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Cake day: July 7th, 2024

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  • What is it then? If you say it’s a wave, well, that wave is in Hilbert space which is infinitely dimensional, not in spacetime which is four dimensional, so what does it mean to say the wave is “going through” the slit if it doesn’t exist in spacetime? Personally, I think all the confusion around QM stems from trying to objectify a probability distribution, which is what people do when they claim it turns into a literal wave.

    To be honest, I think it’s cheating. People are used to physics being continuous, but in quantum mechanics it is discrete. Schrodinger showed that if you take any operator and compute a derivative, you can “fill in the gaps” in between interactions, but this is just purely metaphysical. You never see these “in between” gaps. It’s just a nice little mathematical trick and nothing more. Even Schrodinger later abandoned this idea and admitted that trying to fill in the gaps between interactions just leads to confusion in his book Nature and the Greeks and Science and Humanism.

    What’s even more problematic about this viewpoint is that Schrodinger’s wave equation is a result of a very particular mathematical formalism. It is not actually needed to make correct predictions. Heisenberg had developed what is known as matrix mechanics whereby you evolve the observables themselves rather than the state vector. Every time there is an interaction, you apply a discrete change to the observables. You always get the right statistical predictions and yet you don’t need the wave function at all.

    The wave function is purely a result of a particular mathematical formalism and there is no reason to assign it ontological reality. Even then, if you have ever worked with quantum mechanics, it is quite apparent that the wave function is just a function for picking probability amplitudes from a state vector, and the state vector is merely a list of, well, probability amplitudes. Quantum mechanics is probabilistic so we assign things a list of probabilities. Treating a list of probabilities as if it has ontological existence doesn’t even make any sense, and it baffles me that it is so popular for people to do so.

    This is why Hilbert space is infinitely dimensional. If I have a single qubit, there are two possible outcomes, 0 and 1. If I have two qubits, there are four possible outcomes, 00, 01, 10, and 11. If I have three qubits, there are eight possible outcomes, 000, 001, 010, 011, 100, 101, 110, and 111. If I assigned a probability amplitude to each event occurring, then the degrees of freedom would grow exponentially as I include more qubits into my system. The number of degrees of freedom are unbounded.

    This is exactly how Hilbert space works. Interpreting this as a physical infinitely dimensional space where waves really propagate through it just makes absolutely no sense!


  • i’d agree that we don’t really understand consciousness. i’d argue it’s more an issue of defining consciousness and what that encompasses than knowing its biological background.

    Personally, no offense, but I think this a contradiction in terms. If we cannot define “consciousness” then you cannot say we don’t understand it. Don’t understand what? If you have not defined it, then saying we don’t understand it is like saying we don’t understand akokasdo. There is nothing to understand about akokasdo because it doesn’t mean anything.

    In my opinion, “consciousness” is largely a buzzword, so there is just nothing to understand about it. When we actually talk about meaningful things like intelligence, self-awareness, experience, etc, I can at least have an idea of what is being talked about. But when people talk about “consciousness” it just becomes entirely unclear what the conversation is even about, and in none of these cases is it ever an additional substance that needs some sort of special explanation.

    I have never been convinced of panpsychism, IIT, idealism, dualism, or any of these philosophies or models because they seem to be solutions in search of a problem. They have to convince you there really is a problem in the first place, but they only do so by talking about consciousness vaguely so that you can’t pin down what it is, which makes people think we need some sort of special theory of consciousness, but if you can’t pin down what consciousness is then we don’t need a theory of it at all as there is simply nothing of meaning being discussed.

    They cannot justify themselves in a vacuum. Take IIT for example. In a vacuum, you can say it gives a quantifiable prediction of consciousness, but “consciousness” would just be defined as whatever IIT is quantifying. The issue here is that IIT has not given me a reason to why I should care about them quantifying what they are quantifying. There is a reason, of course, it is implicit. The implicit reason is that what they are quantifying is the same as the “special” consciousness that supposedly needs some sort of “special” explanation (i.e. the “hard problem”), but this implicit reason requires you to not treat IIT in a vacuum.


