Translator: Maria K.
Reviewer: Denise RQ Consciousness - we've all wondered about
the mystery of consciousness. But there are really
two separate mysteries, as the famous philosopher
David Chalmers has emphasized. First, there is the mystery
of how our brain processes information, which David calls, "the easy
problems of consciousness," and even though they're
actually very hard, we've made huge progress in recent years
building computers that can play chess, that can process natural language,
that can answer quiz show questions, that can drive cars, and so on. But then, there is a second
mystery of consciousness that David calls,
"the hard problem of consciousness." Why do we have subjective experience? If I'm driving a car, I'm having a subjective experience
of colors, of sounds, emotions, thoughts. But why? Does a self-driving car
have any subjective experience? Does it feel like anything at all
to be a self-driving car? Raise your hand if you have
any sort of background in physics. Uh, some wolves
in sheep's clothes here tonight. I am a physicist, too. from my physics perspective, a conscious person
is simply food rearranged. So, why is one arrangement conscious
and not the other? Moreover, from my physics perspective, food is just a bunch
of quarks and electrons arranged in a certain way, so why is one arrangement,
like your brain, conscious while another arrangement,
like a bunch of carrots, not? This physics perspective
goes against the idea that philosophers like to call dualism, that conscience is explained
by adding something beyond physics, some extra ingredient,
a life forest, elan vital, or a soul. This idea of dualism has gradually
lost popularity among scientists, because if you were to measure what all the particles
in your brain are doing and find that they perfectly obey
the laws of physics, then that would mean that this purported soul is having
absolutely no effect on what you're doing. Whereas, if you were to measure instead that these particles in your brain
are not obeying the laws of physics, because they're being pushed
around somehow by the soul, then that brings the soul
into the domain of physics. Because you can now just measure
all these new forces the soul is exerting and study the properties physically of it
just as you would study the properties of a new field or a new particle
like a Higgs boson. From my physics perspective, a bunch of moving quarks
and electrons are nothing but a mathematical pattern in space-time. A bunch of numbers specifying positions,
and motions, and various properties of these particles like electric charge, and other numbers
you can see in this table here. From this physics perspective,
that hard question of consciousness that David Chalmers posed gets transformed
into a form I like much better. Because we can now start, instead of starting
by asking the hard question of why some arrangements
of particles feel conscious, we can start with a hard fact. That some arrangement of particles
like your brains, are conscious; and not others. We can ask, "What are
these special physical properties these arrangements
have to have to be conscious?" Neuroscientists have had a lot of progress
recently, including right here, in figuring out what subjective
experiences correspond to different neuron firing patterns
in your brain, which they call
neural correlates of consciousness. I want to generalize this idea and ask what subjective experiences correspond
to different kind of particle motions, which you might call
physical correlates of consciousness. But before that, this whole physics perspective
really begs the question: how can something
as complicated as consciousness possibly be explained
by something as simple as particles? I think it's because consciousness
is a phenomenon that has properties above and beyond
the properties of its particles. We physicists call phenomena that have properties
above and beyond those over their parts: emergent phenomena. Let me explain this with an example
that's simpler than consciousness: wetness. A water droplet is wet, but an ice crystal
or a gas cloud is not wet even though they are made
of the exact same kind of water molecules. So, it's not the molecules, it's not the particles
that make the difference; it's the pattern
into which they are arranged. So it makes no sense whatsoever to argue about whether
a single water molecule is wet or not, because the phenomenon
of wetness only emerges when you take
a vast number of water molecules and you arrange them
in this special pattern we call liquid. So solids, liquids, and gases
are all emergent phenomena in that they have properties
above and beyond those that are particles, they have properties
that the particles don't have. I think that just like solids,
liquids, and gases, consciousness too
is an emergent phenomenon, because, if I drift off into sleep,
and my consciousness goes away, I'm still made out
of the exact same particles. The only thing that changed is the pattern
into which my particles were arranged. And if I were to freeze to death, then, my consciousness
would definitely go away, but I would still consist
of exactly the same particles. It's just that they were now rearranged
to make me rather an unfortunate pattern. (Laughter) So we physicists love studying what happens when you take
a lot of particles, and you put them together
in different patterns. We love to study what properties emerge; and often, these properties are numbers
that we can just go out and measure like how viscous something is,
how compressible it is, and so on. We can use these to classify stuff. For example, if some stuff is very viscous
so it's rigid, we call it a solid. Otherwise, we call it a fluid. If the fluid comes really hard
to compress, we call it a liquid. Otherwise, we call it a gas or a plasma
depending on how it conducts electricity. So, could there be
some other number like this that quantifies consciousness? That's exactly what
the neuroscientist Giulio Tononi thinks. He's defined such a quantity
that he calls integrated information, Phi, which is basically a measure of how much different parts of a system
know about each other. He and his colleagues have managed to measure a simplified version
