Lucretius Today Podcast Episode 053 – The Senses Are Never Deceived, Even By Illusions

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Episode 53 of the Lucretius Today Podcast is now available. This week we discuss the issue of illusions, and how it is never the senses that are deceived, but instead our judgment. The senses remain the foundation of all our engagement with the world around us, and we learn to take illusions into account and correct them – not by reason alone – but by additional observations. As always, please feel free to ask any questions or discuss the podcast here, and remember to subscribe on your favorite podcasting application.

Welcome to Episode Fifty-Three of Lucretius Today. I am your host Cassius, and together with my panelists from the 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 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.

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.