  • It is only continuous because it is random, so prior to making a measurement, you describe it in terms of a probability distribution called the state vector. The bits 0 and 1 are discrete, but if I said it was random and asked you to describe it, you would assign it a probability between 0 and 1, and thus it suddenly becomes continuous. (Although, in quantum mechanics, probability amplitudes are complex-valued.) The continuous nature of it is really something epistemic and not ontological. We only observe qubits as either 0 or 1, with discrete values, never anything in between the two.


  • The only observer of the mind would be an outside observer looking at you. You yourself are not an observer of your own mind nor could you ever be. I think it was Feuerbach who originally made the analogy that if your eyeballs evolved to look inwardly at themselves, then they could not look outwardly at the outside world. We cannot observe our own brains as they only exist to build models of reality, if our brains had a model of itself it would have no room left over to model the outside world.

    We can only assign an object to be what is “sensing” our thoughts through reflection. Reflection is ultimately still building models of the outside world but the outside world contains a piece of ourselves in a reflection, and this allows us to have some limited sense of what we are. If we lived in a universe where we somehow could never leave an impression upon the world, if we could not see our own hands or see our own faces in the reflection upon a still lake, we would never assign an entity to ourselves at all.

    We assign an entity onto ourselves for the specific purpose of distinguishing ourselves as an object from other objects, but this is not an a priori notion (“I think therefore I am” is lazy sophistry). It is an a posteriori notion derived through reflection upon what we observe. We never actually observe ourselves as such a thing is impossible. At best we can over reflections of ourselves and derive some limited model of what “we” are, but there will always be a gap between what we really are and the reflection of what we are.

    Precisely what is “sensing your thoughts” is yourself derived through reflection which inherently derives from observation of the natural world. Without reflection, it is meaningless to even ask the question as to what is “behind” it. If we could not reflect, we would have no reason to assign anything there at all. If we do include reflection, then the answer to what is there is trivially obvious: what you see in a mirror.




  • Why are you isolating a single algorithm? There are tons of them that speed up various aspects of linear algebra and not just that single one, and many improvements to these algorithms since they were first introduced, there are a lot more in the literature than just in the popular consciousness.

    The point is not that it will speed up every major calculation, but these are calculations that could be made use of, and there will likely even be more similar algorithms discovered if quantum computers are more commonplace. There is a whole branch of research called quantum machine learning that is centered solely around figuring out how to make use of these algorithms to provide performance benefits for machine learning algorithms.

    If they would offer speed benefits, then why wouldn’t you want to have the chip that offers the speed benefits in your phone? Of course, in practical terms, we likely will not have this due to the difficulty and expense of quantum chips, and the fact they currently have to be cooled below to near zero degrees Kelvin. But your argument suggests that if somehow consumers could have access to technology in their phone that would offer performance benefits to their software that they wouldn’t want it.

    That just makes no sense to me. The issue is not that quantum computers could not offer performance benefits in theory. The issue is more about whether or not the theory can be implemented in practical engineering terms, as well as a cost-to-performance ratio. The engineering would have to be good enough to both bring the price down and make the performance benefits high enough to make it worth it.

    It is the same with GPUs. A GPU can only speed up certain problems, and it would thus be even more inefficient to try and force every calculation through the GPU. You have libraries that only call the GPU when it is needed for certain calculations. This ends up offering major performance benefits and if the price of the GPU is low enough and the performance benefits high enough to match what the consumers want, they will buy it. We also have separate AI chips now as well which are making their way into some phones. While there’s no reason at the current moment to believe we will see quantum technology shrunk small and cheap enough to show up in consumer phones, if hypothetically that was the case, I don’t see why consumers wouldn’t want it.

    I am sure clever software developers would figure out how to make use of them if they were available like that. They likely will not be available like that any time in the near future, if ever, but assuming they are, there would probably be a lot of interesting use cases for them that have not even been thought of yet. They will likely remain something largely used by businesses but in my view it will be mostly because of practical concerns. The benefits of them won’t outweigh the cost anytime soon.


