PLEASE NOTE: I lied. Sorry. I was sure I could complete Alva Noe’s discussion of the Grand Illusion in one final blog post on the subject, but I know now that this isn’t possible without making this post improperly long, and I’m bordering on that right now. So, there will be at least one, or perhaps even two blog posts left on this topic. Hopefully, the material will keep you intrigued enough to read on.
I began writing this with the intention that the subject would be finished. Foolish me.
The following discussion is based on information that can be found fully described in Alva Noe’s book, Out of Our Heads: Why You Are Not Your Brain and Other Lessons from the Biology of Consciousness and Alva Noe’s article from 2002, Is the Visual World a Grand Illusion? I urge you to read both of these, but no worries if you choose not to, as I’ve read them for you and recount what I have learned below.
This post completes the topic I last wrote about in “Alva Noe’s Philosophical Concepts 6: Perception, The Grand Illusion Isn’t Real. Oh surprise!”. It’s important to put this topic to rest by finishing Alva Noe’s explanation of how the Grand Illusion concept is not just wrong, it’s “bad science.” While I don’t plan on writing much more about The Grand Illusion, I will be continuing my reading of Alva Noe as he explores and explains more about how perception isn’t something that happens all in our head. Of course, I will continue to share what I learn with you.
As it has been a while since my last Alva Noe post, I’m providing a very brief recap of the Grand Illusion concept that I’ve discussed so far. If you feel you remember what you’ve read before you can skip over the recap and jump into the deep end of the philosophical pool.
Grand Illusion Recap:
The “Grand Illusion,” in a nutshell, is a rather descriptive term used by Alva Noe and others, to explain the current accepted scientific explanation as to how our vision works i.e., that our brains essentially reproduce what our eyes see, meaning that we never really “see” what is out there directly. We’re always at least one-step away from reality. This is also known as “representational perception,” or even “reconstructionist perception,” which purports that vision is really produced by the process of our brains reconstructing the world “out there” and presenting it to our brains “in here”, based on information encoded on our retinas.
This theory, or rather this assumption, has been at the root of academic visual perception science for many years and is still the standard dogma, but is it correct? My previous Grand Illusion posts reviewed what Alva Noe has to say on this subject, which is essentially “This is wrong!” According to Noe, it’s not just wrong, it’s “bad science.” Needless to say, even though he is “just a philosopher,” he has caused a bit of a firestorm within scientific circles, since his criticism includes a detailed refutation of the much-acclaimed scientific conclusions of scientist Francis Crick (of DNA fame), for which Crick and his partner received the Nobel prize. Well, as Carl Sagan was oft quoted, “Extraordinary claims require extraordinary evidence.” Here Alva Noe comes into his element, because he deals with this erroneous assumption blow-by-blow, step-by-step, in a way that is not only highly understandable, but also logical, and in my opinion, a way that utilizes common sense.
So now, with your memory hopefully a bit refreshed, I will attempt to describe Alva Noe’s concluding thoughts on the Grand Illusion and put this beast to rest. I’m looking forward to moving on and reviewing what Alva Noe has to say further about how perception is not inside our heads, but is instead an activity we perform involving ourselves and the world around us.
Putting the Beast to Rest:
Alva Noe reminds us that when it comes to the scientific view of vision, certain ideas about it have been with us for centuries. For example, he tells us, “There is a discrepancy between what we see and what we really get from the world around us in the form of reliable, informative sensory stimulation. The brain’s job, it is proposed, is to make up for this discrepancy. The brain’s job is to compensate for the impoverished visual stimulus.”[i] This is an important reminder, as it denotes how scientists use the fact that there are discrepancies between – on the one hand, “…the character of our seeing,” and – on the other hand, “…the character of the information contained in the retinal image.” Based on this, scientists then conclude, or infer, that “…it is the brain’s task to make up for the lack.”[ii]
Noe then reviews several aspects of this theory that science typically relies on to support this position of how vision works:
- The Inverted Retinal Image and the Cyclopean Character of Vision.
- The Resolving Power of the Eye Is Uneven.
- The Retinal Image Is Unstable.
- The blind spot.
- Obstructions.
- The third dimension.
- Color.
- Time.
Here then are the highlights of each of the above points:
Inverted Retinal Image and the Cyclopean Character of Vision
I am not going to recount the standard rendition of what the retinal image is all about since I think everyone reading this post has heard of this supposed phenomenon. If you are unfamiliar with it you can read about it here. This wasn’t a new discovery. In fact, the inverted image phenomena was first discussed by Johannes Kepler back in the 1700’s. At that time, he raised a question regarding this feature of vision that is still valid today: “How is it that we manage to see the world upright when our eye’s image of the world is upside-down?”[iii] Good question!
