What would Q-tips look like if we had three ears?

A Q-tip is a remarkable invention. It is a paper stalk with cotton batting on each end. They are sold by the millions, perhaps the hundreds of millions. The box lists all kinds of interesting uses for them, such as cleaning your computer keyboard. But we all know what they are really for: cleaning out the ears. For that they are excellent.

I find it particularly felicitous that there is a cotton tip at each end of the stalk, for a total of two, and we happen to have exactly two ears that need cleaning! What are the odds of that?

What if we had three ears? I don’t think Q-tips would sell very well then, because you would need a minimum of two Q-tips to do the job and would end up throwing away one of the Q-tips having used only one end of it. It just would not seem right and I don’t think people would use Q-tips so readily.

So someone would have to come up with a three-headed Q-tip, which is not inconceivable, but no matter what it looked like, it simply would not be as elegant as the simple double-ended Q-tip we enjoy today. It would cost a lot more to produce and would never work as well.

Having two ears is technically useful, especially when they are separated by the distance of the head, as in our case. That allows good echolocation, finding the source of a sound in space. You could do it with one ear, as a rotating or oscillating radar dish does, but that is technically complicated. You could have one fixed ear and scan it by moving your head from side to side, but you can’t move your head at the speed of sound, so precision would suffer. You would simply miss a lot of sounds.

Having a third ear would not give you any particular advantage over the two you already have, and would complicate the wiring quite a bit. The evolutionary cost would be high for very little gain.

So it turns out that two ears is just right: elegant, simple, economical, efficient. Just like a Q-tip, but for different reasons.

Bilateral symmetry in a body does not seem very complicated. The double helix itself is bilaterally symmetrical. So if you’re going to have one ear, you might as well have two. The incremental cost is negligible. But three is too many.

It just happens that a stick has two ends, so each end of a Q-tip can have a cotton swab. There is no a priori reason why that topological fact about sticks should fit so nicely with the symmetry of our developmental morphology.

There are a lot of forms in nature that are not stick-shaped, like loops and branches and ovals. Stick shapes are not terribly common. And of the stick shapes, many, like tails and antennae, do not have two free ends. And even of those that do have two free ends, the ends may not be symmetrical, as in a picked flower or a femur.

There is something non-obvious, even paradoxical, about purpose-built devices for the body. The body allows expression of human intentionality and yet we are perfectly capable of objectifying it to make devices like eyeglasses that hook over the ears. Convenient!

What good would t-shirts be if we didn’t have shoulders? Would scissors ever have existed if our thumbs weren’t just as they are? And isn’t it amazing that Q-tips have exactly two tips! Who thought of that?

We should appreciate Q-tips more for the elegant design they illustrate.

What is Introspection?

The fact that I can be aware of my own thoughts is preposterous. How is it possible? Is my cup aware that it is a cup? Is the coffee aware that it is hot and brown? Of course not.

Why should I be aware of what I am thinking? That is not reasonable. Nor could it have been predicted by any scientific observation. It is utterly perplexing.

There are many philosophical and quasi-scientific explanations of introspection. One is to deny that introspection is actually a fact. That eliminates a large anomaly from the purview of the scientific explanation of the world, but at the expense of self-contradiction. Introspection is required to understand what is being denied.

Another explanation is that one part of the brain becomes aware of another part of the brain, so really, introspection is just brain activity, completely physical. Beside the awkward fact that there is no scientific evidence for this hypothesis (nor could there be, since “awareness” is not a scientifically defined function of brains), this proposed solution does not answer the original question. I am a person, not a brain. It is I who have the introspective thoughts. If my brain also does a little introspecting on the side, so be it. Perhaps my liver introspects also. It wouldn’t matter to me.

What if we set aside self-contradictory and confused biological explanations of introspection, and consider only the mental experience? What is the experience of introspection?

We don’t introspect every minute of every day. On the contrary. Most of the time we are focused on the world, not on our own thoughts. But when we are focused on our own thoughts, what is going on? Who is focused on what? If I am the thoughts, who is looking at them? If I am the witness to the thoughts, who is in charge of the thoughts? I am pretty sure there is only one me.

This is one of the most profound mysteries confronting humanity.

Why the World Owes Me One Day

Some time ago I flew from San Francisco to Tokyo, crossing the international date line. It was Friday morning when I left and it was Saturday afternoon when I arrived, even though the flight was only about 12 hours. I lost a calendar day, as one does when crossing the dateline going west. Normally, you would re-gain that day on the return trip and everything would be fine.

But I kept going west. I went to Beijing, then Bangkok, New Delhi, and Mumbai. This all took a year or so. Continuing west for another year, I was in Istanbul, Sophia, Rome, and Frankfurt. I finally returned to the U.S. by flying from London to New York, and from there, back to Seattle on the west coast.

When I arrived home, I realized I never got that original day back that I lost going across the dateline. I had been robbed.

When I am on my deathbed and the grim reaper is nigh, I will have a legitimate protest: Wait! You can't take me now! The world owes me one more day!

Sensorimotor Dreams FAQ

These questions and answers concern "sensorimotor dreams" the most common type, which are also the foundation of social dreams.

What Causes Dreams?
During REM sleep, an area in the brainstem called the pons becomes active, causing the eyes to move about. Some researchers (e.g., Alan Hobson) believe that the pons activity is random and has no intrinsic meaning or purpose.

