A Conversation with Kim Dae-Shik

Brain in the Head: the Ultimate Source of Folding in Space and Mental Extension

January 10, 2015


Kim Dae-Shik in Conversation with Moon Kyungwon & Jeon Joonho

Moon Kyungwong & Jeon Joonho: Our new film The Ways of Folding Space & Flying stems from the concept of chukjibeop and bihaengsul, which is really about the indefatigable human nature to defy against perceived boundaries or “reality.” We see art as physical or conceptual manifestation of this defiance. This naturally leads to the question of how human brain perceives reality. Can you talk about this perceptual process? And also freely discuss how you interpret the concept of chukjibeop and bihaengsul in relations to your studies of neuroscience?

Kim Dae-Shik: The origin of the problem is somewhat bizarre, yet straightforward: the brain is in the head. Of course, the brain is in the head. Where else should it be? What this rather obvious statement denotes is this. The brain does not know what reality is. It cannot, period. Not unlike the prisoners in Plato’s cave, the brain is just a 1.5 kg piece of meat hidden inside a well protective prison, called “skull.” With 50 million neurons and several hundred kilometers of axons terminating in almost one trillion synapses for every cubic centimeter, and consuming only about 12 watts energy for the entire cortex, the brain is arguably one of the most complex and efficient information processing systems known to mankind. Yet, while the brain is undeniably the seat of sensory perception, motor coordination, memory, and creativity – in short, what makes us humans to humans - everything that we see, hear, feel, and smell have to be conveyed indirectly through our sensory organs. The brain knows about the world only through our senses. More precisely, events in the external world (assuming its – unprovable – existence) trigger a chain of chemico-neuro-electrical activities, which ultimately generate a spatio-temporal pattern of neural activity in assemblies of cortical neurons. The brain tries to make the best out of these chaotic waves of neuronal activity by extracting statistical correlations between them. What we “see” is the result of such statistical inferences. That is, the visible world as it appears right now in front of our eyes is the “output” of our brain’s guesswork. We never see the world AS IS, when it was imprinted into our sensory organs as untainted “input”.

Every perception is interpretation, and every interpretation of the brain elicits perceptual qualities. Some of the interpretations are accurate (i.e. there is a one-to-one relationship between sensory event and percept), but mostly they result in sensory and cognitive “illusions”. In fact, without such active interpretations, we would not be able to make sense of the world at all. For example, the only observable physical events in the retinae are statistical distributions of incoming photons. There are no colors, no shape, and no depth information. Depth, shape, and color are all perceptual qualities generated at later stages by the brain as part of interpretative processes.

Let’s posit for the moment that the world we perceive is indeed not the “objective” input, but rather a “subjective” computational output of the brain. Does that mean that different brains will compute different outputs? Obviously! Felines have rather poor color vision, ergo their perceived world will resemble grey scales images. This, we can imagine. But what about the perceptual qualities of chiropteras (e.g. bats)? They perceive the world using ultrasound waves. While they may not have conscious experiences as humans (but who knows?), bats certainly perceive their environment for hunting, mating, and navigation, even in dark. However, lacking similar ultrasound capabilities, it is impossible for us humans to imagine how it is to be a bat, and to perceive the world as bats do. How about then differences between humans? Since no two human brains will be perfectly identical, we can safely assume that no two human brains will compute perfectly identical perceptual outputs. Why then, do we feel that we all live in the same world, and talk about the same world?

Let me give you an example. If I hold a red apple in my hand, and ask you what color it is, you’d probably tell me it is “red”. Well, fair enough. But let’s think about it again. Do I really see the pure color “red” if I see an apple? The actual color of the apple will be a mixture of multiple colors; it will also have complex texture and shading. All these percepts however, cannot be expressed using language as we do not have words, which precisely express what my eyes see. Instead, we summarize the totality of our percepts into a singular word “red”. Similarly, while your brain will compute a sensation of the apple that is somewhat different from my own, you will also use the word “red” to denote the complex sensation you generated in your brain. I say “red”, and you say “red”, and we falsely conclude we are talking about the same world.

Simply put, the “resolution” of our language is much coarser than our perceptual resolution. What is true for visual world, is likewise true for everything else the brain computes. A piece of music (say, J.S. Bach’s Goldberg Variations) is nothing but vibrations in the air, unless it is perceived and then computed by the human brain into a beautiful piece of music.

Same so also for space and time. While the ultimate nature of space and time is governed by laws of physics (Relativity? Quantum mechanics? High dimensional Branes? Multiverse?), its subjective nature is determined by the brain. Returning to your question about chukjibeop and bihaengsul, you want to stretch your time? Nothing simpler than that! Just increase the sampling rate of your neurons, and you will start to perceive the world in “slow motion” (as children and flies do). You want to “fold” space? Sure, why not! Just change the trajectory of the hippocampal waves of neural activity that maps the spatial coordinates in the brain. You want to ignore the laws of gravity, and magically levitate yourself outside of your body? Well, you may be interested to remember that the overlap between body and self (or mind) is learned, not given. A newborn baby does not discriminate between its own body and the world. Only gradually, the baby learns that a subset of the visible world is in a causal relationship with what she/he wants. This subset becomes “me”, as it is the part of the universe that somehow follows the commands generated by the piece of meat inside the skull.

Moon & Jeon: So the self is a set of associations? That would truly enable anything yet disable everything at the same time, leading us to the big question of how to define the concept of “meaning.”

Kim: Yes, the self is not static. It extends and shrinks. The radius of the self is the radius within which I can will and cause. Connect a long stick to a newborn monkey’s hand, and gradually, the monkey’s brain will extend its “hand representation” towards the tip of the stick. Our self extends to the limits of what we can control. It does not have to be limited by the boundaries of our physical body. Meaning comes into the universe through our brains. Universe minus brain is chaos; but universe plus brain is cosmos.