Hidden In Plain Sight 9: The Physics Of Consciousness

by Andrew H. Thomas

I hope you get the message that it is very difficult to describe consciousness in anything but very vague terms. However, that is not to say the task of recognising consciousness is impossible.

This book, however, will take a slightly different approach. In this book, we will be tackling the problem from the viewpoint of physics, mathematics, computer science and artificial intelligence — and even some electronics.

Descartes declared that the mind was made of fundamentally different "stuff" to the rest of the body. The mind was non-physical, and was distinctly separable from the rest of the body. This philosophy is called dualism.[1] Descartes even suggested a region in the brain where the mind might be found: the pineal gland, which is a small gland in the centre of the brain.

This apparent paradox is called the mind-body problem. It is similar to the question of how ghosts in movies can walk through walls, but conveniently do not fall through the floor.

We would surely feel the same even if our consciousness was transported to completely different hardware. This principle — that consciousness is independent of the underlying hardware — is called substrate-independence.

The principle of substrate-independence is described by the neuroscientist David Eagleman in his book The Brain: "If that turns out to be true, then in theory you could run the brain on any substrate. As long as the computations chug along in the right way, then all your thoughts, emotions, and complexities should arise as a product of the complex communications within the new material. In theory, you might swap cells for circuitry, or oxygen for electricity: the medium doesn't matter, provided that all the pieces and parts are connecting and interacting in the right way. In this way, we may be able to 'run' a fully functioning simulation of you without a biological brain."

If every axon, synapse, and nerve cell in my brain were replaced with wires, transistors, and electronic circuitry performing exactly the same function, my mind would remain the same. It is not the nature of the stuff that the brain is made out of that

matters for mind, it is rather the organization of that stuff — the way the parts of the system are hooked-up, their causal interactions. A fancier way of stating this is 'Consciousness is substrate-independent'."

Taken to its logical conclusion, substrate-independence appears to suggest that there is nothing preventing a sufficiently-compl...

So our challenge appears to be to try to find where this peculiar "immaterial" mind substance can be found within the Standard Model.

Well, perhaps surprisingly, the Standard Model has the answer as to whether or not something immaterial can affect something material. The solution is that it is absolutely no problem: yes, something immaterial can definitely affect something material.

So here in one diagram we have an answer to one question which is often raised about the mind-body problem: "Could it ever be possible for something immaterial to affect something material?" The answer — according to the Standard Model — is yes it can, and this is how. The question raised earlier was how could there possibly be an interface between the material and the immaterial. Well, the previous vertex describes just such an interface.

There is a different substance, a different candidate to be considered the "stuff" from which our consciousness is made. This substance is completely tied to the physical world, it is therefore represented in the Standard Model, but it also appears to inhabit a realm above the physical world. What is more, it possesses the desired substrate-independence because it can traverse the world of both fermions and bosons — the material and the immaterial — giving an impression of how it might represent a potential solution to the mind-body problem.

In 1948, there were two major developments in the Bell Telephone Laboratories which might initially appear unconnected, but acting together they were to create the modern world. The first announcement was of the invention of a tiny electronic device, described in the press release that "it may have far-reaching significance in electronics and electrical communication". That was definitely an understatement. The tiny device rather unimpressively resembled an insect with a small body and spindly legs. It was called the transistor.

Shannon's paper introduced yet another new word: the bit.

Shannon said it himself. The bit was: "A unit for measuring information."

The word "bit" is a contraction of "binary digit".

When information is transmitted or stored, it is common to use an alphabet of symbols. The most widely-used alphabet is the Latin alphabet, with its modern day English, French, and Germanic variants. But the same principles apply to any alphabet of symbols.

We would obviously need the 26 letters of the English alphabet ("A", "B", "C", etc.) and the 26 lower-case equivalent letters ("a", "b", "c", etc.) requiring 52 characters in our alphabet. But there would also be other characters required for punctuation, such as the full stop (period), comma, and hyphen, and — of course — the "space" character between words. Other characters which might appear in a text document include the dollar sign, the ampersand, and bracket characters. So it appears our alphabet would require in the region of about a hundred characters, or maybe slightly more.

To cut a long story short, such an alphabet for representing text in computers has been constructed and it is called

the ASCII code (American Standard Code for Information Interchange). There are 128 characters in the ASCII alphabet. Those characters are given numeric codes from (0 to 127) in order to be t...