  • Uh… one of those algorithms in your list is literally for speeding up linear algebra. Do you think just because it sounds technical it’s “businessy”? All modern technology is technical, that’s what technology is. It would be like someone saying, “GPUs would be useless to regular people because all they mainly do is speed up matrix multiplication. Who cares about that except for businesses?” Many of these algorithms here offer potential speedup for linear algebra operations. That is the basis of both graphics and AI. One of those algorithms is even for machine learning in that list. There are various algorithms for potentially speeding up matrix multiplication in the linear. It’s huge for regular consumers… assuming the technology could ever progress to come to regular consumers.


  • bunchberry@lemmy.worldtoScience Memes@mander.xyzCrystals
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    19 days ago

    OrchOR makes way too many wild claims for there to easily be any evidence for it. Even if we discover quantum effects (in the sense of scalable interference effects which have absolutely not been demonstrated) in the brain that would just demonstrate there are quantum effects in the brain, OrchOR is filled with a lot of assumptions which go far beyond this and would not be anywhere near justified. One of them being its reliance on gravity-induced collapse, which is nonrelativistic, meaning it cannot reproduce the predictions of quantum field theory, our best theory of the natural world.

    A theory is ultimately not just a list of facts but a collection of facts under a single philosophical interpretation of how they relate to one another. This is more of a philosophical issue, but even if OrchOR proves there is gravitational induced collapse and that there is quantum effects in the brain, we would still just take these two facts separately. OrchOR tries to unify them under some bizarre philosophical interpretation called the Penrose–Lucas argument that says because humans can believe things that are not proven, therefore human consciousness must be noncomputable, and because human consciousness is not computable, it must be reducible to something that you cannot algorithmically predict its outcome, which would be true of an objective collapse model. Ergo, wave function collapse causes consciousness.

    Again, even if they proved that there is scalable quantum interference effects in the brain, even if they proved that there is gravitationally induced collapse, that alone does not demonstrate OrchOR unless you actually think the Penrose-Lucas argument makes sense. They would just be two facts which we would take separately as fact. It would just be a fact that there is gravitionally induced collapse, a fact that there is scalable quantum interference effects in the brain but there would be no reason to adopt any of their claims about “consciousness.”

    But even then, there is still no strong evidence that the brain in any way makes use of quantum interference effects, only loose hints that it may or not be possible with microtubules, and there is definitely no evidence of the gravitationally induced collapse.


  • A person who would state they fully understand quantum mechanics is the last person i would trust to have any understanding of it.

    I find this sentiment can lead to devolving into quantum woo and mysticism. If you think anyone trying to tell you quantum mechanics can be made sense of rationally must be wrong, then you implicitly are suggesting that quantum mechanics is something that cannot be made sense of, and thus it logically follows that people who are speaking in a way that does not make sense and have no expertise in the subject so they do not even claim to make sense are the more reliable sources.

    It’s really a sentiment I am not a fan of. When we encounter difficult problems that seem mysterious to us, we should treat the mystery as an opportunity to learn. It is very enjoyable, in my view, to read all the different views people put forward to try and make sense of quantum mechanics, to understand it, and then to contemplate on what they have to offer. To me, the joy of a mystery is not to revel in the mystery, but to search for solutions for it, and I will say the academic literature is filled with pretty good accounts of QM these days. It’s been around for a century, a lot of ideas are very developed.

    I also would not take the game Outer Wilds that seriously. It plays into the myth that quantum effects depend upon whether or not you are “looking,” which is simply not the case and largely a myth. You end up with very bizarre and misleading results from this, for example, in the part where you land on the quantum moon and have to look at the picture of it for it to not disappear because your vision is obscured by fog. This makes no sense in light of real physics because the fog is still part of the moon and your ship is still interacting with the fog, so there is no reason it should hop to somewhere else.

    Now quantum science isn’t exactly philosophy, ive always been interested in philosophy but its by studying quantum mechanics, inspired by that game that i learned about the mechanic of emerging properties. I think on a video about the dual slit experiment.

