Can Physics Explain Consciousness? | Professor Steven Gimbel discusses quantum consciousness

Transcript

We've seen that the combination of a grand unified theory with a quantized account of gravitation is called a theory of everything by physicists. In this conversation, we want to see how seriously to take the word everything in this phrase. If researchers succeed in the ultimate goal of physics, a single coherent theory that unifies the working of all four known forces in the universe, what does this mean for our picture of reality? Would it mean that we not only completed physics but also completed our inventory of the furniture of existence? Would a theory that explains how all matter, energy, and interactions among in between them in terms of field values and symmetries give us an exhaustive account of all we should consider to be real? This view hinges on what we've discussed as the doctrine called reductionism. that is that everything studied in every science reduces ultimately to physics. This reductionist position is committed to two claims.

First, everything that exists is made up of nothing more than the elements of physics. There are no extraysical entities in the world. And two, the laws and vocabulary of each science are just shorthand for a more complicated set of laws that can be set out fully in the vocabulary of physics. We'll discuss the first of these at length here and touch on the second just a little because the second proposition will be investigated in more detail later in the course. Reductionists contend that everything in the universe is made up of atoms and energy.

The long-standing resistance to this claim points to the existence of life as a metaphysically different kind of thing. Okay, if we take a living being immediately before and then the instant after death, all the atoms that were there beforehand are thereafter. But the thing is fundamentally different, right? We differentiate linguistically between a person and a corpse. We think intuitively that the two are different, right? Another word we use for corpse in ordinary language is body. Right? When we say somebody has died, we say that his or her body is here, but that he or she, that is the person, is gone.

We equate being a person with not just having a body, but also something else. Traditionally, this something else is a soul. This two-part picture of reality that there are two separate sorts of things in reality, physical bodies and non-physical souls, is what philosophers call metaphysical dualism. The great name attached to dualism is Renee Deart, who's already come up in a number of our conversations. Recall Decart's evil demon thought experiment we talked about in the very first lecture, right? Decart said, "Consider the possibility that we are being fooled by an evil demon who's putting false ideas in our minds." Right? He's not saying it's true, but argues that it's conceivable, merely possible.

And if it were true, then any given thing I think, any proposition I believe could be false, right? Put into my brain by the demon. Hence, I could believe nothing about the material world, not even that it exists, since it all may be an illusion, the result of a complex hallucination created in my mind by the demon. Seems like I could believe nothing about reality. But he realizes there is one thing even the evil demon could not wrongly convince me of. That I exist.

The demon could not fool me into wrongly believing that I exist because I would have to exist in order to be fooled. The demon would have to create the thought of existence, but the thought requires a thinker. And thinking is doing, and doing requires a doer. If I'm thinking, I must exist. And to be fooled, I must first think.

So, I can't be wrong about my belief that I exist. But what am I? I'm not the person I think I am with the body I think I have in the world I think I inhabit. All those beliefs could be the result of the demon's handiwork. The only thing I have the right to believe with absolute certainty is that I am a thinking thing, a thing that thinks, a mind. And so Decart concludes the mind exists separate from the body.

Now he later goes on to try to prove with mathematical certainty that the body exists and that there are absolute laws of mechanics that the body has to obey. But these laws are the laws of matter, not those of the mind. Mind and body are completely different things, different kinds of substances. Reality is comprised of two separate realms. the material world governed by the immutable laws of physics and the world of mind that's governed by logic or psychological rules or ethical rules or no rules at all.

The human mind seems to be a different sort of thing endowed with a very important property free will. We choose to do what we want. The problem for a decart is that what we want is not just mental but often physical. We want things. We want to do things.

This means that these two separate realms, the world of matter and the world of mind must interact with each other. This is problematic. On the one hand, we know that matter influences mind. Right? In the classroom, I'll demonstrate this by walking up right to the big desk that's in the front of the classroom, which is often a laminated plywood top with metal sides. and I'll kick the side the desk really hard and the result is a huge reverberating metallic bang.