But this question has deeper wrinkles you see, because there isn’t just one retinal image that is upside-down, there are two upside-down images, one for each eye! And not only are there two upside-down images, the images are not identical, nor are they very clear. So, what we should be asking is why we don’t see the world as two blurry upside down images and instead see one single, right side up clear image? (This is what is referred to as “Cyclopean vision”. Get it? ?).
Clearly we see some visual discrepancies here (pun intended) between what our eyes detect and what we actually see around us! Knowing this it is understandable why scientists since Kepler figured that the brain must be involved in straightening this confusion out by somehow flipping the images and combining the images into a single upright, clear image that corresponds to what we actually experience when we look around. As Noe says, “This reasoning—from discrepancy to what the brain must accomplish—is the foundation of almost all work in vision science.”[iv]
[Something to noodle over: If the brain’s job is to flip the retinal images, stabilize them, clarify them, and then combine them into one single, clear right side up image, and present this to our brains, then who or what sees the image? Is there another entity in our brains that is looking at this internal image? This flawed logic was dealt with way back in the days of Descartes. In fact, they even had a name for it: “The Homunculus Argument.”]
The Resolving Power of the Eye is Uneven
You are probably aware of “resolution power” when it comes to cameras or PC monitors e.g., high-resolution, low-resolution, etc. Well, our eyes have resolution power, too. We can see this resolution at work whenever we focus our gaze at something. In fact, studies show that the only way you can see a fully-focused image is when you zero-in on it i.e., gaze at it. Hmm. Why is this? The reason has to do with features in our eyes called “rods” and “cones” and the fact that our eye rods and cones are not spread evenly in our eyes i.e., “…there are many more rods and cones at the center of the eye (in the fovea) than at the periphery.”[v] There are also fewer color receptors at the periphery of our eyes, which means that at the periphery of our vision we’re essentially color blind!
Noe provides a couple tests we can do at home to demonstrate these conditions:
- Pick up a book and turn to a page of text that you’ve never read before. Shut one eye and stare at a word in the center of the page. Focus! Try real hard not to move your eyes. What you will discover by doing this is that you are unable to see more than a few words located where you are looking. Noe states that this works with two eyes, also.
- Fix your gaze on a point in front of you. Have someone place a playing card about a foot away from the card – up, down, left or right. While focusing on the point ahead of you, you will not be able to tell if the card is red or black!
Of course, neither of these situations is how we experience our perceptual lives though, is it? Instead, when we look at the world around us everything (hopefully, lol) looks clear, in focus and colored. So nice, yet our retinal images don’t look anything like this. Hmm. Is our only conclusion then, that our brain must be fixing the retinal images and color our world for us (at the periphery), thus building the image into some kind of “…internal picture of its own making”?[vi]
The Retinal Image is Unstable
Here’s a word you don’t run into much in mainstream media: “saccade.” Pronounced “sic cod,” more or less, this word refers to the “…rapid movement of the eye between fixation points.”[vii] You hopefully are physically unaware of this, but our eyes do not stay still, even though it surely seems they do. Instead they actually jump around several times each second and rather sharply, too. So we are experiencing eye saccades and micro-saccades many times each second! Yet, when we track a moving object with our eyes, the object image remains still on our retina while the stationary background “…races across your eyes.”[viii] Again, none of this is actually what we experience when we perceive. Thus, are we left once more with the only explanation for this being that the stability we actually perceive “…is achieved at some later stage in the processing of the original retinal image.”?
The Blind Spot
In my 6th post on Alva Noe’s philosophical concepts, I reviewed a demonstration of this blind spot phenomena. This refers to the fact that each of our retinas are missing photoreceptors, leaving a blank, or blind spot, in any image we are seeing, yet we never experience this (unless forced to, per a demonstration like the one I refer to). That’s weird, right? Noe then asks us to, “Close one eye and look at any uniform expanse of color, at the wall, say.”[ix] Do you see any discontinuity due to these blind spots? No, it appears to us that we are looking at the entire wall, yet due to the rods and cones in our eyes, we can’t see the entire wall. So what causes us to sense the presence of a continuous world (beyond the ken of our retinas)? Yep, you guessed it, this must be due to our brain’s activity, filling in the blanks and holes.
Obstructions
A few years ago, I had a pain in my eye. Nothing major, but it got my attention. Afterwards my eye was full of “floaters.” Have you ever had these? Most people do and they are quite common, but when you get a bunch of them they are hard to ignore, although you do learn to ignore them and they go unnoticed unless you focus on them. Quite irritating. Yet, unless I focused on the floaters, I was able to see perfectly well and this is even though light traveling to my optic nerve has to traverse the floater minefield. But, Noe says this is not the strangest thing. That honor is reserved for the fact that the retina itself is backward! “That is, the sensitive receptor itself is behind the web of nerve fibers that ultimately join to form the optic nerve. Light must wend its way through this morass of axions and dendrites.”[x] Here again, we are compelled to say that none of this is experienced by us, unless you get some of those nasty floaters.
