Scott Aaronson On The Relevance Of Quantum Mechanics To Brain Preservation, Uploading, And Identity.
Biography: Scott Aaronson is an Associate Professor of Electrical Engineering and Computer Science at MIT. His research interests center around the capabilities and limits of quantum computers, and computational complexity theory more generally. He also has written about consciousness and personal identity and the relevance of quantum mechanics to these issues.
Michael Cerullo: Thanks for taking the time to talk with me. Given the recent advances in brain preservation, questions of personal identity are moving from merely academic to extremely practical questions. I want to focus on your ideas related to the relevance of quantum mechanics to consciousness and personal identity which are found in your paper “Ghost in the Quantum Turing Machine” (http://arxiv.org/abs/1306.0159), your blog “Could a Quantum Computer Have Subjective Experience?” (http://www.scottaaronson.com/blog/?p=1951), and your book “Quantum Computing since Democritus” (http://www.scottaaronson.com/democritus/).
Before we get to your own speculations in this field I want to review some of the prior work of Roger Penrose and Stuart Hameroff (http://www.quantumconsciousness.org/content/hameroff-penrose-review-orch-or-theory). Let me try to summarize some of the criticism of their work (including some of your own critiques of their theory). Penrose and Hameroff abandon conventional wisdom in neuroscience (i.e. that neurons are the essential computational element in the brain) and instead posit that the microtubules (which conventional neuroscience tell us are involved in nucleic and cell division, organization of intracellular structure, and intracellular transport, as well as ciliary and flagellar motility) are an essential part of the computational structure of the brain. Specifically, they claim the microtubules are quantum computers that grant a person the ability to perform non-computable computations (and Penrose claims these kinds of computations are necessary for things like mathematical understanding). The main critiques of their theory are: it relies on future results in quantum gravity that don’t exist; there is no empirical evidence that microtubules are relevant to the function of the brain; work in quantum decoherence also makes it extremely unlikely that the brain is a quatum computer; even if a brain could somehow compute non-computable functions it isn’t clear what this has to do with consciousness. Would you say these are fair criticisms of their theory and are there any other criticisms you see as relevant?
Scott Aaronson: Yes, I think all four of those are fair criticisms! I could add a fifth criticism: Penrose’s case for the brain having non-computational abilities relies on an appeal to Gödel’s Incompleteness Theorem, to the idea that no machine working within a fixed formal system can prove the system’s consistency, whereas a human can “just see” that it’s consistent. But like most mathematicians and computer scientists, I don’t agree with that argument, because I think a machine could show all the same external behavior as a human who “sees” a formal system’s consistency. So then, the argument devolves into one about indescribable inner experiences, of “just seeing” (for example) that set theory is consistent. But if we wanted to rest the case on indescribable inner experiences, then why not forget about Gödel’s Theorem, and just talk about less abstruse things like the experience of falling in love or tasting strawberries or whatever?
Michael Cerullo: Your own work in this field attempts to show the relevance of quantum mechanics to consciousness without requiring us to abandon what we know from neuroscience. You also state that the motivation for some of your speculations is to avoid the seeming paradoxes (e.g. Boltzmann’s brains, copies, degrees of identity, multiple copies etc.) that would occur if personal identity could be copied as easy as any other type of information. Can you expand on this?
Scott Aaronson: To my mind, one of the central things that any account of consciousness needs to do, is to explain where your consciousness “is” in space, which physical objects are the locus of it. I mean, not just in ordinary life (where presumably we can all agree that your consciousness resides in your brain, and especially in your cerebral cortex—though which parts of your cerebral cortex?), but in all sorts of hypothetical situations that we can devise. What if we made a backup copy of all the information in your brain and ran it on a server somewhere? Knowing that, should you then expect there’s a 50% chance that “you’re” the backup copy? Or are you and your backup copy somehow tethered together as a single consciousness, no matter how far apart in space you might be? Or are you tethered together for a while, but then become untethered when your experiences start to diverge? Does it matter if your backup copy is actually “run,” and what counts as running it? Would a simulation on pen and paper (a huge amount of pen and paper, but no matter) suffice? What if the simulation of you was encrypted, and the only decryption key was stored in some other galaxy? Or, if the universe is infinite, should you assume that “your” consciousness is spread across infinitely many physical entities, namely all the brains physically indistinguishable from yours—including “Boltzmann brains” that arise purely by chance fluctuations?
