Physics of Consciousness - Max Tegmark

Max Tegmark - Cosmology

Max Tegmark

Max Tegmark is Professor of Physics at Massachusetts Institute of Technology. He holds a BS in Physics and a BA in Economics from the Royal Institute of Technology in Sweden. He also earned a MA and PhD in physics from University of California, Berkeley.

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Max
Tegmark

Physicist, MIT

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Robert Lawrence Kuhn:

Max, for the last half century, I've been focusing on consciousness. I did my doctorate in neuroscience and the assumption was that physics, sure, was the underpinning of the chemistry and the biochemistry and the cellular structure, but we didn't have to worry about that or even think about it to understand the nature of consciousness. That has changed recently. Why so? Why is the physics of consciousness particularly important?

Max Tegmark:

I feel that it's changed because we've come to realize that a large fraction of the things we're stuck on in physics, of unsolved mysteries, actually have to do with what it means to be an observer. If you take, for example, the biggest embarrassment of all, that we can't unify general relativity, the theory of the big, with quantum mechanics, the theory of the small. These two theories have the exact opposite definition of observer. General relativity says an observer is this infinitesimally tiny thing with no mass and having no effect on its environment.

Robert Lawrence Kuhn:

A point, yeah.

Max Tegmark:

Yeah, whereas quantum mechanics says that the observer has an effect on that which is observed, so no wonder we can't unify them. There are a lot of other problems too, where if you trace back, in my opinion, where the rub lies. It's the fact that we've tried to avoid talking about what an observer is, even though physics is supposed to be the subject of observation, which is ridiculous. There's been this kind of prejudice that consciousness is just a bunch of flaky hooey that physicists shouldn't talk about and that we can somehow get away with not talking about it. And I think we have to face up to the face that, no, especially if you believe that I am made of quarks and electrons and physical things, I can't sweep under the rug the fact that I am an observer and if I want to know what observers see, I have to understand the relationship between quarks and electrons and this subjective ...

Robert Lawrence Kuhn:

So it's one thing to say that something about consciousness has to be imply...imbued in our physics to understand in one way or another. It's quite another to say that the physics, therefore, then helps us to understand what consciousness, this phenomenal inner experience that we have that, you know, I know I have and I think you have, but I can't be quite sure...

Max Tegmark:

Are you calling me a zombie?

Robert Lawrence Kuhn:

This inner feeling that we have, which seems so remarkable. So how can physics then recursively explain consciousness?

Max Tegmark:

Because it forces us into making the question a little bit easier. If you take the famous hard problem of consciousness you articulated, namely why is it that this quark blob has a subjective experience, that feels very hard. but if you take a starting point that some quark blobs, like this one, have this subjective experience and other ones, like this table, don't, then this transforms this hard problem into this hard fact that some quark blobs are conscious, some aren't, so there must be some physical principle, some equation which tells you which things are conscious and which aren't, and this becomes now an experimental question. You can put me in our magnetoencephalography scanner at MIT and measure information processing in my head, and I can have a computer program that shows me in real time whether I'm thinking about a strawberry or a chair on a computer screen and I also know subjectively what I'm thinking, so I can check if that's correct or not and then I can start to say, well, okay, the computer has this particular part of the information processing membrane that I'm conscious of, the computer sees, but the computer also sees some information processing that I'm not conscious about, like my heartbeat regulation. So what principle is it that distinguishes consciousness from unconscious information processing? I am convinced...this is a radical...this is a controversial point of view, but I'm convinced that there is some principle, some equation that determines which kinds of information processing are conscious and which aren't, and I would love to find it.

Robert Lawrence Kuhn:

Well, that would certainly be a remarkable achievement, but what you're assuming when you see correlations in the brain with, with phenomenal experience, is certainly a correlation, but the question is causation and what is called identity theory. Are you saying that those electrical activity, whatever they are, that equation is, is exactly the same thing as the phenomenal experience? Like you say Venus is the morning star and the evening star, I mean, using two different terms for exactly the same object. Is that what you're saying, that the equation you want to find is? Because if you're saying that, that seems like a category mistake, because how can you say an equation is this feeling that I have?

Max Tegmark:

My guess is that the subjective experience that we call consciousness is the way information feels when being processed in certain complex ways, and I feel I'm kind of forced into guessing this from the starting point that I think it's all physics. I'm not allowed to have any extra secret sauce to add to it. And that makes it much harder for me, but at the same time, it limits it down to this very concrete problem that I have to ask. There is clearly some additional principle about information processing in nature that distinguishes between the conscious kind and the unconscious kind, and I would love to find it. This isn't just philosophically fascinating, but it's important too. You know, suppose you are an emergency room doctor and you have an unresponsive patient there. Wouldn't it be great if you could somehow have a machine that told you whether that patient was conscious? In the future, suppose we build extremely advanced artificial intelligence that we can have conversations with. Wouldn't we like to know if the thing is just a zombie pretending to have emotions, without feeling like anything, or whether it's actually conscious and we should feel guilty about switching it off?

Robert Lawrence Kuhn:

And do you feel that is possible in principle? Because I'm really a skeptic on that.

Max Tegmark:

Well, if my guess is right, that there's a unity in the sense that physics ultimately applies to everything, then there is such an answer out there and we don't know that we're smart enough to find it, but the safest way to fail in this is to convince ourselves that it's impossible and not to try, so that's why I'm trying so hard.