The Third Dimension
Noe asks us whether we’ve ever had the experience of noticing what we believe to be the sound of a lawnmower down the street only to discover that it was the sound of a mosquito by our ear instead? He says that our eye is “…vulnerable to this kind of mistake as well.”[xi] Not surprising, perhaps, due to the fact that when we see anything, we actually only see a two-dimensional retinal image. Thus, a “…small object nearby can project the same pattern of retinal stimulation as a large object at a distance.” Wait, what? That’s right actually, as surprising as it seems. So, how is it that we can “…discern size or distance from a two-dimensional projection”?[xii] I did not know this, but this is apparently mathematically impossible to do. Yet, each one of us sees spatial relations all over the place. Thus, “…if we do in fact see spatial relations – if we can see size and distance – we don’t do so directly. This type of information just isn’t there in what is given to us.
Color
I’ve already explained that our eyes have few photoreceptors (cones) at the periphery of our visual field. Yet, even with this limitation, we experience a world that is colored in its entirety. Note too, that the color of the world around us is unchanging “…even as lighting conditions change radically. Noe tells us to look at a book and note that the color of the book doesn’t appear to change much “…even though the physical character of the composition of the light reaching your eyes from the book’s surface changes radically when you come inside into artificial lighting after having been outdoors in the midday sun.”[xiii]
Time
Ah, time, my second philosophical love. What has time got to do with our perception? A lot, actually. Noe recounts a fact we are all, no doubt, familiar with – that when we look at the stars in the night sky, we are looking back in time. That’s because the light from those stars took billions of years to reach us. Those stars may not even exist anymore. The light from those stars took a lot of time to reach us because it has to travel from those stars across the universe, to Earth, and our eyes. It is the same for any object you are looking at right now, even the objects in the room you are in right now. Our vision only gets started when light from the objects around us reaches our eyes. This light then triggers an electrochecmical response that then propagates “…at relatively low speeds along the fibers of our nervous system.”[xiv] Only when the signals hit the brain do we see. As Noe explains, this means that we don’t see things when we think we do. We are always behind, time-wise. This makes vision itself “…a kind of time travel, an access not to how things are but to how they were moments before.”[xv]
And so it goes…
With the descriptions above, I think Noe has done a great job of demonstrating how each of these visual foibles exhibits something in common i.e., “a common structure.”[xvi] That is, they each “…illustrate the way in which the character of our experience seems to ‘go beyond’ what is given and thus directs us to precisely the place where there is work for the brain to do: it is the brain that supplies what the world leaves out.”[xvii]
Noe tells us that this has been the main practice of vision science since Kepler’s day – “… to explain the mechanisms whereby the brain enables us to see much more than is present in the retinal image.”[xviii] In a nutshell: “Somehow, on the basis of two, tiny, discrepant, distorted, jumpy, upside-down, gappy, unevenly resolved, only partially color-sensitive, time-delayed pictures in the eyes, we manage to enjoy a unified and stable scene of objects and properties spread out around us in full color and volume in three-dimensional space. The task of vision science, as it has been understood from the time of Kepler down to the present, is to understand how the brain accomplishes this seeming miracle.”[xix]
Having done a solid job of laying down the groundwork, Noe now gets to the meat of the matter that’s been looming in the background by stating that we will have noticed something missing in every problem visual trait made above. Hmm. I think Noe is being generous here and instead should have said, “By now you should have noticed…” Because sometimes the obvious is obscure, at least to me. Did you notice something missing? There is no trick here. Something really is missing and it is glaring in its absence. I’m talking about the world. That’s right, the world. In every case described above, the world “…just doesn’t get into the act.”[xx]
Historically and even today, experts believe that seeing happens inside our head, that is – “… somewhere between where the light strikes the eye and the back of the head.” The world, in this commonly accepted scenario, is simply “…serving as some kind of offstage background.”[xxi] Somewhere out there the world titillates our nervous system via our senses, thus kicking just the right events into gear that cause us to see in here.
Beneath this currently popular theory of how we see is the belief that the world we perceive around us in all its colorful detail and rich textures is the end product of the brain’s visual activity. Scientists, Noe tells us, put a lot of emphasis on this. As mentioned previously, vision science is all about trying to explain “…how we can enjoy uniformly detailed, high-resolution, brilliantly colored images of the world when really we see so very little.”