The pons is connected to the sensorimotor cortex at the top-center of the brain, and activates neural circuits there for basic sensorimotor behavior, such as reaching, walking, and moving the eyes.

The sensorimotor activation is not strong enough to cause actual bodily movement (other than in the eyes), or actual sensations, but it is strong enough to be experienced by the dreamer as reaching, walking, looking, and so on, and that is the dream: experience of random activity in the sensorimotor cortex.

Why do dreams seem meaningful?
Dreams seem meaningful because when you remember them you are awake, at least awake enough to say, "Wow, what a dream! I dreamed I was ..." When we are awake, we seek meaning and we find it. That's why there is a face on the moon -- we do not like random, meaningless patterns, and especially not random, meaningless experience.

As we recall the dream experience, we invest it with emotional and social significance. The process is like creative story telling. A list of the brain areas that were activated would be like a list of random paragraphs. But in recalling the dream events, we make them into a (more-or-less) meaningful story.

What is the meaning of this dream?
The source of the dream has no more meaning than a burp, because it originated from some brain circuits that became lightly activated as part of an automatic bodily process. But the dream report has all the personal meaning that any story you made up would have. As a creative product it reflects your interests, experiences and concerns, whether those are explicitly acknowledged by you or not.

Do most dreams have sexual or aggressive meaning?
There are basic brain circuits for sexual or aggressive acts, and these might have been activated during REM sleep, which you would have experienced as sexual or aggressive urges. In the same way, if you have an empty stomach or a full bladder, you might experience those in a dream as food scenes or as swimming in the ocean. You provide detail as you create the dream story at recall.

Do certain dream images have fixed symbolic meaning?
Certain images or thoughts have commonly recognized meaning because they are well-known cultural images. You don’t need an unconscious id or superego dreamwork for a sexual interpretation of a train plunging into a dark tunnel. It's a common image suitable to describe having experienced activation of a sexual arousal circuit. However there is no justification for most interpretations listed in books of dream symbols.

Does dreaming of spiders mean you fear being engulfed by your mother? There is no necessary connection. However, brain activation of tactile (touch) receptors on the skin could appear in a dream report in any number of expressive ways, including feeling enveloped, smothered, hugged, or covered in spiders.

Are dreams the royal road to the unconscious?
Analysis of dream reports can reveal hidden motives, attitudes and beliefs of the dreamer, but so can analysis and discussion of TAT stories (Thematic Apperception Test) and Rorschach (“inkblot”) responses, artistic products of all kinds, and even ordinary conversation. Dream reports may be fertile for this kind of exploration because they are typically recorded when the author is not fully awake, but they are not any more "royal" than any other creative product.

Why can I fly in my dreams but not in real life?
The dream story tries to accommodate the feelings of lightly activated brain circuits. If an activated sensorimotor pattern involves movement in space, then coordinated visual input would change accordingly. Sensorimotor patterns are interconnected in that way. But that particular complex of sensorimotor pathways might not involve any activation associated with walking or running, for example.

So how is the awake self, constrained by reality, supposed to interpret this vague dream experience? “I feel like I moved from Point A to Point B, and the perceptual scenery changed appropriately as I moved, but I didn’t walk or drive, or bicycle or swim. I don’t know how I did it. So I must have flown.” That is the most direct and “logical” explanation consistent with the “memory” (feeling) of the dream-activated sensorimotor circuit.

Why are dreams bizarre and irrational?
Dream reports are bizarre and irrational because they are waking fabrications constrained by the real world that attempt to articulate correlations between sensori and motor patterns felt in the brain. The dream story tries to flesh out a narrative from those minimal patterns and the result is like trying to construct a sonata from random groups of notes. The result is not likely to have much structural integrity, but might be creative and amusing.

Is it true that every dream is two dreams?
Yes. As psychoanalysts have said since Freud, every dream consists of the manifest dream report, and under that, the latent dream. The purpose of dream analysis is to use the manifest to understand the latent. But that process is no different in principle from how we analyze an utterance into its surface and deep structures or deconstruct an essay into its implicit meanings. Every human communication and social artifact has at least two levels: the manifest, realized product, and its latent, underlying intent. A dream report, as a creative product, is no exception.

Do we dream in color or black-and-white?
Neither. Dreams are attempts to explain certain bodily feelings, those of lightly activated brain circuits. Brain circuits have no color. It is completely dark inside the skull. However, the dream report might use either color or monochromatic imagery as appropriate in its construction.

Why can’t I remember my dreams?
What you have are feelings of lightly activated brain circuits at certain times of night. If you are not willing or able to conceptualize those into imaginative stories, then there are no dreams.

Is a dream a message from another dimension?
No, it is a complete fabrication of your own, formulated around dim experience of some lightly activated brain circuits.

Can I have a dream that does not belong to me?
Not unless you have circuits in your brain that don’t belong to you. However, you might construct a dream report using elements from public stories.

Why It Is Better Not To Know Italian

Puccini’s opera, La Boheme, includes some of the most beautiful songs ever written. I am especially fond of the arias and duet early in the play, when the starving writer, Rodolfo meets the waif, Mimi in his hovel. The romantic music and lyrics are enough to make anyone swoon. I don’t understand any Italian, but for some reason, that does not matter with music as fine as this.