    The double-slit experiment is a great example of something often misunderstood as somehow evidence observation plays some fundamental role in quantum mechanics. Yes, if you observe the path the two particles take through the slits, the interference pattern disappears. Yet, you can also trivially prove in a few line of calculation that if the particle interacts with a single other particle when it passes through the two slits then it would also lead to a destruction of the interference effects.

    You model this by computing what is called a density matrix for both the particle going through the two slits and the particle it interacts with, and then you do what is called a partial trace whereby you “trace out” the particle it interacts with giving you a reduced density matrix of only the particle that passes through the two slits, and you find as a result of interacting with another particle its coherence terms would reduce to zero, i.e. it would decohere and thus lose the ability to interfere with itself.

    If a single particle interaction can do this, then it is not surprising it interacting with a whole measuring device can do this. It has nothing to do with humans looking at it.

    At that point i did not yet know that emergence was already a known topic in philosophy just quantum science, because i still tried to avoid external influences but it really was the breakthrough I needed and i have gained many new insights from this knowledge since.

    Eh, you should be reading books and papers in the literature if you are serious about this topic. I agree that a lot of philosophy out there is bad so sometimes external influences can be negative, but the solution to that shouldn’t be to entirely avoid reading anything at all, but to dig through the trash to find the hidden gems.

    My views when it comes to philosophy are pretty fringe as most academics believe the human brain can transcend reality and I reject this notion, and I find most philosophy falls right into place if you reject this notion. However, because my views are a bit fringe, I do find most philosophical literature out there unhelpful, but I don’t entirely not engage with it. I have found plenty of philosophers and physicists who have significantly helped develop my views, such as Jocelyn Benoist, Carlo Rovelli, Francois-Igor Pris, and Alexander Bogdanov.


  • I wouldn’t take Chalmers’ opinions on things that seriously. Chalmers is a metaphysical realist, a very dubious philosophical position, and thus all his positions are inherently circular.

    Metaphysical realism presumes dualism from the get-go, that there is some fundamental gap between an unobservable “objective” reality beyond everything we can ever hope to perceive, and then everything we do perceive is some not real and a unique property associated with mammalian brains. To be not real suggests it is outside of reality, that it somehow transcends reality.

    This was what Thomas Nagel argued in his famous paper “What is it like to be a Bat?” and then Chalmers merely cites this as the basis for saying the brain has a property that transcends reality, and then concludes if explaining the function of the brain (what he calls the “easy problem”) is not enough to explain this transcendence, how is it that an entirely invisible reality gives rise to the reality we observe.

    But the entire thing is circular, as there’s no convincing justification the brain transcends reality in the first place, and you only run into this “hard problem” if you presume such a transcendence takes place. Bizarrely, idealists and dualists love to demand that people who are not convinced that this transcendental “consciousness” even exists have to solve the “hard problem” or idealism and dualism are proven. But it’s literally the opposite: idealism and dualism (as well as metaphysical materialism) are entirely untenable positions until they solve the philosophical problem their position creates.

    I am especially not going to be convinced that this transcendental consciousness even exists if, as Chalmers has shown, it leads to “hard” philosophical paradoxes. Metaphysical realists for some reason don’t see their philosophy leading to a massive paradox as a reason for questioning its foundations, but then turn around and insist reality itself must be inherently paradoxical, that there really is a fundamental gap between mind and body. Chalmers himself is a self-described dualist.

    It’s from this basis that Chalmers says you cannot prove whether or not something is conscious, because for him consciousness is something transcendental that we can’t concretely tie back to anything demonstrably real. It has no tangible definition, there are no set of obervables associated with it. If you have one transcendentally conscious person next to another non-transcendentally conscious person, Chalmers would say that there is simply no conceivable observation you could ever make to distinguish between the two.

    Yet, if there are no conceivable ways to distinguish the two, then this transcendental property of “consciousness” is just not conceivable at all. It’s a word without concrete meaning, a floating abstraction, and should not be taken particularly seriously. At least, not until Chalmers solves the hard problem of consciousness and proves his metaphysical realist worldview can be made internally consistent, only then will I take his philosophy as even worthy of consideration.