of this quantity using EEG after magnetic stimulation, and it's worked really, really well
this consciousness detector of theirs, managing to identify consciousness in patients that are awake
or who are dreaming, but not patients who are anesthetized
Or who are in deep sleep. They even correctly identify consciousness
in two patients with Locked-in syndrome, paralyzed, and totally unable
to communicate in any way. So this is potentially very useful
for doctors in the future. But I want to generalize this now
to non-biological systems, as well. For example, we can ask the question
of some future super-intelligent computer: is it conscious or not? To do this let's look at systems, let's look at states of matter
with emergent phenomena that have something to do
with information. To store information
has to have the physical properties that have some states
that are just very long-lived. Most solids will do for this,
like my wedding ring, for example; if I engrave my wife's name in this medal, this information
will still be there years from now, but if I instead engraved it
in a puddle of water, the information
will be lost within seconds. For a more fun example, let's look at computronium,
which is the name given to the most general substance
that can compute. There is not enough for it
to be able to store information, but it also has to be able
to process information. The laws of physics have
to make a computronium change over time in a sufficiently complicated way that it can implement
arbitrary information processing schemes. Let's define perceptronium also
as the most general substance that's conscious,
that has a subjective experience. And let's ask what properties does
this perceptronium have to have? I think that it has to have, first of all,
the same properties as computronium, but at least one more property
that I want to get back to. But first, we just have to ask ourselves how can something as physical
as a bunch of moving particles possibly feel as non-physical,
as our consciousness? I think it's because our consciousness
is a phenomenon that doesn't only have properties
above and beyond those of its parts, but also has properties
that are rather independent of its parts, independent of its substrate, independent of the stuff
that it's made of. We actually have
other phenomena in physics that are also substrate-
independent in this sense. For example, waves. Waves have properties like wavelength,
and frequency, and speed, and we can describe them
really, really accurately with equations, even without knowing
what kind of substance are waves in. So these waves take
their life on their own above and beyond the substrate. For example, a wave can cross a lake
even though the individual water molecules are just going around
in tiny little circles. Computation is also
rather substrate-independent, because Alan Turing famously proved that any computation
can be performed by any substance as long as it has a certain minimum set
of abilities to compute. So this means that if you were
a self-aware computer game character trapped in your game-world in some game
in a future super-intelligent computer, you will have no way of knowing
whether you are running on Windows, a macOS
or some other platform, because you would be
substrate-independent. I think consciousness is the same way. I think consciousness
is a physical phenomenon that feels non-physical, because it's just like waves
and computations. More specifically, I think that consciousness
is the way information feels when it's been processed
in certain complex ways. So this means
that it's substrate-independent, and this also means
that is only the structure of the information processing
that matters, not the structure of the matter
that's doing the information processing. In other words,
we have the laws of physics. They govern these motions of stuff. If the motions obey certain principles, we can get these emergent phenomena
of computation: information processing. But now we can take this idea
to another level. We can say, "Suppose this information processing
obeys certain principles, then we can get higher level
emergent phenomena: consciousness. What would these principles be? We, of course, don't know what sufficient conditions are
for a physical system to be conscious, but let me tell you
about four necessary conditions that I have explored in my work. I've already argued
that consciousness is the way that information feels
when it's being processed, so for a physical system to be conscious, then, first of all, it has to be able
to store information like a computer, and it has to be able
to process information like a computer. But also, I think, it needs to be relatively independent
of the rest of the world, because otherwise,
this conscious entity would not feel like it had any sort
of independent existence at all. And finally, like Giulio Tenoni argued,
I think that this system has to be relatively integrated
into a unified whole, because otherwise,
if you have two independent systems, then this is going to feel
like two separate conscious entities rather than one. What do we make of this idea then, that consciousness is the way information
feels when being processed by particles moving around
in certain ways? Is it good news or is it bad news? I think it's good news. If someone argues that it's bad news because they don't like the idea
of being just a bunch of particles, then I object to their use
of the word 'just, ' because let's face it: you guys are not just
a bunch of particles. Your brains are the most
beautifully complex space-time patterns in our entire known universe. And moreover, as I've argued, your consciousness has properties
above and beyond those of your particles that are in fact rather independent
of your particles. So it's not the particles,
but the patterns that really matter. I also think this is good news because it means that in our quest
to understand consciousness, we are not stuck waiting
for some missing ingredient. This is really about asking
the right question. And instead of asking,
"Ah, we're stuck, you know? So what missing thing
can we blame our failure on?" Let's instead ask the question,
