Luboš Motl, March 11, 2015
The Preposterous Universe has promoted an old interview with Ed Witten about consciousness. I think that I agree with Witten’s points but I also tend to agree with Edward Measure’s feeling that much of the mystery is overhyped and filled with anthropocentric nonsense.
OK, so what is consciousness and should we explain it?
Don’t get me wrong, the very existence of consciousness is fascinating and I have spent lots of hours or days by thinking – and perhaps meditating – about this issue (mostly when I was 10 or so). The world could work just like the world around us but if there were no consciousness, like mine, the world would behave exactly as if it didn’t exist at all. No one would know about the complicated dynamics or really «feel» how amazing it is. So there seems to be something «extra» added on top of the physical laws, I used to emphasize.
These days, I would emphasize that one must carefully avoid some obvious traps when we want to discuss consciousness in an intelligent way. First, we should separate the «technical knowledge» about the working of the brain etc. from the spiritual dimension.
I have effectively said that we must separate the «brain» from the «soul» and you could interpret it by suggesting that souls are flying away from our bodies and they live their independent lives. Well, I don’t really want to claim those things. Souls and consciousness depend on something we call a material carrier, something that can be accessed by natural science. But we still feel that there’s something else on top of it that science hasn’t explained.
What are these layers?
Well, we believe that most of our consciousness – and thinking – takes place in the brain which is a piece of meat inside our heads.
(If you’re not a regular TRF reader, I must also tell you that the head is the ball sitting on your neck. A ball is anything resembling the object that the girlfriend killer Oscar Pistorius and the famous Czech entrepreneur, gangster, and fugitive Radovan Krejčíř use to play soccer in their South African VIP prison. Radovan has clearly won the match.)
The brain contains neurons that communicate by some electric impulses and at some vague level, it operates as a computer. There are lots of important differences between the human brain and the silicon-based, von-Neumann-architecture-designed computer. Neuroscience studies lots of these things and is improving our collective knowledge and understanding of these mechanisms. We also understand something – and hopefully a growing something – about the way how the brains evolved during evolution, and so on.
For our brain to be as impressive as it is, it has to contain some memory, CPU units able to calculate and evaluate the information, and it has to be connected to some senses that collect the information in the real world as well as things like muscles that allow the brain to influence the environment. Those features make it analogous to an electronic device. Unlike a typical computer program, our brain doesn’t seem to be fully deterministic. The very fact that we don’t know in advance «what the brain can do and how» is naturally linked to the human brain’s creativity.
But the neural networks may be emulated and experts are increasingly understanding this «special kind of a device» just like others are understanding the inner workings of devices we have constructed.
In principle, all this wisdom may be reduced to the fundamental laws of physics. The laws of quantum mechanics – and QED, the Standard Model, or string theory – apply not only to one elementary particle or one atom or one molecule. They apply to any bound state. We may calculate the probability that a particular object prepared in some initial state will do something or something else in the final state, and so on.
In principle, we may use quantum mechanics to calculate that someone will say something, e.g. «wow, I am conscious». We may use it to calculate his level of hormones and because we know how hormones influence our feelings, we may extrapolate this relationship and guess what the other people are probably feeling right now.
But there still seems to be a mysterious, probably permanently inaccessible layer of mystery.
We’re not really sure whether they feel the same thing as we do. We’re not sure whether they’re feeling anything at all. We’re not sure who or what has any consciousness at all. And what the boundary between the consciousness and the rest is. And we don’t know why «we» – and every reader could apply «I» individualistically to herself – are aware of anything at all. Critics of science love to say – and we tend to agree – that science is too weak to answer such questions.
Well, we add that it may look like a weakness but the science’s avoidance of similar hopeless questions is actually a part of its strength! Scientific research (at least that of good scientists) is focusing on questions that are sufficiently ambitious but also sufficiently down-to-Earth so that the goal to crack the mystery isn’t hopeless. There is an optimal point in between and various people are erring on both sides. (I think that the previous sentences are almost exact quotes by Andy Strominger but I believe I said the same things before I heard them, too.)
OK, let’s try to answer questions such as «who is conscious and who is not».
First, I know that I have consciousness even though you may think (if you’re a «solipsist») that I and all other people are just dull robots without any soul. You are only sure about your own consciousness. Do I think that others have consciousness as well? Well, I would carefully say that I think that the perspective in which they do have it is perfectly sensible scientifically (but it isn’t necessarily the only scientifically solid way to approach these matters). The reason is evolution – common ancestry etc. We are qualitatively the same «gadgets» so if I know that I am conscious, of course that I should admit that others are self-aware, too. The differences between me (read it as your name, if you wish) and others are not so dramatic.