  • This is why many philosophers came to criticize metaphysical logic in the 1800s, viewing it as dealing with absolutes when reality does not actually exist in absolutes, stating that we need some other logical system which could deal with the “fuzziness” of reality more accurately. That was the origin of the notion of dialectical logic from philosophers like Hegel and Engels, which caught on with some popularity in the east but then was mostly forgotten in the west outside of some fringe sections of academia. Even long prior to Bell’s theorem, the physicist Dmitry Blokhintsev, who adhered to this dialectical materialist mode of thought, wrote a whole book on quantum mechanics where the first part he discusses the need to abandon the false illusion of the rigidity and concreteness of reality and shows how this is an illusion even in the classical sciences where everything has uncertainty, all predictions eventually break down, nothing is never possible to actually fully separate something from its environment. These kinds of views heavily influenced the contemporary physicist Carlo Rovelli as well.


  • And as any modern physicist will tell you: most of reality is indeed invisible to us. Most of the universe is seemingly comprised of an unknown substance, and filled with an unknown energy.

    How can we possibly know this unless it was made through an observation?

    Most of the universe that we can see more directly follows rules that are unintuitive and uses processes we can’t see. Not only can’t we see them, our own physics tells is it is literally impossible to measure all of them consistently.

    That’s a hidden variable theory, presuming that systems really have all these values and we just can’t measure them all consistently due to some sort of practical limitation but still believing that they’re there. Hidden variable theories aren’t compatible with the known laws of physics. The values of the observables which become indefinite simply cease to have existence at all, not that they are there but we can’t observe them.

    But subjective consciousness and qualia fit nowhere in our modern model of physics.

    How so? What is “consciousness”? Why do you think objects of qualia are special over any other kind of object?

    I don’t think it’s impossible to explain consciousness.

    You haven’t even established what it is you’re trying to explain or why you think there is some difficulty to explain it.

    We don’t even fully understand what the question is really asking. It sidesteps our current model of physics.

    So, you don’t even know what you’re asking but you’re sure that it’s not compatible with the currently known laws of physics?

    I don’t subscribe to Nagel’s belief that it is impossible to solve, but I do understand how the points he raises are legitimate points that illustrate how consciousness does not fit into our current scientific model of the universe.

    But how?! You are just repeating the claim over and over again when the point of my comment is that the claim itself is not justified. You have not established why there is a “hard problem” at all but just continually repeat that there is.

    If I had to choose anyone I’d say my thoughts on the subject are closest to Roger Penrose’s line of thinking, with a dash of David Chalmers.

    Meaningless.

    I think if anyone doesn’t see why consciousness is “hard” then there are two possibilities: 1) they haven’t understood the question and its scientific ramifications 2) they’re not conscious.

    You literally do not understand the topic at hand based on your own words. Not only can you not actually explain why you think there is a “hard problem” at all, but you said yourself you don’t even know what question you’re asking with this problem. Turning around and then claiming everyone who doesn’t agree with you is just some ignoramus who doesn’t understand then is comically ridiculous, and also further implying people who don’t agree with you may not even be conscious.

    Seriously, that’s just f’d up. What the hell is wrong with you? Maybe you are so convinced of this bizarre notion you can’t even explain yourself because you dehumanize everyone who disagrees with you and never take into consideration other ideas.


  • This is accurate, yes. The cat in the box is conscious presumably, in my opinion of cats at least, but still can be “not an observer” from the POV of the scientist observing the experiment from outside the box.

    “Consciousness” is not relevant here at all. You can write down the wave function of a system relative to a rock if you wanted, in a comparable way as writing down the velocity of a train from the “point of view” of a rock. It is coordinate. It has nothing to do with “consciousness.” The cat would perceive a definite state of the system from its reference frame, but the person outside the box would not until they interact with it.

