Week 12b: Wednesday Readings on Bacon, Prosdocimo, Alberti, Leonardo, and Kepler

Please comment on the variety of readings for Wednesday.  Suggestions include camera obscura, the theology of vision, art and vision, and the retinal image, but there are tons of potential topics in this stuff. Feel free to connect the issues from these readings to issues from past readings.

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16 thoughts on “Week 12b: Wednesday Readings on Bacon, Prosdocimo, Alberti, Leonardo, and Kepler

  1. I was particularly drawn into the Roger Bacon reading on Mathematics and Light and Experimentation because of the intersection of soul, perception, the divine, and the natural. Endeavoring to explain natural phenomena, Bacon employs experimentation and keen observations on the nature of lenses and mirrors. However, in his explanation of sight and vision, he seems to diverge from his original form of rationality of conclusions made from observations, to the use of the divine in nature to explain what he couldn’t explain rationally. Reaching back to metaphysical thought from Aristotle and Boethius, Bacon spins a new web of explanations of how the human soul, perception, and anatomical symmetry, lead to the phenomena of sight. However, it almost seems in his analysis of breaking down how one “sees” into a threefold process mirrors the trinity (I may be reaching here). For example, “direct” could be the corporeal act of seeing (son), “refracted” could be the soul’s (divine or human) ability to influence sight (holy spirit) and “reflected” could be the sense of internally referring (thinking) what you perceive to the divine (which has created everything) and recognizing its omnipotence. This could also apply to Bacon’s idea of sense, memory and reason.

    • Your numerological observations seem right on target to me. I love how this echos Ibn Tufayl’s view of humanity, as a bunch of mirrors reflecting God… some are dirty, some are turned away.. but some are perfectly aligned and polished. Echo the Prophet.

  2. da Vinci’s inclusion of the concept of time in terms of optics was interesting to me. He argues that there is no way visual rays emanate from our eyes, as there would be a lag between when the ray leaves our eye and when it meets the object we are seeing. He uses the sun as his example. I also liked his example of the two mirrors that face each other and how the images in the mirrors go on endlessly. He uses this to show that each object exists as a whole in other objects as well. He also uses the example of the stone being thrown into a body of water to describe the infinite existence of objects in the atmosphere. What link does this have with optics? What is the whole and parts of the whole he keeps referring to? I also liked his idea of why objects become blurry to us when they are too close to our eye. He says it is because the central line of vision is unable to discern the edges of the object. When I tried to do this by placing my hand close to my eye, it seemed rather that my entire hand was blurry rather than just the edges. I understand the theory behind what da Vinci was saying, however. The idea of having one powerful line of vision that came from the center and was the most effective seemed to have been a useful idea in explaining optics and perspective.

    • The ripples in water sounds a lot like Lucretius and his visual films.
      Nice pick-up on the blurry concepts in Leonardo. Few of these pre-Keplerian authors describe out-of-focus very clearly, but Leonardo is quite clear in his description of a lack of clarity.

  3. From the Bacon reading, I was struck by the link between vision and the divine. Bacon writes ‘Just as we see nothing corporeally without corporeal light, so it is impossible for us to see anything spiritually without the spiritual light of the divine grace.’ He goes on to say though that this divine vision isn’t simply a result of what we see, but is informed by memory and by reason, and therefore it isn’t really the physical act of seeing that is divine, but the action of our reason on our vision that makes it so. It is interesting then that it isn’t so much the physical act of seeing that is interesting to Bacon here, but the way we interpret what we see.

    • Isn’t that a beautiful line….
      It is so NeoPlatonic!
      The whole memory and reason part is fascinating. Who gives us reason? From whence does our intellect derive its power? There is still so much Aristotle in all of this… along with religion, and Plato, and the Islamic guys…. Bacon is an amalgam of everything.