It’s very easy to get disoriented, to feel a sense of vertigo, thinking about all these science-fiction puzzles. But before we tie ourselves in knots, perhaps one response is to step back and think hard about which of these scenarios are actually possible, according to the laws of physics as we currently understand them. For example, could you actually copy all the functionally-relevant information in a human brain, convert it to digital form, without an invasive scan that would kill the brain in the process? Well, the answer to that question hinges on how much information about a brain you think is “functionally relevant.” If you believe the brain has a “clean digital abstraction layer” containing all the information relevant to consciousness—say, the neurons, their wiring diagram, the approximate synapse strengths, a few other things—and that that layer “notices” the underlying molecular layer at most as a thermal noise source, then presumably the answer is yes, a sufficiently advanced civilization could upload your consciousness to a computer and thereafter make as many copies of it as it wanted. If, on the other hand, you believe that microscopic details of your brain—e.g., the exact quantum state of some sodium-ion channel, which might later get amplified to macroscopic scale and influence whether a neuron fires, etc.—are an important part of your personal identity, then the rules of quantum mechanics would generally rule out making a sufficiently precise copy of those details, so that some of these science-fiction scenarios couldn’t even get off the ground. So, I don’t have answers, but those are the sorts of questions that I’ve tried to draw attention to, because I think progress on them might actually be possible.
Michael Cerullo: Before I get into your thoughts on freebits and the arrow of time, I want to discuss the relevance of the quantum no-cloning theorem to identity. To remind our readers, the no-cloning theorem states that it is impossible to make an exact copy of any quantum state . In quantum computing the relevance of the no-cloning theorem is obvious: error correction based on copying quantum qubits is impossible. Now let’s jump to the macroscopic scale. Information is copied with high fidelity all the time at the nanoscale level: nature does this every time DNA is copied during cell division and we do this whenever we copy files on a computer or burn pits onto a blue ray disk. The information in these systems can be completely described at the classical level, and of course this brings up the issues of the quantum measurement problem and how the classical world develops from the quantum world (which no one really understands). Neuroscience seems to tell us that identity (i.e. memory and personality) is encoded in the connections and strength of neural synapses which can be completely modeled with classical physics. Given this it would seem personal identity can be wholly described within classical physics and is more like the information in a blue-ray than a qubit, and thus the no-cloning isn’t relevant at this scale. Can you tell me why you disagree and how the no-cloning may be relevant to the brain, consciousness, or identity?
Scott Aaronson: As I said, I don’t know. On the one hand, I find Penrose and Hameroff’s speculations about quantum gravity effects in microtubules to be totally implausible. But on the other hand, even the most hardheaded neuroscientist is going to model action potentials in neurons using the Hodgkin-Huxley equations, which treat neural firings as partly stochastic events—i.e., events that are influenced by molecular details that are treated as outside neuroscience’s scope. And it’s not even particularly controversial to say that this creates a causal path for quantum indeterminism to get chaotically amplified, and eventually influence (say) the course of a human decision. The question, of course, is whether any of that matters. In my way of thinking, the question becomes: could an external observer, using far-future technology, decompose everything in your brain into (a) a “digital, classical layer” that can be scanned and copied, and (b) a “thermal noise layer” that can’t be copied, but that can safely be ignored with no effect on your personal identity? So, I dunno: is it obvious to you that the answer is yes?
Michael Cerullo: Now I want to discuss some of your thoughts about complexity, the arrow of time and freebits and their relation to identity. Rather than try to summarize your arguments for freebits and the arrow of time, I will refer our readers to your very readable paper “The Ghost in the Quantum Turing Machine” and one of your blogs where you discuss these issues (http://www.scottaaronson.com/blog/?p=1951). One of the limitations with computationalism is that no one quite understands what exactly it means to implement a computation. Many people agree there is something wrong with saying that a look up table that could pass a Turing test is conscious, even if this look up table is implemented in the real world. I share this intuition and you also mention your doubts about this possibility. In your book “Quantum Computing since Democritus” you discuss this question and how it may be related to questions of computational complexity. To implement the Turing test look up table would be a problem with NP complexity. Hence having a look up table that could pass a Turing test doesn’t really you help you make a program that can pass the Turing test in the real world. I can’t help but be reminded of the Borges’ Library of Babel here. Having the Library of Babel doesn’t really give you any information since it would be easier to create it than search for it. Is this a fair summary of your current views? Any thoughts on how complexity and the arrow of time may be related to the question of implementing a computation?
Scott Aaronson: Well, the lookup table is sort of the extreme version of some of the thought experiments that we discussed earlier. If anything that passes a Turing Test is conscious, then what about a huge table that just stores your replies in every five-minute conversation I could possibly have with you? Would it even matter if anyone consulted the table, or could it just sit there, silently bringing about your consciousness? (And for that matter, why does the lookup table even need to be physically built? Why isn’t its abstract existence, as a function mapping inputs to outputs, enough to bring about your consciousness? That’s a slippery slope that Max Tegmark, for example, with his “Mathematical Universe Hypothesis,” is happy to ride all the way to the bottom!)
