I really wanted to post this along with the discussion we had several weeks ago on the nature of images, but I can no longer find a good place. Perhaps at some point I can find the right place and insert a link to this post.
For present purposes, of course the topic of images is primarily treated in Book 4 of Lucretius.
The precise purpose of this post, however, is to highlight the second part of Book 4 where Lucretius moves past his initial introduction of images being perceived by the eyes, and returns to images to discuss how they can impact the mind DIRECTLY - meaning, without going through the eyes. This would clearly be relevant to DeWitt's discussion of the mind as a "suprasensory mechanism" that perceives images directly, and of course of relevance to the issue of receiving images of the gods, though that does not seem to be the focus here.
There are many aspects of this that are fascinating, including the place it appears in the text, right after a discussion of lions fearing cocks, and right before he turns to the one of the even more fascinating sections that appears to bear directly on "evolution." For now, however, here is the part on images affecting the mind directly:
Come now, let me tell you what things stir the mind, and learn in a few words whence come the things which come into the understanding. First of all I say this, that many idols of things wander about in many ways in all directions on every side, fine idols, which easily become linked with one another in the air, when they come across one another’s path, like spider’s web and gold leaf. For indeed these idols are far finer in their texture than those which fill the eyes and arouse sight, since these pierce through the pores of the body and awake the fine nature of the mind within, and arouse its sensation. And so we see Centaurs and the limbs of Scyllas, and the dog-faces of Cerberus and idols of those who have met death, and whose bones are held in the embrace of earth; since idols of every kind are borne everywhere, some which are created of their own accord even in the air, some which depart in each case from diverse things, and those again which are made and put together from the shapes of these. For in truth the image of the Centaur comes not from a living thing, since there never was the nature of such a living creature, but when by chance the images of man and horse have met, they cling together readily at once, as we have said ere now, because of their subtle nature and fine fabric. All other things of this kind are fashioned in the same way. And when they move nimbly with exceeding lightness, as I have shown ere now, any one such subtle image stirs their mind; for the mind is fine and of itself wondrous nimble.
That these things come to pass as I tell, you may easily learn from this. Inasmuch as the one is like the other, what we see with the mind, and what we see with the eyes, they must needs be created in like manner. Now, therefore, since I have shown that I see a lion maybe, by means of idols, which severally stir the eyes, we may know that the mind is moved in like manner, in that it sees a lion and all else neither more nor less than the eyes, except that it sees finer idols. And when sleep has relaxed the limbs, the understanding of the mind is for no other cause awake, but that these same idols stir our minds then, as when we are awake, insomuch that we seem surely to behold even one who has quitted life, and is holden by death and the earth. This nature constrains to come to pass just because all the senses of the body are checked and at rest throughout the limbs, nor can they refute the falsehood by true facts. Moreover, the memory lies at rest, and is torpid in slumber, nor does it argue against us that he, whom the understanding believes that it beholds alive, has long ago won to death and doom. For the rest, it is not wonderful that the idols should move and toss their arms and their other limbs in rhythmic time. For it comes to pass that the image in sleep seems to do this; inasmuch as when the first image passes away and then another comes to birth in a different posture, the former seems then to have changed its gesture. And indeed we must suppose that this comes to pass in quick process: so great is the speed, so great the store of things, so great, in any one instant that we can perceive, the abundance of the little parts of images, whereby the supply may be continued.
And in these matters many questions are asked, and there are many things we must make clear, if we wish to set forth the truth plainly. First of all it is asked why, whatever the whim may come to each of us to think of, straightway his mind thinks of that very thing. Do the idols keep watch on our will, and does the image rise up before us, as soon as we desire, whether it pleases us to think of sea or land or sky either? Gatherings of men, a procession, banquets, battles, does nature create all things at a word, and make them ready for us? And that when in the same place and spot the mind of others is thinking of things all far different. What, again, when in sleep we behold idols dancing forward in rhythmic measure, and moving their supple limbs, when alternately they shoot out swiftly their supple arms, and repeat to the eyes a gesture made by the feet in harmony? Idols in sooth are steeped in art and wander about trained to be able to tread their dance in the nighttime. Or will this be nearer truth? Because within a single time, which we perceive, that is, when a single word is uttered, many times lie unnoted, which reasoning discovers, therefore it comes to pass that in any time however small the several idols are there ready at hand in all the several spots. So great is the speed, so great the store of things.
Therefore when the first image passes away and then another comes to birth in a different posture, the former seems then to have changed its gesture. Again, because they are fine, the mind cannot discern them sharply, save those which it strains to see; therefore all that there are besides these pass away, save those for which it has made itself ready. Moreover, the mind makes itself ready, and hopes it will come to pass that it will see what follows upon each several thing; therefore it comes to be. Do you not see the eyes too, when they begin to perceive things which are fine, strain themselves and make themselves ready, and that without that it cannot come to pass that we see things sharply? And yet even in things plain to see you might notice that, if you do not turn your mind to them, it is just as if the thing were sundered from you all the time, and very far away. How then is it strange, if the mind loses all else, save only the things to which it is itself given up? Then too on small signs we base wide opinions, and involve ourselves in the snare of self-deceit.
It happens too that from time to time an image of different kind rises before us, and what was before a woman, seems now to have become a man before our very eyes, or else one face or age follows after another. But that we should not think this strange, sleep and its forgetfulness secure.
Herein you must eagerly desire to shun this fault, and with foresighted fear to avoid this error; do not think that the bright light of the eyes was created in order that we may be able to look before us, or that, in order that we may have power to plant long paces, therefore the tops of shanks and thighs, based upon the feet, are able to bend; or again, that the forearms are jointed to the strong upper arms and hands given us to serve us on either side, in order that we might be able to do what was needful for life. All other ideas of this sort, which men proclaim, by distorted reasoning set effect for cause, since nothing at all was born in the body that we might be able to use it, but what is born creates its own use. Nor did sight exist before the light of the eyes was born, nor pleading in words before the tongue was created, but rather the birth of the tongue came long before discourse, and the ears were created much before sound was heard, and in short all the limbs, I trow, existed before their use came about: they cannot then have grown for the purpose of using them.