    QM is about quite a lot more than coordinate systems

    Obviously QM is not just coordinate systems. The coordinate nature of quantum mechanics, the relative nature of it, is merely a property of the theory and not the whole theory. But the rest of the theory does not have any relevance to “consciousness.”

    and in my opinion will make it look weird in retrospect once physics expands to a more coherent whole

    The theory is fully coherent and internally consistent. It amazes me how many people choose to deny QM and always want to rush to change it. Your philosophy should be guided by the physical sciences, not the other way around. People see QM going against their basic intuitions and their first thought is it must be incomplete and needs to have additional complexity added to it to make it fit their intuitions, rather than just questioning that maybe their basic intuitions are wrong.

    Your other comment was to a Wikipedia page which if you clicked the link on your own source it would’ve told you that the scientific consensus on that topic is that what you’re presenting is a misinterpretation.

    A simple search on YouTube could’ve also brought up several videos explaining this to you.

    Edit: Placing my response here as an edit since I don’t care to continue this conversation so I don’t want to notify.

    Yes, that was what I said. Er, well… QM, as I understand it, doesn’t have to do anything with shifting coordinate systems per se (and in fact is still incompatible with relativity). They’re just sort of similar in that they both have to define some point of view and make everything else in the model relative to it. I’m still not sure why you brought coordinate systems into it.

    A point of view is just a colloquial term to refer to a coordinate system. They are not coordinate in the exact same way but they are both coordinate.

    My point was that communication of state to the observer in the system, or not, causes a difference in the outcome. And that from the general intuitions that drive almost all of the rest of physics, that’s weird and sort of should be impossible.

    No, it doesn’t not, and you’re never demonstrated that.

    Sure. How is it when combined with macro-scale intuition about the way natural laws work, or with general relativity?

    We have never observed quantum effects on the scale where gravitational effects would also be observable, so such a theory, if we proposed one, would not be based on empirical evidence.

    This is very, very very much not what I am doing. What did I say that gave you the impression I was adding anything to it?

    You literally said in your own words we need to take additional things into account we currently are not. You’re now just doing a 180 and pretending you did not say what literally anyone can scroll up and see that you said.

    I am not talking about anything about retrocausality here, except maybe accidentally.

    Then you don’t understand the experiment since the only reason it is considered interesting is because if you interpret it in certain ways it seems to imply retrocausality. Literally no one has ever treated it as anything more than that. You are just making up your own wild implications from the experiment.

    I was emphasizing the second paragraph; “wave behavior can be restored by erasing or otherwise making permanently unavailable the ‘which path’ information.”

    The behavior of the system physically changes when it undergoes a physical interaction. How surprising!


  • bunchberry@lemmy.worldtoScience Memes@mander.xyzdouble slit
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    1 month ago

    Both these figures are embarrassingly bad.

    Hoffman confuses function for perception and constantly uses arguments demonstrating things can interpret reality incorrectly (which is purely a question of function) in order to argue they cannot perceive reality “as it is.,” which is a huge non-sequitur. He keeps going around promoting his “theorem” which supposedly “proves” this yet if you read his book where he explains his theorem it is again clearly about function as his theorem only shows that limitations in cognitive and sensory capabilities can lead something to interpret reality incorrectly yet he draws a wild conclusion which he never justifies that this means they do not perceive reality “as it is” at all.

    Kastrup is also just incredibly boring because he never reads books so he is convinced the only two philosophical schools in the universe are his personal idealism and metaphysical realism, which the latter he constantly incorrectly calls “materialism” when not all materialist schools of thought are even metaphysically realist. Unless you are yourself a metaphysical realist, nothing Kastrup has ever written is interesting at all, because he just pretends you don’t exist.

    Metaphysical realism is just a popular worldview in the west that most Laymen tend to naturally take on unwittingly. If you’re a person who has ever read books in your life, then you’d quickly notice that attacking metaphysical realism doesn’t get you to idealism, at best it gets you to metaphysical realism being not a coherent worldview… which that is the only thing I agree with Kastrup with.



  • Kastrup is entirely unconvincing because he pretends the only two schools of philosophy in the whole universe are his specific idealism and metaphysical realism which he falsely calls the latter “materialism.” He thus never feels the need to ever address anything outside of a critique of a single Laymen understanding of materialism which is more popular in western countries than eastern countries, ignoring the actual wealth of philosophical literature.