However, I recently made the terrible mistake of looking up the English translation of the lyrics. What the two characters are actually saying (singing) to each other is depressingly banal. Rodolfo is saying something like, “Hey, baby, what’s your sign? Wanna blow this joint and grab some beers?”

That’s not a literal translation, but it conveys the sense of how utterly mundane the dialog is. Knowing that, pretty much ruins my imagination of high, spiritual romanticism. I have to will myself to forget the meaning of what they are saying. Too bad I looked it up. It is better not to know Italian if you love Italian opera.

What If There Had Been No Birds?

If there had been no flying animals, would the airplane have ever been invented? To even attempt flight, we had to believe it was possible. We had to see birds and dragonflies to get the concept.

Nobody today dreams of gliding through rock. Why not? What if there were animals in nature that could swim through a granite mountain and come out the other side? Assuredly, we would want to be able to do that too.

Would we have gotten the idea of flight from a maple helicopter or a dandelion parachute? We might have thought about gliding or floating downward, as seeds do, but never about hot air balloons or the Bernoulli effect. The Bernoulli effect might have been discovered anyway, but it would not have been applied to the problem of achieving human flight, because that would not even be a consideration. If there are no animals moving about in the sky, why would you even consider flying?

Anthropomorphism is the key. We have a certain physical empathy with the exertions of other animals and that is what prompted us to think, if they can do it, why can’t we?

What about flying squirrels or even leaping lemurs? Again, maybe we would have gotten the idea of gliding downward, but not flight. We have the birds to thank for Boeing, Airbus, and even NASA

Cracking Quantum Cryptography

There must be some error in my thinking here, but it seems to me that quantum cryptography has been over-hyped as being ultra-secure.

The idea of quantum cryptography depends on producing a pair of entangled photons. These are photons that have indeterminate polarization, either horizontal or vertical, say. But until they are inspected, it is not known what polarization they have, and indeed, according to quantum theory, they have no particular orientation until they are examined.

Being “entangled” means that when one member of the pair is examined, its orientation is at that moment determined to be randomly H or V, and automatically and instantaneously the same orientation is determined in the other member of the pair, no matter how separated the two are in space. Quantum entanglement is a well-documented phenomenon.

In Quantum cryptography, each member of a pair of entangled photons is sent to a different person. When Alice examines her photon and determines its orientation (H or V), she is assured that Bob’s photon has exactly the same orientation, because the two photons are entangled.

The change in status from indeterminate to determinate takes, literally, no time at all, which is how Bob’s photons manage to instantaneously match their entangled partners in Alice’s shop, across any amount of space.

Alice does the same on the next photon she receives. Each time this process is repeated, she records H or V orientation for the photon, lengthening her string of random, binary choices which becomes the encryption key.

The string of binary values (which could be represented as 1s and 0s) is random, and both Alice and Bob have the same string. Alice can encrypt her secret message with that key and confidently send it to Bob in ordinary email. It would be impossible in principle for anyone except Bob to decipher the message, since it is based on a random key.

How this technology differs from ordinary public key cryptography is that Alice and Bob do not have to share the key in advance. Having a shared key is less secure because such a “key” is typically a mathematical algorithm executed by a computer. Both parties know what that algorithm is. However, with a big enough computer and enough time, any such key can be cracked. With a quantum key however, there is no algorithm. The key is utterly random.

It is impossible to decipher the encrypted message without the quantum key, so you wouldn’t even try. Instead, you would attempt to intercept the key as it was being sent to Alice in the first place. Once you had Alice’s key, you could easily decipher her secret message to Bob.

If “Eve,” eavesdropped on the stream of encrypted photons headed for Alice, then Eve would have a copy of Alice’s key. But the photons would not look any different to Alice. They were always H or V at the moment she looked at them before, and they still are.

The standard answer to this attack is to note that Eve’s interception distorts the information encoded in the photons’ orientation in some way. I have no idea why that would be, especially for the “E91” protocol described here, where Alice and Bob each get one member of a very simple entangled pair.

In the articles I have read, it is just asserted that Eve’s interception would be detectable somehow. Probably the explanation involves some arcane physics or mathematics that I could not understand, so it is just as well that these articles do not say what errors Eve would introduce into a photon when she examines it. Let’s just assume that she does distort the key in some way however.

Nevertheless, Alice has no criterion for determining whether her quantum key has been tampered with or not. They are all just photons to her. If she were to compare her key with Bob’s, they would jointly determine that they did not match, since Bob’s photons had been previously disentangled by Eve, not by Alice.

But how are they going to compare the quantum keys? By sending them in an email? That wouldn’t be very secure. It defeats the whole purpose of the exercise. They cannot compare the keys prior to having secure keys with which to communicate. It’s a chicken and egg situation.

It’s true that Bob will not be able to decode Alice’s message, since their keys do not match, but Alice does not know that. So she sends her secret message by email, Eve eavesdrops on it, decodes it with her key that matches Alice’s.

Bob will realize that he cannot decode Alice’s message and will call Alice to let her know, and they will both realize there had been an interception. But by that time it is too late. Eve has the secret message.

Have You Ever Seen A Circle?

