that the senses are at all deceived. To those who know nothing of the sea, a ship in the port seems disabled, and to strive against the waves with broken oars; for that part of the oar and of the rudder that is above the water appears straight, but all below, being refracted, seems to be turned upwards, and to be bent towards the top of the water, and to float almost upon the surface of it. So when the winds drive the light clouds along the sky in the night, the moon and stars seem to fly against the clouds, and to be driven above them in a course quite opposite to that in which they naturally move. And if you chance to press with your fingers under one of your eyes, the effect will be that every thing you look upon will appear double, every bright candle will burn with two flames, and all the furniture of the house will multiply and show double; every face about you, and every body, will look like two. Lastly, when sleep has bound our limbs in sweet repose, and all the body lies dissolved in rest, we think ourselves awake; our members move, and in the gloomy darkness of the night we think we see the sun in broad day-light, and, though confined in bed, we wander over the heavens, the sea, the rivers, and the hills, and fancy we are walking through the plains. And sounds we seem to hear; and, though the tongue be still, we seem to speak, when the deep silence of night reigns all about us. Many more things of this kind we observe and wonder at, which attempt to overthrow the certainty of our senses, but to no purpose - for things of this sort generally deceive us upon account of the judgment of the mind which we apply to them, and so we conclude we see things which we really do not; for nothing is more difficult than to distinguish things clear and plain from such as are doubtful, to which the mind is ready to add its assent, as it is inclined to believe everything imparted by the senses.


    Bright things again the eyes eschew and shun to look upon: the sun even blinds them, if you persist in turning them towards it, because its power is great and idols are borne through the clear air with great downward force from on high, and strike the eyes, and disorder their fastenings. Moreover any vivid brightness often bums the eyes, because it contains many seeds of fire which make a way in and beget pain in the eyes. Again whatever the jaundiced look at becomes a greenish-yellow, because many seeds of greenish-yellow stream from their body and meet the idols of things, and many too are mixed up in their eyes, and these by their infection tinge all things with sallow hues. Again we see out of the dark things which are in the light for this reason: when the black air of darkness being the nearer has first entered and taken possession of the open eyes, the bright white air follows straightway after and cleanses them so to say and dispels the black shadows of the other air; for this is a great deal more nimble, a great deal more subtle and more efficacious. As soon as it has filled with light and opened up the passages of the eyes which the black air had before blocked up, forthwith the idols of things which are situated in the light follow and excite them so that we see. This we cannot do conversely in the dark out of the light, because the grosser air of darkness follows behind and quite fills all the openings and blocks up the passages of the eyes, not letting the idols of any things at all be thrown into the eyes to move them.

    Again when we descry far off the square towers of a town, they often appear to be round for this reason: all the angles are seen from a distance to look obtuse, or rather are not seen at all, and their blow is lost and their stroke never makes its way to our sight, because while the idols are borne on through much air, the air by repeated collisions blunts the stroke perforce. When in this way all the angles have together eluded the sense, the stone structures are rounded off as if by the lathe; yet they do not look like the things which are close before us and really round, but somewhat resembling them as in shadowy outline. Our shadow likewise seems to move in the sunshine and to follow our steps and mimic our action; if you think forsooth that air deprived of life can step, imitating the motions and the actions of men; for that which we are wont to term shadow can be nothing but air devoid of light. Sure enough, because the earth in certain spots successively is deprived of light wherever we intercept it in moving about, while that part of it which we have quitted is filled with light, therefore that which was the shadow of our body, seems to have always followed us unchanged in a direct line with us. For new rays of light ever pour in and the old are lost, just as if wool were drawn into the fire. Therefore the earth is readily stripped of light, and again filled, and cleanses itself from black shadows.

    And yet in all this we do not admit that the eyes are cheated one whit, for it is their province to observe in what spot soever light and shade are; but whether the lights are still the same or not, and whether it is the same shadow which was in this spot that is now passing to that, or whether what we said a little before is not rather the fact, this the reason of the mind, and only it, has to determine; nor can the eyes know the nature of things. Do not then fasten upon the eyes this frailty of the mind. The ship in which we are sailing moves on while seeming to stand still; that one which remains at its moorings is believed to be passing by. The hills and fields seem to be dropping astern, past which we are driving our ship and flying under sail. The stars all seem to be at rest fast fixed to the ethereal vaults, and yet are all in constant motion, since they rise and then go back to their far-off places of setting after they have traversed the length of heaven with their bright bodies. In like manner sun and moon seem to stay in one place, bodies which simple fact proves are carried on. And though between mountains rising up afar off from amid the waters there opens out for fleets a free passage of wide extent, yet a single island seems to be formed out of them united into one. When children have stopped turning round themselves, the halls appear to them to whirl about and the pillars to course round to such a degree, that they can scarce believe that the whole roof is not threatening to tumble down upon them.