    Anyone who actually reads books on philosophy would inevitably find Kastrup to be incredibly unconvincing as he, by focusing primarily on a single school, never justifies many of his premises. He begins from the very beginning talking about “conscious experience” and whatnot when, if you’re not a metaphysical realist, that is what you are supposed to be arguing in the first place. Unless you’re already a dualist or metaphysical realist, if you are pretty much any other philosophical school like contextual realist, dialectical materialist, empiriomonist, etc, you probably already view reality as inherently observable, and thus perception is just reality from a particular point-of-view. It then becomes invalid to add qualifiers to it like “conscious experience” or “subjective experience” as reality itself cannot had qualifiers.

    I mean, the whole notion of “subjective experience” goes back to Nagel who was a metaphysical realist through-and-through and wrote a whole paper defending that notion, “What is it like to be a Bat?”, and this is what Kastrup assumes his audience already agrees with from the get-go. He never addresses any of the criticisms of metaphysical realism but pretends like they don’t exist and he is the unique sole critic of it and constantly calls metaphysical realism “materialism” as if they’re the same philosophy at all. He then builds all of his arguments off of this premise.


  • Classical computers compute using 0s and 1s which refer to something physical like voltage levels of 0v or 3.3v respectively. Quantum computers also compute using 0s and 1s that also refers to something physical, like the spin of an electron which can only be up or down. Although these qubits differ because with a classical bit, there is just one thing to “look at” (called “observables”) if you want to know its value. If I want to know the voltage level is 0 or 1 I can just take out my multimeter and check. There is just one single observable.

    With a qubit, there are actually three observables: σx, σy, and σz. You can think of a qubit like a sphere where you can measure it along its x, y, or z axis. These often correspond in real life to real rotations, for example, you can measure electron spin using something called Stern-Gerlach apparatus and you can measure a different axis by physically rotating the whole apparatus.

    How can a single 0 or 1 be associated with three different observables? Well, the qubit can only have a single 0 or 1 at a time, so, let’s say, you measure its value on the z-axis, so you measure σz, and you get 0 or 1, then the qubit ceases to have values for σx or σy. They just don’t exist anymore. If you then go measure, let’s say, σx, then you will get something entirely random, and then the value for σz will cease to exist. So it can only hold one bit of information at a time, but measuring it on a different axis will “interfere” with that information.

    It’s thus not possible to actually know the values for all the different observables because only one exists at a time, but you can also use them in logic gates where one depends on an axis with no value. For example, if you measure a qubit on the σz axis, you can then pass it through a logic gate where it will flip a second qubit or not flip it because on whether or not σx is 0 or 1. Of course, if you measured σz, then σx has no value, so you can’t say whether or not it will flip the other qubit, but you can say that they would be correlated with one another (if σx is 0 then it will not flip it, if it is 1 then it will, and thus they are related to one another). This is basically what entanglement is.

    Because you cannot know the outcome when you have certain interactions like this, you can only model the system probabilistically based on the information you do know, and because measuring qubits on one axis erases its value on all others, then some information you know about the system can interfere with (cancel out) other information you know about it. Waves also can interfere with each other, and so oddly enough, it turns out you can model how your predictions of the system evolve over the computation using a wave function which then can be used to derive a probability distribution of the results.

    What is even more interesting is that if you have a system like this where you have to model it using a wave function, it turns out it can in principle execute certain algorithms exponentially faster than classical computers. So they are definitely nowhere near the same as classical computers. Their complexity scales up exponentially when trying to simulate quantum computers on a classical computer. Every additional qubit doubles the complexity, and thus it becomes really difficult to even simulate small numbers of qubits. I built my own simulator in C and it uses 45 gigabytes of RAM to simulate just 16. I think the world record is literally only like 56.



  • Even if you believe there really exists a “hard problem of consciousness,” even Chalmers admits such a thing would have to be fundamentally unobservable and indistinguishable from something that does not have it (see his p-zombie argument), so it could never be something discovered by the sciences, or something discovered at all. Believing there is something immaterial about consciousness inherently requires an a priori assumption and cannot be something derived from a posteriori observational evidence.