I was in the shower, looking down at the drain, and it appeared to be elliptical in shape even though I knew it was circular. So I moved my head directly over the drain to appreciate its true circular shape, but I couldn’t quite do it. For one thing, it was not possible to hold my head still enough that I could say for sure that I had seen a perfect circle. Secondly, there was a difference in point of view between each of my two eyes. Each eye saw the drain from a slightly different angle. Only one of them could be directly over the drain. Even repositioning my head with one eye closed, I couldn’t hold still, and anyway, I know that eyeballs always twitch about five times a second as a routine matter, so it was not going to be possible for me to truly apprehend the circular shape of the drain.

I realized that even the most sensitive scientific instrument, mounted exactly above the drain and kept absolutely still, could not measure circularity with zero error. There are probably instruments that can measure to 100 decimal points of accuracy, or better, but not an infinite number of decimal points of accuracy. Anyway, at some point, the measuring instrument would be so sensitive that no human being could calibrate it without error nor read its output without error. Besides, I doubt that the drain is genuinely circular in the first place. At some level of inspection, it surely would be “out of round”. So it became obvious that it was not possible, in principle, for me to ever apprehend the circular shape of my shower drain.

(Does this diagram show a circle tilted back, or an ellipse?
Joseph Brooks, socrates.berkeley.edu/ ~plab/earlygroup/shape.htm)

As the hot water began to turn cool, I concluded that there aren’t any true circular shapes in the world, and even if there were, as a practical matter, we wouldn’t be able to perceive them as such. Circularity could only be an abstraction; a generalization from many perceptual experiences of viewing approximately circular shapes, in comparison to other abstract shapes, such as ellipses. The mathematical formula for a circle is a further abstraction. In short, there are no circles, and nobody has ever seen a circle.
Except maybe Plato.

Plato appreciated the shower drain problem. He realized that objects of the mind, like the idea and image of a circle, are stable and perfect (and “eternal” he said). Objects of the world that we actually perceive are only approximations to the perfection of the objects of the mind, and on top of that, he knew that the body itself is forever changing, and inherently unreliable, so the appearances of things are always in flux.

By contrast, the perfect mental forms do not change. Plato called these the “essences” of things. The essence of something is what it truly is, its core nature, despite appearances. So my shower drain is truly circular in shape, despite appearances to the contrary.

But why assume something to which evidence speaks the contrary? The evidence is that the drain is not, in fact, circular. But Plato reasoned that if essences are perfect and eternal, and every object has an essence as its core, then every object must be perfect and eternal in its innermost nature. If our actual experience of the world contradicts that, well, so much the worse for experience. The experience is wrong.

But if experience is wrong, and always has been, how did Plato come to his theories about objects and their eternal essences? His whole life experience, like everyone else’s was erroneous. Plato’s answer is that he was just born with the knowledge of perfect essences, and so was everyone else. So there!

That’s a large pill to swallow. It is tantamount to the favorite argument of parents, “Because I said so!”

It is not necessary to assume that the perfect essence of an object resides in the object. Why can’t we say that essences reside in the mind, as inductive abstractions and deductive proofs? If that were allowed, then we would not be troubled by the fact that perception and measurement are inherently unreliable and that all objects are changeable. We could simply mentally accommodate for the error variance to infer the correct reality.

But Plato seemed blind to subjectivity, especially his own. Everything in his theory was “out there,” separate from the human mind, because he did not explicitly take the mind into consideration in his theory of reality. The best he could do was to say that the perfect and eternal essences lived in a special world, the spaceless and timeless World of Forms. The Forms were “out there” somewhere, although they would have to be in heaven to be in a spaceless and timeless domain.

So circles are in heaven. When you imagine you have seen a circle, you have actually glimpsed heaven. The same is true for a square, a triangle, or a dodecahedron.

In fact, we would have to say, keeping with Plato, that heaven is all you ever see. Everything has a shape, and a size, and so forth, because perceived things must have form. But when you apprehend and conceptualize a thing’s form, you are actually dealing with its Form, or essence, and Forms exist only in heaven. Therefore we have never, and cannot ever, perceive any part of the actual world, only the world of Forms.

(What shape is the rim of this cup?)

Plato’s is a profoundly antiscientific theory. Science is the observation and measurement of the actual world, not description of some theoretical heavenly world beyond space and time. So you would think scientists would be keen to avoid missteps leading to Platonist thinking. Yet they actually make the same mistake Plato made, assuming that everything is “out there,” nothing is “in here.”

In other words, scientists today are just as blind to their own subjectivity as Plato was to his. Scientific hyperobjectivity leads to the same reification errors that characterize Plato’s implausible theory of heavenly Forms.


Most scientists insist, for example, that patterns exist in nature that are not constructions of the human mind. I once pinned down a scientist who argued this way and asked him directly, “Do you really believe there is a face on the moon?” To my amazement, he answered yes. He said “If you set up an appropriate camera it will objectively record the pattern of a face on the moon without any human intervention.” (It did not occur to him that someone would have to look at the camera’s picture to prove the presence of a face).

Likewise, most scientists insist that there is objective “information” in the world and even “knowledge” independent of any knower. Many believe that numbers exist independently of the human mind, and so do space, time, energy, mass, and force. Theoretical physicists are convinced they are close to having a “theory of everything,” by which they mean everything in the objective world, which is the only world, in their thinking. Such hubris would be risible were it not pervasive.