    Again when nature begins to raise on high the sun’s beam ruddy with bickering fires and to lift it up above the mountains, those hills above which the sun then seems to you to be, as blazing close at hand he dyes them with his own fire, are distant from us scarce two thousand arrow-flights, yea often scarce five hundred casts of a javelin; and yet between them and the sun lie immense levels of sea, spread out below the huge borders of ether, and many thousands of lands are between, held by divers peoples and races of wild beasts. Then a puddle of water not more than a finger-breadth deep, which stands between the stones in the streets, offers a prospect beneath the earth of a reach as vast, as that with which the high yawning maw of heaven opens out above the earth; so that you seem to discern clouds and see the bodies of birds far withdrawn into that wondrous sky beneath the earth. Again when our stout horse has stuck in the middle of a river and we have looked down on the swift waters of the stream, some force seems to carry athwart the current the body of the horse which is standing still and to force it rapidly up the stream; and to whatever point we cast our eyes about, all things seem to be carried on and to be flowing in the same way as we are.

    Again although a portico runs in parallel lines from one end to the other and stands supported by equal columns along its whole extent, yet when, from the top of it, it is seen in its entire length, it gradually forms the contracted top of a narrowing cone, until uniting roof with floor and all the right side with the left it has brought them together into the vanishing point of a cone. To sailors on the sea the sun appears to rise out of the waters and in the waters to set and bury his light; just because they behold nothing but water and sky; that you may not lightly suppose the credit of the senses to be shaken on all hands. Then to people unacquainted with the sea ships in harbor seem to be all askew and with poop fittings broken to be pressing up against the water. For whatever part of the oars is raised above the saltwater is straight, and the rudders in their upper half are straight: the parts which are sunk below the water-level appear to be broken and bent round and to slope up and turn back towards the surface and to be so much twisted back as well nigh to float on the top of the water. And when the winds carry the thinly scattered clouds across heaven in the night time, then do the glittering signs appear to glide athwart the rack and to be traveling on high in a direction quite different to their real course. Then if our hand chance to be placed beneath one eye and press it below, through a certain sensation all things which we look at appear then to become double as we look; the light of lamps brilliant with flames to be double, double too the furniture through the whole house, double men’s faces and men’s bodies. Again when sleep has chained down our limbs in sweet slumber and the whole body is sunk in profound repose, yet then we seem to ourselves to be awake and to be moving our limbs, and mid the thick darkness of night we think we see the sun and the daylight; and though in a confined room, we seem to be passing to new climates seas rivers and mountains and to be crossing plains on foot and to hear noises, though the austere silence of night prevails all round, and to be uttering speech though quite silent. Many are the other marvels of this sort we see, which all seek to shake as it were the credit of the senses: quite in vain, since the greatest part of these cases cheats us on account of the mental suppositions which we add of ourselves, taking those things as seen which have not been seen by the senses. For nothing is harder than to separate manifest facts from doubtful which straightway the mind adds on of itself.


    Bright things moreover the eyes avoid, and shun to look upon. The sun, too, blinds, if you try to raise your eyes to meet him, because his own power is great, and the idols from him are borne through the clear air, sinking heavily into the deep, and strike upon the eyes, disordering their texture. Moreover, any piercing brightness often burns the eyes for the reason that it contains many seeds of fire, which give birth to pain in the eyes, finding their way in. Moreover, whatever the jaundiced look upon becomes sickly-yellow, because many seeds of yellow stream off from their bodies to meet the idols of things, and many also are mixed in their eyes, which by their infection tinge all things with their pallor. Now we see things that are in the light out of the darkness, because, when the black air of the gloom, which is nearer, first enters and seizes on the open eyes, there follows in hot haste a bright air full of light, which, as it were, cleanses the eyes and scatters abroad the dark shadows of the former air. For the latter is many times more nimble, many times finer and more potent. And as soon as it has filled the passages of the eyes with light, and opened up those which before the black air had beleaguered, straightway follow the idols of the things which are lying in the light, and excite our eyes so that we see. But, on the other hand, we cannot do this in the darkness out of the light, because the air of the gloom, which is denser, comes on afterwards, and fills all the channels and beleaguers the passages of the eyes, so that none of the idols of things can be cast upon them and stir them.

    And when we see from afar off the square towers of a town, it comes to pass for this cause that they often look round, because every angle from a distance is seen flattened, or rather it is not seen at all, and the blow from it passes away, nor does its stroke come home to our eyes, because, while the idols are being borne on through much air, the air by its frequent collisions constrains it to become blunted. When for this cause every angle alike has escaped our sense, it comes to pass that the structures of stone are worn away as though turned on the lathe; yet they do not look like things which are really round to a near view, but a little resembling them as though in shadowy shape. Likewise our shadow seems to us to move in the sunshine, and to follow our footsteps and imitate our gait; if indeed you believe that air bereft of light can step forward, following the movements and gait of men. For that which we are wont to name a shadow can be nothing else but air devoid of light. But in very truth it is because in certain spots in due order the ground is bereft of the light of the sun wherever we, as we move on, cut it off, and likewise the part of it which we have left is filled again; for this cause it comes to pass that, what was but now the shadow of our body, seems always to follow unaltered straight along with us. For always new rays of light are pouring out, and the former perish, like wool drawn into a flame. Therefore readily is the ground robbed of light, and is likewise filled again and washes away its own black shadows.