I'll then limp around the front of the room pretending to be injured. I ask what just happened and we see that there was a physical interaction body to body when my toes hit the desk and rapidly contracted from the force. But this rapid contraction of my toes had a seemingly non-material effect. It gave rise to an idea, a mental experience. At first, pain, then the thought, don't kick solid things, you idiot.

So, we have body-to-body interactions giving rise to a mental event, an idea, an experience. In the other direction, we have a sense that the mind influences matter. What I'll do then is I'll ask one of my students to please write the word guacamole on the top of his page of class notes. When completed, I ask the student why the name of this zesty avocado dip is scrolled in his notebook, and the response is usually because you asked me to. I then ask the student to stand up and flap his arms while clucking like a chicken.

Invariably, the student declines when I ask why. He says that he doesn't want to. So, the reason the word guacamole appears in the notes is not because I made you do it, but because you wanted to write it. Wanting, desiring, willing is a mental state. And somehow the idea in your head caused your hand to move in a very particular way that gave rise to exactly what you wanted to happen.

We do not often go to write a word and have a completely different word show up. Our minds seem to control our hand. So it looks like we have two completely different things material objects and ideas and they are different sort of entities right I can have a basketball and I can have the idea of a basketball the two are not the same one is material the other is mental one has size shape weight location the other doesn't round the idea of the basketball is the idea of a round orange But it's not an orange idea or a round idea. The properties of material and mental entities seem completely different. Yet the material seems to give rise to the mental through perception and the mental appears to give rise to the physical through acts of will.

We seem to have interaction between them. But how? It's the size, shape, and mass of one object that lets it act on another. If ideas have no physical properties, how can they give rise to physical movements like the hand moving the pen across the paper? This problem of interaction seems to plague the move to include non-material things in the universe to add a completely new category of stuff to reality. Decart tried to solve this problem anatomically. He knew that the brain was the bodily organ responsible for action.

So the mechanism by which the mind interacted with the world must reside there. He also knew that there's a network of nerves through the body that are in part responsible for taking data about the interaction of the world in the body back to the brain where they somehow gave rise to observation and were responsible for the movement of the muscles by the mind. So he figured that these nerves would be tubes much like the veins and arteries also criss-crossing the body. When veins and arteries carry blood pumped by the heart, these nerve tubes would carry a different fluid. Animal spirits that is spirits in the sense of a liquid, not spirit in the sense of a soul.

Although for Decart, soul, mind, and spirit would all have the same sense. It's through disturbances in the flow of the animal spirits that the mind would receive news of the physical world, send out its commands to the body. According to Decart's hypothesis, the part of the brain responsible for this is the pineal gland. A small part of the brain that had the twin virtues of being centrally located and Decart not having any idea what else it might be doing. It's through the manipulation of the animal spirits by the pineal gland that the mind connects with the body that we have the interaction between these two distinct parts of reality.

Now, turns out, of course, that this theory fails. We know that the nerves don't carry a subtle fluid and that the pineal gland is responsible for producing melatonin, a hormone that plays a crucial role in sleep and our bodily rhythms. But the central metaphysical question is still with us. Is there a single sort of thing in reality just material or is there some other sort of entity? For Decart, this other sort of entity was a soul and particular to humans. Animals he thought for theological reasons cannot have minds or souls.

Clearly Decart did not have pets. At Decart's time throughout Paris appeared hydraulic statues. Fountains that didn't just shoot out water but used the water pressure to move parts of the statues making up the fountain and so also making sounds like a collab. So from a distance Parisians would see human-shaped figures moving and playing music. They were animated like persons even though they had no mind.