Unfortunately, even the field of psychology, which supposedly specializes in the study of the human mind, has drunk the scientific Kool Aid. The American Psychological Association, and most of its members, insist that psychology is an objective science. Scientific psychologists have become blind to subjectivity, projecting and reifying their own minds onto the brain and the genome, the modern-day repositories of Platonic Forms.

What is the alternative? Abandonment of science and return to the prescientific darkness of ignorance and superstition? Hardly. All we need are a few tweaks to the philosophy of science to allow that subjectivity exists in the world as a natural fact and can be studied without shame.

Is Monotheism Obsolete?

If we are created in God’s image, and we believe that God is a self-sufficient individual, then so are we. That is how the myth of radical human individualism arose. Monotheism prompts us to see ourselves not merely as “the chosen people” (party to the covenant), but as individuals, self-contained, self-motivated, self-determining monads, just like God, in whose image we are created.

This myth of the individual has flourished and persisted to this day. It dominates Western philosophy, science, and psychology, especially cognitive psychology, which tries to explain the human psyche in terms of each person’s individual brain. But that’s not who we are.

The glorification of the individual psyche has been a mistake derived from monotheism. Put away the myth and look at the facts. The defining feature of the human psyche is that it is social. We are intensely social animals. We live with, for, and through each other. We cannot live without each other.

Language is a social invention, and to the extent that thought depends on language and linguistically based logic and conceptualization, thought is social. Even our most private and personal introspections and prayers, are social because we have internalized the image of the community and the thought processes given to us by the community.

It is not possible for a human being to live outside of human society. Sure, we can point to the lone monk on a mountaintop or the isolated recluse living in a forest. And what about Robinson Crusoe? But these are not true loners.

Through the decades-long process of socialization, one internalizes the language, values, assumptions, and concepts of one’s culture. The hermit on a mountaintop still has his language, memories, internal dialogs, and maybe books. He is still intensely social. The Unabomber was a recluse who shunned all society and lived alone in the forest. Except that he sent bombs to people, which is a social act. And when captured, his greatest wish was to publish a “manifesto” of his belief system. He was a nut, but an intensely social nut.

Robinson Crusoe? It’s a good thing his man Friday showed up or Crusoe would have eventually lost his mind. The internalized social community gradually fades away if it is not reinforced with new social interaction. After a time, Crusoe wouldn’t have had a thought in his head. He would have been reduced to a foraging animal, a human in outer form only. Perhaps De Foe knew that.

Children who are abandoned at an early age do not experience the years of socialization that create an internal representation of their social community. When such feral children are recovered by society, they are human in name and form only. They typically have no language, show no human emotion or understanding, and of course, know nothing of the ways of human society.

We are, above all other traits, social beings, intersubjectively linked to each other’s minds from our birth into a community. If we are created in God’s image, it follows that God must be similarly social in nature. Which implies a community of gods, not just one. Given the evidence, polytheism looks like a more reasonable idea than monotheism.

What are the implications of this conclusion? They remain to be worked out. I don’t think we should automatically assume a Greek or Hindu pantheon. We should develop our understanding of polytheism based on our peculiarly modern, Western ways of thinking.

But at least we can say that the doctrine of the cognitive monad can be set aside in favor of a more realistic psychology of intersubjectivity. And on the moral front, we can dispense with the absolutist thinking that derives from monotheism and which causes so much human grief. The implications for structured religion and Western society, are, of course, profound.

Perspective on a Difficult Idea

Linear perspective is an extremely compelling visual illusion. And it is an illusion. You know the train tracks do not really converge. If they did, the train would derail.

Why do parallel lines look like they converge in the distance? I think it is a learned response to living in a world of pictures. That interpretation is so overlearned, it occurs without explicit awareness. But it should be possible to unpack that illusion.

Linear perspective was invented in the early 1400’s by an Italian architect (Brunelleschi) and simultaneously by others trying to draw and paint, as a way to represent three dimensional space on a two-dimensional sheet. It is a good invention and it works pretty well. We do see "depth" in a flat picture, even though that is not literally possible because there is no depth in a flat picture.

In the 600 years since then, the technique has become so universal that pictures drawn without it don’t look right.











The artist, Albrecht Durer, in a famous 1525 lithograph, is shown using strings to represent the rays of light coming from the corners of his object. His canvas swings out of the way while he sights down the strings to the object. Then he puts the canvas back in place and makes marks where the strings would hit it. Connect the dots, and you have a mathematically correct map of what the actual object looks like from that point of view.

But what is it a drawing of? The sides of a walkway do not really converge in the distance. If they did, you couldn’t walk it to the end. So a perspective drawing is surely not an accurate representation of reality. Strings or no strings, the perspective drawing is a fantasy, like a unicorn. It is something that does not exist in the world.



Why then does the unrealistic perspective drawing look so convincingly real, at least with respect to depth? Is it because when we look at the world we actually see it wrong? When you look down a long walkway, not a picture of one, are you seeing the world wrongly? We know from practical experience in the world that parallel lines do not converge in the distance, so why do we see convergence? We have to make a mental correction: “The sides look like they converge, but really they don’t.”


