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A theory of the brain

In 2022, I took a six-month leave of absence from work and did a lot of thinking about thinking, and in particular, how we think. I believed that, as with many things, if I better understood the process and mechanisms behind the thing (such as a car or a piano), I would be better able to use them. I start with a few basic premises that are important to establishing the principles that follow.

Why I did this

I wanted to be able to use my brain better. For example, I wanted be able to better make decisions (a perfectly common desire). There are lots of explanations and systems for explaining decision making, but I felt I needed to also know how my brain was making decisions in order to understand and hone what decisions I was making. Same with memory: I needed to know how my brain was forming memories in order to better form memories. Once again, there are many techniques humans have discovered to improve their memory, but I felt I needed to know why those techniques worked, not just that they worked. Why, for example, did the method of loci work, or a mnemonic device?

What I came up with was a theory of how the brain thinks. I call it a theory very intentionally. Like a scientific theory, it consists of a hypothesis that is verified by how it holds up to observation. A theory doesn’t have to be right, either, it just has to help explain something in a useful way. In this way, all of our theories are more heuristics. And as our theories advance, they oftentimes account for more observation, but that doesn’t make them necessarily more useful, or at least not more useful in everyday contexts.

When I refer to “our brains,” I am generally referring to the neocortex, rather than the “old brain” that is responsible for things like…

  1. Our neocortex can perform a few basic functions, from which all advanced functions are derived. Here, the analogy to a computer language is apt: there are a few basic manipulations, such as if/elseif/else statements, loops, and data organization that all more complicated functions are derived from. (And it may be worth noting that those basic functions are themselves operating from a basic binary logic within computer circuits composed of “gates” for AND/OR/NOT/NAND logic).
  2. These basic functions have developed from, and are in principle the same as functions in the old brain that was responsible for perceiving sensory input and, most importantly, navigating the world.
  3. These are the few basic functions our neocortex relies on: A. It can be aware of the current state of things based on its processing of sensory input (sensory processing). B. It can perceive change from one state to another state (short term memory). C. It can predict possible changes from the current state to a future state (prediction), it can predict possible changes to the current state.

From these three basic functions, all other thinking processes follow. Don’t believe me?

I bet you would say that there are a few other things the neocortex can do that are more complex than sensory processing, memory, and prediction. For example, you might point out that it can categorize and compare concrete concepts, it can formulate abstract concepts that have no basis in sensory input, it make rules for how the world works, and it can be aware of thinking itself.

I maintain that these, all all other “complex” thought processes are simply an extension of A, B, and C above. Exemplification may help:

“Categorize and compare concrete concepts.” For example, the brain can understand the concept of an apple and an orange, and enumerate how they are different in taste, texture, shape and color. I maintain that the brain’s conceptualization of an apple is simply its sensory input (A) being able to perceive the change in taste, texture, shape, and color between what we call and apple and an orange, relative to each other (B). It can remember a previously experienced apple when it is looking at a currently experienced orange. And it can predict possible changes (C): it can perceive that if the currently looked-at orange were instead red, and were instead smooth, and were instead sweet and tart, and apple-shaped, then it would be an apple.

In other words, the brain’s ability to compare apples and oranges is simply a function of remembering sensory input in relation to other sensory input. One way to think of what the brain is doing here (which is actually what it is doing) is on a map or a cartesian grid, where the axes are things like shape, texture, color, and taste. The apple is located in one place on the grid due its dimensions in shape, texture, color, and taste, and the orange somewhere else.

The brain’s ability to categorize apples and oranges as “fruit” as distinct from things it calls “vegetables” is just another cartesian plane with different dimensions, such as the dimension of edible component (seeds versus edible leaves or roots). Once again, the brain is simply categorizing and comparing one thing (or set of things) to another. It is creating a mental map of these things based on how they differ.

“Formulate abstract concepts.” If you would have said earlier that concepts such as “fruit” and “vegetable” are abstract concepts, the previous paragraph should help you see that abstract concepts are necessarily rooted on our brain’s categorization mechanism, and in its categorization of concrete concepts (sensory input).

If you would have said that “fruit” and “vegetable” are not abstract concepts but rather just category labels, then what about the concept of a mathematical triangle? Hopefully it is not controversial that even this abstract thing, that doesn’t exist in nature, is derived from A, B, and C: we perceive things like roundness or straightness through comparing things that are round (apple, orange, sun, moon) to things that are straight (redwood, branch, horizon, mountain). And here, it is simply “C” (predict possible changes from current state to future state: “What if I took the straightness of a redwood and made thinner, very very thin? I will call that future state a ‘line’. What if I took two lines and put their ends together, and then took a third line and attached it to the other two ends? I will call that future state a ‘triangle.’)

It’s really not any more complicated than that. If you’re having trouble accepting that, remember the comparison to a super complicated computer software – say, PhotoShop – and recall that it is simply composed of a collection of if/then/else statements (and ultimately ones and zeros).