Decard thought this is what animals were complicated automata complex organic robots. Over time the theology was weaned from the duelist view and living things were simply held to possess what French philosopher Henri Beran called an elan vital a vital force or vital impulse what the German thinker Arthur Schopenhau called the will to be. Living things have a will that non-living things do not. It's this will, this power to desire and cause to happen through internal means that separates the living in the universe from the non-living. The brain is relevant here.

It's necessary, but it's not sufficient. We could take a CAT scan and see that when we have certain kinds of thoughts, a certain area of the brain is active, right? When we have a certain sort of desire, a different section is engaged. When we have a certain sort of sensory experience, a completely different region lights up. We can absolutely conclude that there's a correlation between the state of the brain and a human experience. But the dualist will say that this correlation is a relation between two different things.

The materialist, someone who denies dualism, someone who contends that there's only one sort of metaphysical entity and that reality is strictly and solely material, must hold that brain states and mind states are the same thing, that they're different descriptions of the same occurrence. The dualist, on the other hand, holds that brain states and mind states are fundamentally different. We can point to the spot in the brain that's active when I feel pain in my stub toe. But the pain I feel, the experience of pain is not the same thing as the neural activity. The two are linked, but they're different according to the dualist.

They are one and the same according to the materialist. But consciousness for the dualist is completely different. It's non-material. One physicist who made this case was Eugene Vner. He was concerned with what we've seen in quantum mechanics as the measurement problem.

Okay, recall that the equation governing the development of quantum systems is the Schroinger equation. When a quantum system is is not observed, it occupies a state of superposition. That is, it's in a combination of every possible state it could occupy. The Schroinger equation describes how this superp position develops according to the potential energy in the environment of the system. But the instant we observe the system, it fails to be in the superposed state, but instead appears in one and only one of the possible states.

We can never predict which one it will be. The Schroinger equation gives us the odds that we'll find it in each of the possibilities. But the best we get is this probability. The problem here is that we have a physical law in the Schroinger equation that always holds except when we look. Physicists were bothered by three aspects.

One, how can you have a universal law of the universe that can be violated? Two, why is the violation subject to randomness? Right? This was Einstein's problem. And three, what is it about us looking at something that causes the violation? It's this third question that Eugene Vner tried to answer. One interesting thing about quantum systems is that they become entangled. Right? We talked about this earlier with respect to the identity of particles. Right? If two electrons bounce off one another, right? We may be able to label them as Bob and Carol coming in, but we can't say which one is Bob and which one is Carol coming out.

The best we could do is say one is now Ted and one is now Alice. Right? The two electrons cease to be independent things in the world that subsist and persist, but rather are just disturbances of a particular sort in the underlying field. When we talk about the behavior of the field, the reality of things themselves is lost. We say in this way that the parts of the system have become entangled and we can only describe the system as a whole. This is what makes the thought experiment called Schroinger's cat so troubling.

The idea is that we can easily create what are called spin correlated particles. Okay, electrons, for example, have a property called spin. Not that they're little ping-pong balls actually spinning, but the effect is much like what physicists recognize in angular momentum of a rotating charged object, right? A thing can be said to spin clockwise or counterclockwise. And there are different effects for each. Now, we can create pairs of electrons such that when we don't look at them, both are in superposed states of clockwise and counterclockwise.

But as soon as we observe one, both collapse into a single state of clockwise or counterclockwise such that one is always the opposite of the other. But we never know which will be which. It's the equivalent of a quantum coin flip. So attach the apparatus that creates these pairs to a spin detector that will observe the spin of one of these particles. Now attach the detector to a circuit connected to a poison gas canister such that if the detected particle is spinning clockwise, the circuit does nothing.

If the detected particle is spinning counterclockwise, the canister is opened, allowing the gas to escape. Finally, place the canister in a closed box containing a cat. Now we push the button. A correlated pair of electrons is emitted. The detector determines the spin of one.

If the electron collapsed from its superposed state into a clockwise spin, nothing happens and the cat lives. If the electron collapsed from its superposed state into the counterclockwise spin, then the detector sends the signal through the circuit. The gas escapes, the cat dies. But suppose we push the button and don't look in the box. The detector is made up of atoms.