I have spent a lot of time looking at scenes (not pictures, but situations) where there seemed to be converging perspective lines. Much to my wife’s consternation, I will often stop to stare down a long hotel hallway like the one shown here, and ask myself, “Do those walls really look like they converge, or am I only imagining it?” I will walk up and down such hallways, trying to understand what I am seeing, and hoping I won’t get reported to hotel security.

And my conclusion is this: I do NOT see the walls converging. I can talk myself into it, but if I turn off my metacognition, what I see is a continuously unfolding horizon and continuous visual information moving around my head. At no time do I worry that the walls are closing in on me.

If I stand motionless and look down the hall as if I were a camera taking a picture, then I CAN see convergence. But that’s because I am pretending to be a camera. I am using metacognition, the ability we all have to introspect on our own mental experience. Metacognition is what allows you to answer the question, "What are you thinking about?" To answer, you must think about your thinking process. For a visual scene, the question, "What do you see?" encourages metacognition. You must think about your visual experience. Instead of just having a visual experience, you are now one step removed from it. You have stepped back from your natural experience and instead you are now using metacognition to examine your own mental imagery.

We learn visual metacognition when we learn to understand pictures. For the last six centuries virtually all pictures used the linear perspective technique of representation, which is derived from metacognition, not simple visual perception.

It is extremely difficult to set aside the ways of seeing that you have unconsciously assumed all your life and which your culture claims is the “correct” way of seeing. When you look at a photograph, you automatically apply metacognition – actually you must. To understand a picture, you must abandon your natural, egocentric point of view and take up the special imaginary point of view implied by the picture so you can imagine you are looking at the scene depicted. It is a sophisticated shift in personal frame of reference, but we do it with ease.

It looks like the perspective lines are “in” the photograph because that’s how we have been taught to interpret such artifacts. A photograph is a 2-dimensional representation of a three-dimensional scene, so we apply Brunelleschi’s rules to it. Whipping out a Sharpie and drawing the perspective lines on the photograph only proves my point that we are using an artist’s metacognitive way of seeing the photo. But we don't normally do that when we are using ordinary cognition, as opposed to metacognition, in the real world.

When I look down the grocery aisle as if I were a camera, I am strongly tempted to see converging lines. Look at them there in the picture! I can do that, but why would I?

Never, when I have been shopping for a box of pasta, have I experienced converging parallel lines. Never. I just go to the pasta section and get what I want, and proceed to the next aisle. Not a single time have I worried if my shopping cart would fit out the narrow opening in the far end of the aisle. Linear perspective just does not come up when you need a box of pasta.

However, if I stand at the head of the aisle and imagine I am a camera, or an artist, and mentally "step back" from my experience, then pop! There are the convergence lines. But they are purely an intellectual, metacognitive, culturally contrived way of seeing, an overlay on my natural experience. I have been taught to see convergence lines and so I do. But when I do, I am not looking at the world any more, but instead, looking at my own mental imagery of the world.

Now that I have learned how to unlearn that cultural habit, I no longer see perspective lines unless I want to. That demonstrates to me that apprehension of linear perspective is not a native property of the biological visual system.

Discussions of the perspective illusion always present pictures to illustrate the points being made. I have done that here, too. I admit that the convergence lines are there in the pictures. Of course they are. But that’s because they are pictures! Metacognition is required to understand pictures, just as it is to read a map, a floor plan, or a blueprint. Understanding pictures is a culturally acquired skill. There is perspectival convergence in the pictures because that’s how we have learned to interpret pictures.

But if you observe the real world, not pictures, you can, with practice, get back into your natural attitude (non-metacognitive) way of perceiving, and there will be no linear convergence. Try it. Walk some hotel hallways and some grocery aisles and some railroad tracks. What do you really see? You will find that the sides do not close in on you. You do not really see linear convergence unless you imagine you are "looking at a scene" instead of being in the world. We CAN take an attitude of detachment toward our perceptual experience, but that is a learned, introspective skill.

It seems to me it would not be too hard to test this hypothesis experimentally, with infants and non-human animals. You could test them for discrimination of natural scenes with and without perspective elements (what most people would call perspective elements, like railroad tracks and hallways). My hypothesis is that there would be no discrimination between scenes conventionally interpreted as containing convergence, and those without. It would be hard to do this without pictures, but not impossible. I notice recently that some hotels go to great lengths to break up the perspective effect in their hallways by using alcoves, varied lighting and wall colors, and non-linear carpet patterns. It should be possible to find comparable but contrasting hallways.

Then you could train the animals or infants to discriminate comparable perspective and non-perspective drawings, then test them on the natural scenes again. If the training were effective, the post-test should show discrimination of scenes with convergent and non-convergent elements. However, It might be difficult to accomplish the pictorial training, as the skill takes a long time to acquire.

Who Cares?
Why does it matter whether we really see linear perspective in the world or just apply that cultural interpretation to what we see? I think it matters for two reasons.

1. It matters if we are seeing the world wrongly. We know the train tracks do not converge in reality but we see that they do. That’s wrong, a perceptual error. Well, if we see the world wrongly in that case, what else are we seeing wrong? What if it's all wrong? Is the world anything like what we think it is?