Another way of thinking about it: an abstract idea is not really fundamentally different from a concrete idea: it is simply a derivative of various dimensions of the concrete things we interact with. Our brain’s ability to predict changes to sensory input can create the illusion of something more complex, but really, the ability to predict “what would this apple look like if it where the color of that black bug?” is the same basic mechanism as something seemingly abstract as “what if this apple was the color of something that I couldn’t see?” In this simple way, our brains can conceive of something we cannot experience through our senses, such as ultraviolet like. (And more recently in human history, thanks to technological advances, we can then prove our predictions about colors existing that we can’t see).

“Making rules for how the world works.” Hopefully it should be straightforward to agree that making a rule for how something works is ultimately “C”: predicting changes from one state to another state.

“Aware of thinking itself.” We can get to self awareness of thought through A, B, and C as follows: we can categorize physical objects in our brain and compare them. We can compare things that we are experiencing to things that we are not experiencing through our senses directly, and thereby conceptualize the idea of abstract things. We can compare the concept of abstract things to concrete things, and we can sense our process of comparing things and predicting things. Hence, we come up with a new abstract concept, thought, and we can identify when we are thinking of an apple compared to when we are thinking of an orange, and we compare the state of thought of the apple to the state of thought of the orange and call that process of moving from apple to orange in our brain a “thought.”

The reason the neocortex has these three tricks is because the old brain has them, too, and the basic biology of the neocortex follows that of the old brain. The old brain is responsible for navigation in the world, and it is really navigation, or movement, that is central to all neocortex thought. When we are young, our brain learns how our body moves through a series of perceptions of how sensory input changes when movement occurs (from moving our eyes to moving our neck to moving our feet). The old brain’s ability to take a step is based, biologically, on that part of the brain making a prediction about the intended movement, doing the movement, and then recalibrating its senses based on the new sensory input: “my foot is slightly further than I thought it would be; that means I put more muscle effort into that step than my brain predicted I would need; know I know that to go the distance I was originally intending, I should use less muscle effort.”).

All of this movement happens in the old brain, at the subconscious level. And much of what happens in the neocortex also happens at the subconscious level.

Our subsconscious thought consists of a few basic moves, all of which are involved in our brain creating new comparisons between sensory input or abstract ideas.

These moves include:

  1. Moving back to a recent thought/memory.
  2. Changing a property on an existing thought to move to a new thought that may or may not have occurred before.
  3. Establishing a “value” of the current thought. (From: is this food I see valuable to me right now? to “Is that hypothesis I came up earlier with about why I’m not sleeping well valuable, upon reflection?)
  4. Checking in on what our current “goal” or “task” is.

All three of these happen, again, at the subconscious level: we usually are not consciously directing a memory from the past or predicting a new thought based on applying a change to our current thought, or consciously thinking “should I eat this apple?” Of course, we can bring any of these things to the conscious level, but that doesn’t make them intrinsically conscious processes.

All Thought is Movement (literally)

The statement “all thought is movement” occurred to me in my idle contemplations about thought early during my six-month leave of absence. It was therefore so much more shocking to see the same bold and seemingly impossible abstract statement, verbatim, in Jeff Hawkins’ book A Thousand Brains: A New Theory of Intelligence.

One of the most succinct statements of the main principle in the book is on page 89:

Your brain has 150,000 cortical columns. Each column is a learning machine. Each column learns a predictive model of its inputs by observing how they cahnge over time. Columns don’t know what they are learning: they don’t know what their models represent. The entire enterprise and the resultant models are built on reference frames. The correct reference frame to understand how the brain works is reference frames.

The dizzingly self referential last sentence is one of my favorite because it is basically saying that the best metaphor for conceptualizing what is happening in the brain is what is literally happening in the brain.

  1. The concept of proprioception.

First the body. No. First the place. No. First both. Now either. Now the other. Sick of the either try the other. Sick of it back sick of the either. So on. Somehow on. Till sick of both. Throw up and go. Where neither. Till sick of there. Throw up and back. The body again. Where none. The place again. Where none. Try again. Fail again. Better again. Or better worse. Fail worse again. Still worse again. Till sick for good. Throw up for good. Go for good. Where neither for good. Good and all.

– From Samuel Beckett’s Worstward Ho

Kinaesthesia to Synaestheia

Manifestations of this in language

Think of all of the instances in language where we use the language of movement to describe thought processes:

There is an innate urge to think

Why do some people like movies with ambiguous endings and other people like movies that tie everything up in a bow?

No pain, no gain is actually a very literal statement about the brain’s pain receptors and movement

Stream of consciousness is actually a subset of identifiable mental movements

Why do big ideas feel hard?

It’s the brain realizing that the ideas are “too big” to hold in its short term memory, and there is insufficient reference frame mapping to create a full picture of the idea

Why do we doubt our ears more than our eyes?