It's a physical thing subject to the laws of quantum mechanics. If we've not observed the detector, its atoms will be in their superposed state which is now entangled with that of the emitted electron. the circuit likewise just more atoms which are unobserved and so they obey Schroinger's equation in a way that has them entangled with the state of the larger system and it's with the canister of gas and the cat assuming a picture of the cat like that of Decart in which the cat has you no mind capable of making observations right all of these are just atoms all of these unobserved and therefore all of these in superposed states in a grand entangled system. When we don't observe the system, it's in one big superposed state. Meaning the cat is in the superposed state of alive and dead.

It's not half dead. It's not in the process of dying, but rather it's in the superposed state of being both alive and dead. But the instant we open the door and look inside the cage, we see either a dead or alive cat. the wave function collapses into just one state. But wait a minute, we're just atoms too, right? We too should be part of the system as should the rest of the universe.

There should be no collapsing from the two superposed state into a single property state. Schroinger's equation should always hold in violet. Where is the only place in the process that a different sort of entity could be active? Vner concluded that the only place is in the making of the observation. An observation is when we learn of the result when our consciousness becomes involved. Other than our consciousness, there's nothing but atoms here and nothing that should affect the system to cause the collapse.

It's only our consciousness or perhaps that of the cat which we can find as fundamentally different here. Maybe like Decart we need to hold that there's matter and there's mind and the two are completely different but they interact. If this were true it would allow us to make sense of one of the most troubling aspects of quantum theory. But what sense do we then make of a non-material consciousness? And how does it cause the collapse of the wave function? It may answer one question, but it raises several others. Interestingly, quantum theory has been used in the opposite direction as well.

That is in support of materialism to give us a proposed material theory of consciousness. Sir Roger Penrose, the British mathematician and theoretical physicist, has argued that it's quantum effects that give rise to the sense we have of free will. dualism that there's more to reality than just matter and energy has to solve the problem of interaction. How do these two different sorts of things work with each other if they're completely different? Materialism has no such problem because there's only one kind of thing. But it has its own challenge, free will.

If the universe is just matter and energy and these behave according to well- behaved mathematically expressed laws of nature then we are just automa. We have no ability to do other than we do. We do not make choices. We have no ethical responsibility. We don't live the lives we think we live.

There are two possible approaches for materialists to take. First, they could try to save some sense of non-determinism in human action based on the laws of nature. They can try to argue that the universe is a well- behaved place, but that doesn't mean that human actions are a deterministic product of history and environment. The second approach is to give in on the question of free will, to accept that human actions are not the result of conscious deliberation, but to explain why they seem so much like they are. They have to explain away our sense of free will.

Now, Penrose takes the former line. He starts with the simple proposition that our actions are controlled by the brain which is made up of cells called neurons. All human actions, even the simplest movement, require an incredibly intricate choreography of neuronal activity. Neurons throughout the brain form intricate networks. Neurons work together by the release of chemicals called neurotransmitters that allow for the flow of electrical charge between them.

When one neuron releases a particular chemical into the gap between the cells, it will either facilitate or stop an exchange of electrical signals. And it's the propagation of these electrical signals through the brain that result in the bodily movement. Now, one part of the neuron that aids in the delivery of neurotransmitters are what we call microtubules. These are small thin tubes of a protein called tubulin. Their shape being long tubes and their presence in all neurons has led Penrose to consider that they may be more than just pipes.

It may be that the structure of the inside of the microtubules is such that it creates within the cell and then between cells an entangled quantum system. Being inside of a tube, this structure may be sufficiently isolated from the effects of the environment outside the body on the brain to remain at least for a while in a superposed state. This superposed state eventually is acted upon by the chemical environment of the brain causing the superposed state to collapse and the firing of a particular constellation of neurons. Because this process involves a necessarily quantum level process, there will be in this fully material system an element which is necessarily non-computable. In other words, the brain is nothing but a physical system working according to physical laws.