In order to be transmitted as a stream of information, each character is converted into a seven-bit code. Why seven bits? That is because in the binary numbering system it is possible to represent a number from 0 to 127 using seven bits.[2] Here are a few of the ASCII character...

Shannon stated that the amount of information, H, transmitted by a series of n characters is given by:

But where have we seen something similar to the previous formula before? If you have read my third book you will realise that this formula for the amount of information is very similar to the formula developed by Ludwig Boltzmann to describe the amount of entropy in a system (the Boltzmann entropy formula). Here is Boltzmann's famous formula, as carved on his gravestone:

Claude Shannon had revealed a correspondence between information and entropy.

So, by introducing the idea of the bit as a measure of information, Shannon had shown that information could now be treated, measured, and analysed as if it was a physical substance.

Information could now be "compressed" like a gas (for example, to reduce the size of a movie file on a hard disk), or "filtered" like a liquid (for example, to extract interesting search results).

In our thought experiment, the gremlin is going to be doing a lot of thinking. However, rather bizarrely, the gremlin is going to do no actual physical work.

We are then going to define "thinking" as the process which must have occurred in the gremlin's head in order to produce the observed effects.

In 1867, the great Scottish physicist James Clerk Maxwell wrote a letter entitled "On the Decrease of Entropy by Intelligent Beings". In the letter, Maxwell proposed a famous thought experiment called Maxwell's Demon.

The mystery becomes even deeper if we consider the trapdoor to be completely frictionless. In physics, "work" is defined as the distance an object is moved against a force. If the trapdoor is frictionless, then it will exert no force against the hand of the demon, and therefore the demon will have to perform no actual physical work in order to open and close the door.

This result was described the American physicist Carl Eckart: "Thinking generates entropy".

All of this represents the capturing of information, and the processing of that information. So we can define thinking as information processing, and we can consider the brain to be an information processing unit.

"The 'stuff' of mind is pure information. Information is neither matter nor energy, though it needs matter for its embodiment and energy for its communication."

Information appears to be a perfect fit for the material of our thoughts, the substance out of which our consciousness is made.

blindsight.

In his book, The New Science of Consciousness, Paul Nunez considers the situation in which a small child runs out in front of the car you are driving. Your unconscious mind would slam on the brakes of the car as a reflex action, and this can be performed in 150 milliseconds — which is much too fast for the conscious mind to reason about the situation (imagine the mental dialogue: "Should I start to brake?" — far too much time wasted). In fact, conscious awareness of the child does not emerge until a full half-a-second (500 milliseconds). Your conscious mind is not aware of any delay — it is as if your consciousness is always lagging half-a-second behind the reality of the situation.

It is the cortex that is the centre of our memory, awareness, thought, language, and consciousness.

neocortex,

allocortex

Because conscious processing appears to be confined to the cortex, we will only be considering the cortex in this book. In his book On Intelligence, Jeff Hawkins follows a similar strategy. In the following passage, Hawkins defends his preoccupation with the cortex, and is fairly dismissive of those who disagree:

"We are going to focus most of our attention on the cortex. Almost everything we think of as intelligence — perception, language, imagination, mathematics, art, music, and planning — occurs here. Your cortex is reading this book."

The neurons are so tightly-packed within the cortex that the thin cortex layer actually represents 40% of the total brain mass.

How can such a thin layer be responsible for all our high-level brain functions? Well, the cortex achieves this by expanding as far as possible in width and breadth, in other words, by increasing its surface area.

The cortex needs to maximise its surface area, so it is positioned on the outer surface of the brain (the outer surface of a sphere has the greatest surface area). Conveniently, that means the cortex can cover the unconscious part of the brain, which, in turn, acts to filter the signals coming in from the centrally-positioned spinal cord.

wrinkling

Y arrugándose

If you could remove the cortex and spread it flat, it would be about the size of a small tablecloth, revealing how the wrinkling acts to increase the processing capacity of the brain. Many animals have perfectly smooth brains as their cortex does not grow enough to push against their skulls.

As an example of the function of the lobes, it is believed that the frontal lobe is where most of our imaginary thinking and problem-solving takes place, as well as language processing.

How have neuroscientists discovered which part of the brain is responsible for which type of behaviour? Well, originally it was discovered that people with brain injuries in different parts of the brain displayed behaviour which was characteristic of the site of the injury.

The first example of this came from the work of the nineteenth century French physician Paul Broca. One of Broca's patients was nicknamed "Tan", because that was the only word he could say.