"Might it be, despite how it all seems, that we already have all the ingredients
we need to solve our problem?" I think this question is actually
a very powerful one, both in science
and in our every day lives, and I hope you'll try it out yourselves. For example, people used to ask, "What new undiscovered force
prevents the Moon from falling down?" "Nothing," Isaac Newton came along and said. "The Moon obeys the same laws of physics,"
he said, "as everything else," and this bold idea, of course
revolutionized modern science. Then you can ask, "What is it that breathes life
into a clump of atoms and makes it alive?" Again, scientists have discovered
that the answer is, "Nothing," because the difference
between a dead bug and a living bug isn't that you add
some sort of secret life sauce to it. It's simply the pattern into which
the particles are arranged that matters. Then you could ask, "What breathes fire
into an information processing system and makes it conscious?" I've already argued here tonight
that again, the answer is, "Nothing," because what matters is simply the structure
of the information processing. And finally, if our entire cosmos
turns out to be perfectly described by physical laws
like modern physics suggests, then we can ask
Stephen Hawking's famous question, "What is it that breathes fire
into a mathematical structure and makes a universe for it to describe?" I've argued the consciousness
is a mathematical pattern which means
that some mathematical patterns simply are conscious, which means that the answer
to this question is also, "Nothing," because the only difference then between a structure
that exists only mathematically and one that also exists physically is not the presence of some sort of
physical existence, magical, angel dust. It's simply its structure. So here is the idea that I would like you
all to take with you tonight: instead of asking what do we need to add to physics
to explain consciousness, consider the idea that maybe
we don't need to add anything at all; that because consciousness
is simply the way information feels when it is being processed
and turn in complex ways by particles moving around
in very special patterns. And let us instead ask, "What are these patterns?
What are their physical properties?" Because it's not the particles,
but the patterns that really matter. Thank you. (Applause)
"Conscious" is used as "a human body which can track a finger with its eyes and can answer correctly when asked how many fingers are raised" in certain professions or as "didn't wake up screaming during the operation". Math/physics/computer science people coming up with formulas for what kind of patterns/matter organization/computations are conscious aren't doing anything different from this type of usage.
They simply establish more sophisticated criteria by which to distinguish between etalons: the functioning brain, the sleeping brain, a cabbage.
This isn't touching the hard problem at all, which wants to talk about what consciousness is really, that is, apart from all the ways in which the word is used in practice, so, a priori apart from the practical success of mathematical formulas proving able to distinguish between what we usually call "conscious" and "unconscious".
I'm confused.
Does a majority on this board not believe that the entirety of your thoughts are computed by your brain?
Considering we have a factorial of 100 trillion possible arrangements of synapses in our pattern, I don't see us capturing it easily in an easily described equation.
That doesn't mean the equation doesn't exist, but we might not have the hardware to interpret or solve it.
Max Tegmark here: contrary to what's said on this thread, I'm certainly not arguing that consciousness is an illusion! (In contrast, Daniel Dennett does.) IMHO, consciousness is the only thing we really have first-hand knowledge about. I'm instead arguing that it's produced by physical processes (particles moving around, etc.), not by the addition of some non-physical extra ingredient such as an elan vital or soul.
oh no. tedx.
great way to circumvent peer review and all that.
reminds me of that time Ted freaked and attempted to censor a real foray into the nature of consciousness
Mathematics, in its abstract nature, can be used to describe just about anything, but saying that what you're describing is itself the abstract description is just flat wrong unless that something itself is an abstraction. The circle I draw on a whiteboard is not the parametric formula for the circle, and consciousness is not any mathematical system which attempts to describe it.
The idea of consciousness as an emergent property is a powerful one that I've been contemplating for a while. While everything around us that we can measure is physical it is possible there are levels of existence that are non-physical which cannot be measured as easily. So consciousness could really just be a projection of a higher dimensional object into lower dimensional space. Like making a 2-dimensional horizontal slice through a donut and only seeing two separate circles. We know we are conscious, and we are fairly certain that there is a physical world, yet we don't have a broad enough perspective to see how they are connected and that they are really part of the same thing.
This is my main problem with Tegmark's mathematical universe theory: math is a symbolic system of description developed by observing the physical world for the purpose of explaining the movements of the physical world. Yet we cannot penetrate through the fabric of that world to actually see whether it is created by math rather than just being described by it. It could very well be that mathematics such as they are break down or become contradictory if it is attempted to use them to describe these other dimensions. Perhaps reality is made of information, as Tegmark suggests, but rather than being digital information it is purely analog.
Given the plethora of bad explanations of consciousness that receive massive upvotes, my guess is that there are tons of people out there really hoping that the hard problem of consciousness just disappears.
It's not that this research isn't useful, but it doesn't answer what consciousness is.