    And yet we do not grant that in this the eyes are a whit deceived. For it is theirs to see in what several spots there is light and shade: but whether it is the same light or not, whether it is the same shadow which was here, that now passes there, or whether that rather comes to pass which I said a little before, this the reasoning of the mind alone must needs determine, nor can the eyes know the nature of things. Do not then be prone to fasten on the eyes this fault in the mind. The ship, in which we journey, is borne along, when it seems to be standing still; another, which remains at anchor, is thought to be passing by. The hills and plains seem to be flying towards the stern, past which we are driving on our ship with skimming sail. All the stars, fast set in the vault of the firmament, seem to be still, and yet they are all in ceaseless motion, inasmuch as they rise and return again to their distant settings, when they have traversed the heaven with their bright body. And in like manner sun and moon seem to abide in their places, yet actual fact shows that they are borne on. And mountains rising up afar off from the middle of the waters, between which there is a free wide issue for ships, yet seem united to make a single island.

    When children have ceased turning round themselves, so sure does it come to appear to them that the halls are turning about, and the pillars racing round, that scarcely now can they believe that the whole roof is not threatening to fall in upon them. And again, when nature begins to raise on high the sunbeam ruddy with twinkling fires, and to lift it above the mountains, those mountains above which the sun seems to you to stand, as he touches them with his own fire, all aglow close at hand, are scarce distant from us two thousand flights of an arrow, nay often scarce five hundred casts of a javelin: but between them and the sun lie the vast levels of ocean, strewn beneath the wide coasts of heaven, and many thousands of lands are set between, which diverse races inhabit, and tribes of wild beasts. And yet a pool of water not deeper than a single finger-breadth, which lies between the stones on the paved street, affords us a view beneath the earth to a depth as vast as the high gaping mouth of heaven stretches above the earth; so that you seem to descry the clouds and the heaven and bodies wise hidden beneath the earth—yet in a magic sky. Again, when our eager horse has stuck fast amid a river, and we look down into the hurrying waters of the stream, the force seems to be carrying on the body of the horse, though he stands still, athwart the current, and to be thrusting it in hot haste up the stream; and wherever we cast our eyes all things seem to be borne on and flowing forward, as we are ourselves.

    Though a colonnade runs on straight-set lines all the way, and stands resting on equal columns from end to end, yet when its whole length is seen from the top end, little by little it contracts to the pointed head of a narrow cone, joining roof with floor, and all the right hand with the left, until it has brought all together into the point of a cone that passes out of sight. It happens to sailors on the sea that the sun seems to rise from the waves, and again to set in the waves, and hide its light; since verily they behold nothing else but water and sky; so that you must not lightly think that the senses waver at every point. But to those who know not the sea, ships in the harbour seem to press upon the water maimed, and with broken poop. For all the part of the oars which is raised up above the salt sea spray, is straight, and the rudders are straight above; but all that is sunk beneath the water, seems to be broken back and turned round, yes, and to turn upwards again and twist back so that it almost floats on the water’s surface. And when winds in the night season carry scattered clouds across the sky, then the shining signs seem to glide athwart the storm-clouds, and to be moving on high in a direction far different from their true course. Then if by chance a hand be placed beneath one eye and press it, it comes to pass by a new kind of perception that all things which we look at seem to become double as we look, double the lights of the lamps with their flowery flames, double the furniture throughout the whole house in twin sets, and double the faces of men, double their bodies. Again, when sleep has bound our limbs in sweet slumber, and all the body lies in complete rest, yet then we seem to ourselves to be awake and moving our limbs, and in the blind gloom of night we think to see the sun and the light of day, and, though in some walled room, we seem to pass to new sky, new sea, new streams, and mountains, and on foot to cross over plains, and to hear sounds, when the stern silence of night is set all about us, and to give answer, when we do not speak. Wondrously many other things of this sort we see, all of which would fain spoil our trust in the senses; all in vain, since the greatest part of these things deceives us on account of the opinions of the mind, which we add ourselves, so that things not seen by the senses are counted as seen. For nothing is harder than to distinguish things manifest from things uncertain, which the mind straightway adds of itself.

  • Episode Fifty-Three of the Lucretius Today Podcast is now available. In today's podcast we will discuss how mistaken judgments caused by illusions should not be considered to be the fault of the senses, but of the mind. Our text will be from Latin Lines: 324- 468. Thanks to Martin for reading today's text.

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  • Cassius

    Changed the title of the thread from “Episode Fifty-Three - The Senses Are Never Deceived, Even By Illusions [Pre-Production]” to “Episode Fifty-Three - The Senses Are Never Deceived, Even By Illusions”.