But because the structure of the brain is so fine, there may be a quantum level effect that makes our actions not determinable. We're governed by the laws of physics completely, but that does not mean that our actions or our intentions are uniquely determined by the environment and the absolute laws of the universe. Further, since the quantum states of these microtubules are coherent, that is entwined into a single system, it means that this sort of quantum consciousness involves the structure of the entire brain the way we would expect it to. So free will does not look like what we think it looks. It's not that we have a rational agency that has no dependence on the physical universe, but we're not robots acting at the whim of absolute physical rules either.

There's a controversy over this theory and whether findings in neuroanatomy are supporting or undermining the theory. However, the idea that quantum effects might be responsible for introducing indeterministic elements into the functioning of a material brain are one significant approach to trying to maintain the reductivist claim that what physics says there is is all there is. But one can hold that there are only material elements to reality and also hold that the mind is not completely describable by the laws of physics. Recall that reductionism buys into two different presuppositions. First that everything in reality is made up of atoms energy and the stuff of physics.

And second that the laws of physics are all that's needed to explain the behavior of these physical systems. Some thinkers accept the first but deny the second. That is, they hold that the ultimate constituents of the world are only things in the vocabulary of particle physicists, but that when you put them together in intricate ways, something new emerges from the structure and that it's greater than the sum of its parts in such a fashion that physics is insufficient to account for it. Mind, consciousness and life are emergent properties. That is, they involve nothing more than bits of physics, but become more than that when put together properly.

This view was championed in the first half of the 20th century by the Austrian sociologist, economist, and philosopher Otto Neuerat. Noat was quite the character, a huge hulking man with flaming red hair. He had a loud voice, a booming laugh, and a presence that announced him in any [clears throat] room he entered. Instead of a signature, he signed his letters with a a cartoon elephant, usually holding a flower in the trunk. Neuerat was not only a powerful figure in early 20th century social science, but a deep thinker about the place and power of science.

He believed that science education was essential to social advancement and good governance but worried that the language of science mathematics would be difficult for those who had to work and couldn't receive higher education. He thought that science could be communicated to the masses but it would require a new way of expressing mathematical relationships a new language which was visually evocative instead of using equations. The result was isoype, a picture language. Now, we all encounter isoype symbols every day. Walk to a public restroom and the figure out which is the men's room and which is the women's room by looking at the symbol.

That was no. Go to an intersection and know when to cross and when to wait. Those are isoype symbols flashing at the crosswalk. In theorizing about science, Noirat disagreed with his fellow thinkers in Vienna who were arguing the strict reductionist line. He was a sociologist and they were largely physicists.

Of course, they thought they held the key to all human knowledge. But physics, he thought, would never completely account for complex social interactions. Not that it was irrelevant, but that there needed to be more at higher levels. Scientific fields, he thought, were like balloons placed next to each other. Squeeze one and it expands, pressing into the ones next to them and reshaping them, causing them to push against those next to them.

Physics and chemistry share a boundary. And it's a squishy one that's influenced by pressures from both fields. But while one may help reshape the other, they are in the end separate balloons with their own subject matters, their own vocabularies and methods to study phenomena that happen at different levels. Chemical reactions are underneath nothing but the interplay of atoms with their various subatomic parts. But the complexity is in part due to the chemical structures that require a fundamentally chemical explanation with chemical concepts and chemical methods.

And so it is for biology, psychology, sociology, and economics. According to this view, the physicists may have given us all the furniture of the universe, but we can't have a complete understanding of reality if we don't pay close attention to how the interior decorator functions. It's not just the pieces we need to understand, but we'll redefine reality further if we understand what emerges from those pieces. And of all the aspects of the universe that emerge, perhaps none is more intricate, more fascinating, and more complicated than life.