Many questions about the soul and consciousness may be murky but there’s a lot of science that is not murky and biology and evolution belongs to this solid science. If you believe the idea that you are qualitatively different than everyone else – so that one has to assume that no one else may have consciousness, no one else may describe Nature from the same subjective viewpoint as you do – then you contradict some of the basic pillars of this hard science.
However, I am not saying that you may «directly verify» that others have consciousness. You are only verifying the things that even deterministic robots are able to do. This doesn’t really prove that other people «feel» something in the same way as you do. At the same moment, I must emphasize that quantum mechanics is really supposed to be used in the subjective way – the observer (the user of quantum mechanics) views himself as the only conscious entity and everything else is the «external world» that evolves according to the basic equations of quantum mechanics and that may be measured. The probabilities of different outcomes may be predicted. However, this subjective character of the physical description of Nature effectively disappears when we get at a certain macroscopic level.
Fine, do the other people have exactly the same feelings when they’re exposed to the same stimuli and the same idea?
The answer is almost certainly that the feelings can’t be the same. Take the eyes. You look at the blue-violet shirt on the photograph and you have certain feelings. You were trained to say that the two colors are «blue» and «violet». Other people who were also trained say the same two words, if they’re serious, or the analogous words in other languages.
But can’t other people see the left photograph exactly in the way in which you see the right one, and vice versa (I originally wanted the cyclic permutation of the red-green-blue channels but the negation is good enough)? A different person may actually see «brown and green» instead of «blue and violet». But he has learned to use the word «blue and violet» for these «brown and green» feelings, so he ends up saying things that suggest that the two of you are feeling the same thing when they look at the photograph. But maybe you are seeing something completely different.
By design, I have talked about the «truly spiritual» layer of the perceptions that will always be inaccessible to experimental tests. If I conjecture that someone has totally different feelings than you do but all the feelings are permuted and reparameterized when you want to listen to the person or observe him in any other way, well, then the conjecture can’t really be falsified.
Maybe it’s unnatural to say that other people see «light as dark» and «dark as light» and in many similar situations, one may cut this «people perceive things differently» idea by Occam’s razor. But I am pretty sure that this idea that can’t really be falsified – that different brains are feeling and doing completely different things when they are exposed to the same stimuli or before they end up with the same result of a calculation – is actually true for a majority of the stimuli and thinking. Different people are almost certainly organizing the visual and other perceptions and ideas in different ways. Sometimes the differences are modest, sometimes they are huge, but they are never zero. As Feynman has said, people are also doing very different things in their brain when they calculate something or answer a question and a special big layer of our brains translates the idiosyncratic methods to whatever may be communicated to others.
I began to converge to the questions «what it looks like» and «what the people will tell you» which are a part of science or physics, as I have said. My main point is still the same: If you dismiss these questions as technicalities that are not too spiritual, well, then you have drawn a clear boundary and the «important, spiritual aspects of consciousness» are exactly those that science simply cannot access, by definition!
Fine. Let’s admit that just like you have consciousness, you should admit that other men and perhaps women, chimps, and other mammals are conscious as well (feminists will surely forgive my ordering of the agents which wasn’t supposed to convey an idea). To claim otherwise really means to deny evolution. Squirrels may have poorer memory and abstract skills, ability to compute and generalize ideas etc., but this inferiority may be classified as «just another technicality».
When it comes to the truly metaphysical, qualitative aspects of consciousness, squirrels simply have to be analogous to humans because all of us have common ancestors, too (and we’re composed of similar and similarly interconnected cells). To claim that squirrels aren’t conscious means to deny evolution and most of biology, too. There just can’t be a truly metaphysical difference between squirrels and humans.
We shouldn’t stop with squirrels. Biology teaches us that there’s nothing metaphysically different about mammals and there is nothing God-like about our common ancestors (including Jesus Christ if he or He existed, sorry), either. Birds or dinosaurs have to be self-aware, too. They don’t know how to manipulate with the information they are aware of too well but in principle, they must enjoy the analogous spiritual dimensions of consciousness as we do. They really feel well during a nice sunny day, too.
Needless to say, it doesn’t end up with animals. Bacteria, plants, or fungi can’t be too different. And the same comment must apply to «not living» objects because they don’t differ «metaphysically» from the organisms, either. So they must have the same potential to be aware of any information that is available to them.
Two months ago, after an interactive black hole talk in Prague, I made similar points and discussed the extreme case of the conscious hydrogen atom. She is peacefully sitting in space with the electron in a state of motion. She must be aware of the good feeling of sitting in the \(1s\) ground state, right? When a photon hits her electron, the electron may get excited and she feels some pain or arousal – unfortunately, there is no fully accurate noun in English to describe the feelings of a hydrogen atom (because not too many atoms speak English as their mother tongue) – associated with the \(2s\) or \(2p\) state.