  4. With a lot of these readings I noticed a connection with the eye as a sort of gateway to the soul. I know in film theory, characters that are “bad” are not filmed with a reflection of light on their eye. Or in The Blade Runner, androids have a little red glare that gets reflected in their eye. There seems to be some sort of timeless fascination with reflections in eyes as some sort of humanizing trait. Maybe they are reflecting God’s light like in the Ibn Tufayl reading. I though there was a definite connection betweem threefold vision and Hayy’s vision of mirror’s reflecting the divine.
    Also, the reading on Alberti made me think of a couple of paintings. One is Las Meninas by Diego Velasquez. In this painting, Velasquez puts the viewer in a perspectivally impossible position. It is difficult to trace the vanishing point, but it does not lead where one originally suspects. Also, The Ambassadors by Hans Holbein plays with the mathematic perspective. He paints an unidentifiable object across the floor of the painting. If you view the painting from a side angle, the object reveals itself as a properly proportioned human skull.

    Here are the links to look at the paintings if anyone is interested.
    Las Meninas:
    http://jssgallery.org/other_artists/Velazquez/meninas.jpg
    The Ambassadors:
    http://static.guim.co.uk/sys-images/Observer/Columnist/Columnists/2012/9/7/1347019225211/The-Ambassadors-by-Hans-H-001.jpg

  5. I also was interested by the concept of ‘spiritual vision’ in the Bacon reading. Bacon emphasized a connection between the divine and visiion and the necessity of the spiritual existence, maybe the soul, for one to actually see. I started to get confused as what he really meant by this and what kind of seeing he was referring to? Was it actually physically seeing or was it the other components he talked about in terms of seeing, and understanding. Such as seeing with a brain and or seeing without a brain (although seeing without a brain would not be possible, technically) Is the soul or divine spirit he talks about in connection to vision just referring to the mind? I guess that then brings up the whole question of what is the soul. But all in all I found it interested that he is aware of the fact that there is more to vision than just seeing.

    • Good question, on the soul vs. mind. Anima vs. animus in Latin. But this patent dichotomy simplifies it too much. Recall that we are juggling a bunch of terms now: soul, spirit, pneuma, form, species, intention, mind, and probably several more… color, for one.
      Indeed. Seeing is not perceiving. We must make sense of what we see. If in doubt, bring in the spirit. (Spirit seems to function like the ether. If in doubt in the macrocosm… call in the ether. If in doubt in the microcosm.. call in the spirit/pneuma.)

  6. Newsome article address Alberti’s understanding of God as a geometer, a mathematic planner. Michelangelo approached his architectural concepts in much the same way, without ground perspective, because according to him, spaces are meant to be experienced in motion through them. This, he compared to the human body (A branch of God’s design) in its functions, not necessarily the individual body parts.

    It was interesting reading about the straight lines in which Alberti assumes our vision to function. This lead me back to the discussion we had in class Monday about the “glacial humor” and its rays that accept only one perpendicular ray being emitted by single points on an object, making me feel like this argument from class has more to do with reality than I was giving it credit for.

    I think I was struck most by the final quote “In a painting we call a point that small inscription than which nothing can be smaller.” I’m glad that Alberti DOES define a point within the boundaries of painting, for here it almost makes sense, but I’d really like to talk about this idea of a “point” and how absolutely I don’t think it exists. It is an abstracted idea that we use as reference, much like the idea of infinity.

    • Nice tie-in to Michelangelo and architecture and motion and proportion and the macro-microcosm harmony/dance.
      This medieval optical theory is really quite astounding. It takes so little to make it modern.
      Infinite and infinitesimal. The all and more and the mathematical point. I also found it interesting that Alberti was careful to distinguish the physical point in a painting from a real point in Plato’s form-land.

  7. There were several things I found interesting in the Bacon reading. First, Bacon wrote that vision is processed in the anterior part of the brain which is responsible for “common sense and imagination.” As the anterior part of our brain is responsible for abstract thought and decision making, this is not so far off. How did Bacon come to this conclusion? Was it already a popular notion that different parts of the brain were responsible for different parts of the personality and physiology?

    Also, I found it funny that Bacon ended a chapter so focused on religion with the line “…so that every deceit of jesters may be dimmed by the beauty of the wonders of science, and men may rejoice in the truth, banishing far from them the tricks of magicians.” I think this is a really beautiful line, but it begs the question: what exactly did Bacon think he was doing then in relating the aspects of vision he did not fully understand (or believe he understood) to religion? Was he not doing just what he was denouncing?