There are, however, two groups of people who have understood for a long time that “…in many ways our visual experience is not as rich as it seems…” Here Noe is talking about magicians and movie set designers! This makes a lot of sense. He reminds us that the first rule of any magic act is, “…the hand is quicker than the eye.”[xxii] That’s because these folks know that, “to a surprising extent,” we only see what we expect to see. This makes us very suggestible! “If the magician gives us reason to think that he has taken the coin from one hand and placed it in the other, well, that’s just what we are going to see. Seeing is believing because, in effect, believing is seeing!”[xxiii] Remember the discussion in my last Noe post about change blindness? Science has shown us that we really do fail to see or notice much of what goes on around us.
I’m going to condense some of what Alva Noe talks about next and just recount that he tells us this idea he’s been talking about here has been standard dogma for visual scientists for a very long time. Noe calls this the “old skepticism.” Its primary tenet is that the brain builds a picture of the world and that’s what we see. Now, he tells us, there is a “new skepticism” afoot. I’ve mentioned it, actually, in an earlier Noe post. This new skepticism says that the fact that we think the world is built up by the brain just “…shows that we are even more profoundly deluded about the nature of our own experience.”[xxiv] We are, according to this new theory, “…deluded about the nature of our own experience.”[xxv]
This new skepticism says that we just think we see things clearly when in fact, we don’t! LOL. Where the old theory pushed the position that we actually see much more than is given to us, this new theory says that we don’t see more than is given to us, we just think we do.
It sounds kind of like bullshit to me, but some big names in the field of philosophy that I respect have pushed this theory along (Daniel Dennett, Susan Blackmore). It may still be bullshit, but I respect them enough to at least take the time to understand why they feel it may be correct.
Noe then sets about taking this theory apart. He says that this theory is wrong from the get-go. According to Noe, there is really nothing in our experience that would lead us to believe the world we are seeing is a built-up internal image in our heads. Nothing.
Rather, Noe tells us, “…it seems to us as if the world is here and we are here in it. When I look out the window, it doesn’t seem to me as if all the environmental detail is represented in my consciousness; rather, the detail seems to me to be there, in the garden, past the fence, across the street. If I want to describe what I see, I turn my attention not to my internal model but to the world. What I see is never the content of a mental snapshot; the world does not seem to be reproduced inside me. Rather—and this is the key—the world seems available to me. What guarantees its availability is, first of all, its actually being here, and second, my possessing the skills needed to gain access to it.”[xxvi]
He goes on and says that he can gather all the detail he wants of the world simply by turning his head, or “shifting my attention.”[xxvii] He admits that he does have the sense that the entire scene around him is present and it doesn’t seem to him that the scene is being brought into being by looking at it. How do we explain this? Noe shines a light on this by pointing out that although he can’t visually see the entire scene, he has access to it, “…—and moreover, in some basic, practical way, I know that I do.” Here, he uses one of his favorite examples, the tomato. He explains that when he looks at a tomato, how does he sense the tomato has a backside? He answers his own question, “…Just in the fact that I understand, in a practical, bodily way, that moving my eyes and head in relation to the tomato brings the tomato’s reverse side into view.”
I’m going to stop here, which is to me, personally, an appropriate place to pause because it was this type of example that Merleau-Ponty used that hooked me into a life-long love affair with phenomenology.
This saga will continue.
[i] Noe, Alva. Out of Our Heads: Why You Are Not Your Brain, and Other Lessons from the Biology of Consciousness (p. 132). Farrar, Straus and Giroux. Kindle Edition.
[ii] Ibid. pg. 132.
[iii] Ibid. pg.132.
[iv] Ibid. pg. 133.
[v] Ibid. pg. 133.
[vi] Ibid. pg. 134.
[vii] Wikipedia.
[viii] Noe, Alva. Out of Our Heads: Why You Are Not Your Brain, and Other Lessons from the Biology of Consciousness (p. 133). Farrar, Straus and Giroux. Kindle Edition.
[ix] Ibid. pg. 134.
[x] Ibid. pg. 134.
[xi] Ibid. pg. 134.
[xii] Ibid. pg. 134.
[xiii] Ibid. pg. 135.
[xiv] Ibid. pg. 136.
[xv] Ibid. pg. 136.
[xvi] Ibid. pg. 136.
[xvii] Ibid. pg. 137.
[xviii] Ibid. pg. 136.
[xix] Ibid. pg. 136.
[xx] Ibid. pg. 136.
[xxi] Ibid. pg. 136.
[xxii] Ibid. pg. 137.
[xxiii] Ibid. pg. 137.
[xxiv] Ibid. pg. 139.
[xxv] Ibid. pg. 139.
[xxvi] Ibid. pg. 140
[xxvii] Ibid. pg. 140.
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