This is a fundamental question in the philosophy of perception. So-called “realists” believe that we see what is really out there. Sure we make errors, but over time, we generally understand what the world is really like.

On the other hand, “representationalists” say that our brain forms a neurological representation of the world and that is all we have to go on. We do not know anything for sure about the world in-itself. We know only what our brain represents for us, and that includes convergence lines of perspective.

I am a realist, and I have argued endlessly with representationalists about this. Representationalists tend to be interested in robotics and machines that can “represent” the world in computer memory. Representationalists use the illusion of linear perspective to argue, “It looks like the train tracks converge, but they don’t really. Therefore realism in perception is simply not true.”

My argument now is, “I deny that it looks like the train tracks converge. That is a learned attitude, an introspection, not natural perception.”



2. The second reason the perspective illusion matters is because it highlights a fundamental error people make about visual perception. The eye is not like a camera and does not work like a camera. Yes, the eye has a lens and a pupil (shutter opening) and the retina is analogous to a film. But the analogy is flawed and deeply misleading because an eye is a component of an active sensory system in an exploratory animal. A camera is an inert machine.

We do not look at our retinas, ever. The retinal image is nothing like the image on a film, and nobody ever sees it. A camera is passive, but vision is active, exploratory, selective, and cognitive. Recent developments in sensory substitution amply demonstrate how "mental" perception is (e.g., blind people learn to “see” from video signals translated into vibrations, sounds, pin pricks on their backs, or electrical signals to the brain).

Once you shake free of the erroneous camera analogy, you are free to see the world in your natural attitude, not through an arbitrary cultural lens.

Are the seats smaller in the back of this train?

Outlaw the Magnifying Glass!

How does a magnifying glass magnify? What is its secret? I looked into this recently and was amazed to discover that it works by playing on the human delusion that the world is just as it appears. A magnifying glass leads to a dangerous mind-game!

When you want to look at something very small, you have to move your eye closer to it, but there is a limit to that strategy. You can move a sheet of paper closer to your eyes but at some point it is too close for you to focus the lens of your eye on anything. For ordinary newsprint that distance is about 10 inches for me. Closer than that and the print is just a blur. The lens of the eye has a variable focal length, but it has limits.

Incoming light rays are bent by the lens at the top and the bottom, but pass straight through the middle. That’s how a lens works. The resulting image on the back of the eyeball is upside down, but we are so used to that, we don’t even notice it and we see the world as right-side-up.

To get a better look at a small object, we insert a magnifying lens between the eye and the object.






The magnifying glass is held close to the small object, so in the drawing above, the light rays from the object are diverging outward, so much so that an eyeball placed that close couldn’t bend them down to the scale of the retina (couldn't focus them).

The lens of the magnifying glass bends the rays of light just enough so they fit into the lens of the eye, which can take it from there and focus the object. You can move the magnifying glass back and forth until you find that good distance.

So now your eye can focus the object but why does that make the object seem bigger (magnified?). That’s where the mental delusion comes in. As far as the eye is concerned, if light rays come in at that angle, at that distance, they must be coming from a much larger object. The dashed lines show what the eye “assumes” about those light rays and where they came from.

The eyeball is not very smart and does not understand the optics of a magnifying glass. It only knows, from its whole life of experience, that when light rays come in at that angle, at that distance, the object is large. That is the message it sends back to the brain.

Consequently, when using the magnifying glass, we see the object as much larger than it really is, out of “eyeball habit.” THERE IS NO LARGE OBJECT out there. We see a magnified large object that does not exist! The actual object is the same size it always was. But by tricking the eye, we delude ourselves into seeing an imaginary larger object.

The larger, magnified object is utter fantasy, but we don’t interpret it that way. We implicitly assume that we are looking right at an actual object that just happens to be enlarged. As if objects in the world could really be enlarged on demand!

That’s not how the world works. Things are the size they are. They do not get larger because we wish them to. So why do we accept without worry that we have just magically enlarged an object? A magnifying glass promotes an incredible delusion!

Magnifying glasses should be regulated by the government. We cannot allow children to use magnifying glasses! A magnifying glass is far more dangerous in distorting the mind than any hallucinatory drug.

What is Laughter?

Laughter seems to involve a spasm of the diaphragm, but so does a hiccup, and laughter is not a hiccup. Both are involuntary, but that’s not much help.

Laughter has a stimulus, some visual or semantic event, even if only a memory, that triggers it. You don’t break out in laughter for “no reason.” Something makes you laugh.

Incongruity Hypothesis
Usually the triggering input is something unexpected, out of context, incongruous. Man slips on banana peel and falls. Ha-ha. That’s not supposed to happen. The context shift need only be very slight as with a pun, or a small reversal of semantic or attentional figure and ground, as in a riddle. A violation of expectations is funny. Sometimes.

At other times, violation of expectation is infuriating, as when a vending machine keeps your money and gives you no product. Not funny. Unless it happens to somebody else, perhaps. Violation of expectation can also provoke fear, even terror. So the incongruity hypothesis needs qualifications.

People laugh and giggle after smoking marijuana, possibly because the cognitive changes from smoking result in much relaxed expectations due to limited short term memory and short attention span. Under those conditions, it doesn’t take much to violate what few expectations are left.