    • Your question about brain function and topology is a great one. Unfortunately I simply don’t know. Might be a good paper here.
      Your last observation is also quite interesting. I’d start to answer it by suggesting that religion, for Bacon, was beyond reproach. It was the truth and any science had to be verified through religion,… not vice versa. We probably tend to see it the other way around.
      He is also reenforcing God’s power and ultimate wisdom by making it clear that any trickery done by jesters and magicians is always within the boundaries of nature. Science explains their trickery.. the science is what is wonderful. These charlatans are just using science to fool people into thinking that they are somehow above nature. But only God is above nature. He is truly supernatural. Stuart Clark, who writes on premodern magic and such, would call this trickery, at best, preternatural.

  8. I was reading David Byrne’s blog a few years ago and stumbled across these guys, and now can’t think about perspective/perception without thinking about them: Ryan and Trevor Oakes. They’re twin artists, and they have made some pretty astounding claims regarding visual perception, ranging from the slightly comical to the profound. For instance, that we actually see our noses and our eyebrows all the time. After noticing that when you cover one eye you can see your nose poking out at the bottom corner of your visual field, they deduced that we must be able to see our noses all the time and that the brain just ignores this information. Why? Because we have binocular vision, what we see with our right eye overlaps with what we see with our left eye. So if your nose is obscuring a section of your right eye’s visual field, your brain will fill that section in with information from the left eye, where the information is unobstructed. The same goes for eyebrows. They also realized that, though we have a pretty wide visual field, “depth perception is limited to that which both eyes can see.”

    But their most exciting claim (to me, anyway) is that our visual field isn’t flat but spherical. This seems obvious once you think about it for a little bit (our eyeballs are spherical after all — unless you have an astigmatism, like me, which I’m told means my eyes are shaped like footballs; “hypermetropia” according to the Kepler reading, I guess) but the twins have actually put this idea to work. The twins designed a vision machine to solve the problem of how to draw on the inside of a sphere. Essentially, this device reverses the topographical technique of mapping a spherical object onto a grid, instead taking the traditional grid and warping it into a concave grid that would slice up the visual field into more manageable quasi-square/parallelogram-like sections. Add a head rest to keep the eyes steady, and the twins have trumped all traditional perspective drawings from the Renaissance onward.

    Anyway, I wanted so much more about the fact that we have TWO eyes, that are separated by several inches. How does light entering both eyes converge into a single percept? There was some reference to an optic nerve, but the eyes themselves seemed to be given the credit of actually “perceiving” things.

    Ryan and Trevor: http://oakesoakes.com/

  9. I knew a guy who had one eye and was a really good soccer player.

    This is very interesting… this spherical vision stuff. That issue has always been a pet peeve of mine in relation to Albertian one-point perspective. His system is an approximation on a flat surface, much as Special Relativity is a flat approximation of a curved spherical space. It’s much easier to do it on a flat plane. 3D is a bitch. Also, in Albertian perspective, you cannot move your head. You must fix your gaze at the centric point. I’m intrigued by your references and will look into them when I have the time.

  10. I don’t think my post ever went up… it says “awaiting moderation”. perhaps because I put up links? Anyways here it is without the links…
    With a lot of these readings I noticed a connection with the eye as a sort of gateway to the soul. I know in film theory, characters that are “bad” are not filmed with a reflection of light on their eye. Or in The Blade Runner, androids have a little red glare that gets reflected in their eye. There seems to be some sort of timeless fascination with reflections in eyes as some sort of humanizing trait. Maybe they are reflecting God’s light like in the Ibn Tufayl reading. I though there was a definite connection betweem threefold vision and Hayy’s vision of mirror’s reflecting the divine.
    Also, the reading on Alberti made me think of a couple of paintings. One is Las Meninas by Diego Velasquez. In this painting, Velasquez puts the viewer in a perspectivally impossible position. It is difficult to trace the vanishing point, but it does not lead where one originally suspects. Also, The Ambassadors by Hans Holbein plays with the mathematic perspective. He paints an unidentifiable object across the floor of the painting. If you view the painting from a side angle, the object reveals itself as a properly proportioned human skull.

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