Well, one must be careful here (and almost everywhere). The hydrogen atom is tiny and quantum mechanical effects are maximally strong here. You can’t assume that the hydrogen atom has sharp feelings about its state – because it can’t really measure itself all the time. To measure an object or an observable and to convert the measurement to classical information, you need a macroscopic number of degrees of freedom that allow the nearly classical copying of the information and decoherence.
I still think that it’s fair to say that even the hydrogen atom has consciousness. The inability to quickly decohere and convert the quantum bits to classical bits may be interpreted as the hydrogen atom’s being drunk. The information that she is aware of may be inaccurate, resembling the hallucinations that people may have when they are drunk or high. When the hydrogen atom re-interferes and requires us to retroactively state that some «weak» measurement of the intermediate state couldn’t have been right, it’s just a proof for the hydrogen atom that she suffered from a hallucination. The more macroscopic and solid an observer is, the more capable of avoiding such hallucinations he becomes.
To combine this discussion about consciousness with the foundations of quantum mechanics is a lot of fun. Also, I need to point out that it’s ironic that so many people have a problem with the insight that quantum mechanics calculates its predictions that are meant to be evaluated by conscious observers; and so many people – sometimes the same people – also feel anxious about the fact that science can’t address consciousness. As far as I can say, these two problems don’t quite cancel but within quantum mechanics, they reduce just to one assumption. Quantum mechanics surely needs observers who subjectively divide everything into their perceptions and the external world. Everyone who agrees that consciousness exists (because he has it) should also agree that its existence is an uncontroversial assumption. It is not absurd for quantum mechanics to use conscious observers as the final arbiters of measurements – after all, many of us do know that the consciousness does exist so the assumption that it does shouldn’t be assaulted or humiliated. Measurements that are subjectively perceived at the end weren’t needed to formulate the classical laws but these perceptions do exist and newer, quantum laws simply do require these perceptions for the laws to be properly formulated. These sentences always tend to sound more spiritual or religious than they should be but it’s true that while classical physics described how «things objectively are at every moment of time», quantum mechanics probabilistically predicts «what an observer who uses the theory will perceive only when he actually does», while this new framework of physics is claiming that the «objective information» before the subjective measurement (or perception) is non-existent or ill-defined or scientifically meaningless.
But even if we forget about the consciousness of microscopic objects, we face the question whether computers or cars are self-aware. Well, my answer is that they must also be considered self-aware. They’re just unable to feel and manipulate with lots of information, or at least they don’t know how to do so «freely» in a way that makes the final decisions rather uncertain at the beginning. And that is why their consciousness feels much less «rich» than ours. But in principle, it’s there as well. A microprocessor is aware of the numbers stored in its registers and other things. There is no metaphysical, truly qualitative gap between living organisms and inanimate objects.
I’ve said that most of the time, we define the «truly deep and spiritual aspects of consciousness» as those that can be seen to be inaccessible to science, pretty much by definition. Some people may view it as a limitation of science; others may view it as a strength of science – the ability to focus on meaningful questions. Some of the oldest questions about consciousness will be inaccessible to science forever – and it’s no reason for science or scientists to be ashamed.
But there’s a complementary way to argue that the claims that «science is limited because it can’t address consciousness» are irrational. When one tries to discuss these matters and e.g. analyze the evidence for or against the question whether the hydrogen atom is conscious, the people who love to talk about consciousness start to behave as if you have said a heresy. The hydrogen atom isn’t even alive, so it can’t be conscious, you often hear, not to mention lots of similar claims.
But what’s the evidence that an object that is not alive in the usual sense can’t be conscious? If one wants to discuss questions rationally, one must avoid these old religious dogmas, stereotypes, and superstitions – e.g. that the soul is particularly connected with something that resembles a human. In science, one can only believe some claim if there is some actual evidence and the habit of people to link consciousness with humans contains zero evidence. If you want to address a question really rationally and scientifically, you must be ready that some of your unproven assumptions will be shown to be false (sharply or at least by a body of inconclusive evidence).
Even though I have said that I agree that there’s some level of consciousness that lies beneath all the structure that may be analyzed scientifically, I would probably never try to enter «research» into these matters (beyond the comments in this blog post) because 1) I don’t think that the people who are obsessed with the concept of consciousness are acting or thinking rationally or honestly, in the scientific sense, and they would appreciate some important realizations even if one managed to find them, and 2) I really feel that the «bare spiritual consciousness» has no structure or patterns and it is only the structure or patterns that deserve our (or my) scientific brains’ CPU time.
Consciousness in the deepest spiritual sense «exists» but that’s everything one can say and one should say about it! The fascinating spiritual dimension of consciousness should be lived rather than studied.
And that’s the memo.