Similarly perhaps, I am susceptible to fits of uncontrollable laughter when I am extremely tired. Again, there is a factor of diminution of cognitive faculties that accompanies extreme fatigue.

Tickling may produce laughter because of the incongruity of having your body stimulated in an unexpected way. The incongruity hypothesis is not an easy fit there, but it could be made to work.

Are clowns funny? They are for many children because they violate expectations of what is normal, both in the way they look and the way they act. But many children are afraid of clowns, so the violation of expectation hypothesis can only take us so far. Perhaps it must be a mild violation of context, or at least, one perceived as harmless. So safety seems to be a factor correlated with the incongruity hypothesis.

We laugh when something is funny, but for the most part, what's funny is culturally defined as whatever makes you laugh. Circular though that argument is, it suggests for the incongruity hypothesis that expectancies are culturally defined.

One group’s sacred ritual is another group’s comic farce. It all depends on what you expect and don’t expect in the normal course of things.

There are numerous physiological correlates to laughter in the brain, but that doesn’t tell us much, since we don’t know if they are causes or effects, or some mixture of both.

Likewise, laughter results in numerous changes in the body, but that doesn’t help us understand what laughter is or what causes it. Laughter can lead to tears, but that doesn’t make it the same as crying.

Social Hypothesis
Another hypothesis is that laughter is a social phenomenon, possibly a form of communication. Why can’t you tickle yourself? Maybe because that is uncommunicative. It takes two to laugh.

Of course you can laugh when you are all alone, but according to the social hypothesis, it’s when you are remembering a social situation that makes you laugh.

Laughter is often contagious, additional evidence for its being a social, rather than strictly an individual phenomenon, and more reason to think that it serves specifically a communicative function. What is the communicative message? I don’t think it’s necessarily a conceptualized, linguistic proposition. It seems more like an implicit social understanding, like “We are together now.”

Temperament
Despite the social hypothesis, a third component of laughter seems to be individual mood and temperament. I've met plenty of people I thought were humorless, yet everyone believes they have "a good sense of humor." I’ve never heard anyone say they have no sense of humor. Yet the plain fact is that some people are just not easily amused, while others can find almost anything funny. Humorless people perhaps feel under threat to the self, and if they are never safe, violations of expectations are fearful rather than funny.

Embarrassed laughter supports that hypothesis. Embarrassment arises from a violation of expectation, and can also produce laughter, if the personal threat is not too great. Phony laughter can pretend that the threat to self was insignificant, even when it wasn't.

Conversely, we might expect that people who are self-assured would have a more finely tuned sense of humor, meaning, they would laugh more readily at a wider range of incongruities. This could be tested experimentally, and probably has been.

I don’t think laughter is an emotion. And I don’t think emotions produce laughter, although laughter can produce happiness. We might try to make a grumpy person laugh just in order to elevate their mood. But the laughter is not the mood.

Any temperamental factor would be confounded with socialization, so there’s no way to get a clear picture of it.

Darwin
Charles Darwin, in his fascinating book on the Expression of Emotions in Man and Animals (1898) Made the connection between laughter and aggression. We notice that laughter almost invariably involves showing teeth. Darwin surmised that it might be because laughter is similar to a self-defensive display of aggression.

I don't care for evolutionary "just-so" stories like that, but the conjecture is at least consistent with some of the other ideas I have put forward. If the perceived incongruity is felt to be threatening to the animal or person's self, then one natural response would be self-defense, and one way to demonstrate that is by showing teeth. It doesn't ring completely true to me, being based only on superficial observation of facial expression and not phenomenological analysis, but it is not unreasonable.

Individual Differences
There is another idiosyncratic factor about what makes a person laugh, and it may be different from temperament. Perhaps it is socialization history. Often it is surprising what will make a person laugh.

For example, my wife, a well-educated, articulate, and thoughtful person, loves slapstick physical humor. When she sees somebody walk into a door and bang their head, in a comedic context, she might laugh until tears come to her eyes. Her laughter makes me laugh, but I look at her with bewilderment. Who is this person that thinks a bump on the head is so funny? It’s unfathomable.

For myself, I am partial to linguistic jokes. I love badly formed, ambiguous newspaper headlines, for example, clever captions to cartoons and sly puns. I also enjoy well-observed satire, which relies on good phenomenology. People bumping heads is just not funny for me.
I don’t think those kinds of differences are merely temperamental, but it is difficult to say what could account for them, other than, vaguely, “socialization.”

Animals
Do animals laugh? Many animals make noises, show emotional expression, and vocalize in situations that suggest to us that they are laughing. Chimpanzees especially seem to laugh and they have the cognitive capacity to understand when an expectation is violated. I have read that it is possible to tickle a rat and make it emit a special noise that can be heard with instruments. Is that laughter?

We can’t know if animals laugh because we lack sufficiently detailed intersubjectivity to understand their minds as well as we do with each other. I can be pretty sure when you are laughing because we are the same kind of animal and we know each other’s minds. Speculation about whether animals laugh is best put aside until we understand better what human laughter is.

What is Laugher?
One memorable account of the origin of laughter came from an eight year old boy. When I asked where laughter comes from, he said, "From God. Or maybe from my butt." The first answer says, “Laughter is a part of me that does not originate with me.” The second answer expresses the sudden, involuntary, and inexplicable quality of laughter.