Now, some people point out that such a lookup table would require size that grows exponentially in the length of the conversation—so in particular, it would very quickly exceed the storage capacity of the observable universe. And some of them might go even further, and conjecture that any simulation of you that didn’t suffer such an exponential explosion would need to have memories, internal representations of concepts, etc. that might of course differ in detail from the way your brain organizes things, but would still be “vaguely brain-like”—and that would therefore, in their view, bring about consciousness for the same organizational reasons why your brain brings about consciousness (reasons that wouldn’t apply to the lookup table).
I still haven’t figured out what I think about that position, but I do find it fascinating—not only because of how it brings one of my favorite subjects (polynomial versus exponential complexity) into the discussion of consciousness, but also because of how it answers a philosophical thought experiment (would the giant lookup table be conscious, or not?) by questioning the experiment’s premises, by asking whether the lookup table, or anything like it, could exist in our universe. In that respect, it’s analogous to what I tried to do in my “Ghost in the Quantum Turing Machine” essay: namely, to take crazy philosophical thought experiments (in my case, involving perfect copies of you), but then ask different questions about them than the ones you’re “supposed” to ask—questions about whether our best current theories of physics, cosmology, computer science, and so forth predict the experiments can be done or not.
Michael Cerullo: How about freebits? Do you think they have any relationship to implementing a computation?
Scott Aaronson: “Freebits” are just a label for whatever it is that you believe in, if you think the answer to my earlier question about copyability is “no”: that is, if you think that, even with arbitrarily advanced technology, it won’t be possible to scan your brain accurately enough to make copies that are probabilistically indistinguishable from the original. Freebits are bits about the physical state of your brain (and ultimately, about your behavior) that the copying procedure would necessarily miss.
To make myself clear: unlike in Penrose and Hameroff’s model, freebits are not “oracles” that let you solve uncomputable problems, or do anything else that defies a conventional physical understanding of the brain. So for example, even if I didn’t know any of the freebits relevant to you, I see no reason at all why I couldn’t build a second brain that was extremely similar to yours, that not only passed the Turing Test but fooled a lot of people into thinking it was you, that behaved similarly to you in most situations. But by hypothesis, the copy wouldn’t behave like you in all situations, and the differences could serve as a sort of empirical certificate that your consciousness hadn’t been cleaved into two, or transferred from one physical substrate to another, or anything like that. A second consciousness might or might not have been brought into being. But at any rate, the “original” you would be inextricably bound up with microscopic, unclonable details of your brain state that aren’t magical, don’t give you any computational superpowers or anything like that, but are part of how we localize which physical entity we’re talking about when we talk about “you.”
Michael Cerullo: In your paper “The Ghost in the Quantum Turing Machine” you discuss how freebits may help to solve the problem of free will by preventing any perfect prediction of human behavior. In this paper you seem to be suggesting that free will is necessary for consciousness and therefore for any conception of personal identity. Can you expand on this?
Scott Aaronson: Look, I have no idea whether free will in the sense that interests me (that is, the sense of in-principle unpredictability) is necessary for consciousness. The one thing I’m confident about is that, if it’s not necessary, then any account of consciousness will have to solve all sorts of thorny conceptual problems that it could otherwise avoid. For in that case, one and the same intelligent being—that is, a being that responds to all possible stimuli in the same way—could be copied promiscuously all over the universe and transferred to countless physical substrates: not only to digital electronics but to pen-and-paper, even giant lookup tables, etc. And we’d then have to confront questions about which of those copies “is you,” what you should do if someone asks you to place a bet about “which one you are,” and so on. Any algorithm that took as input a description of the entire universe, and tried to locate the “you” parts of it, would then have to be much more complicated!
Michael Cerullo: In neurology, there are examples of syndromes where people seem to believe they have no free will or that they have control over actions that they clearly do not. Doesn’t this suggest that free will is simply one more qualia, the qualia of feeling like we (whatever “we” is, if you take something like Baars’ Theater of Consciousness approach for example, it doesn’t have to involve a homunculus) have control of our actions?
Scott Aaronson: To my way of thinking, free will is special because it’s bound up with the predictability of your actions—and in particular, with the question of whether it’s possible to create a second entity that behaves indistinguishably from you, and which an empiricist like me would therefore have to say is you, is a second copy or instantiation of you that inhabits the same world. I like that framing precisely because it’s not about your subjective feeling of freedom or lack of freedom: rather, we’re asking an actual, bona fide question about the physical universe that could turn out one way or the other.
You know, when I wrote an 85-page essay about these issues, I tried as hard as I could not once to rely on introspection or “what it feels like” to make a choice, because that strikes me as just an obvious nonstarter. I mean, introspection can’t even tell us vastly simpler, more uncontroversial things about how our minds work, like how our visual systems pick out triangles and squares, stuff like that. And given all the moral, philosophical, and theological issues with which free will is entangled, it seems obvious that people could “feel like” they had free will (or say that they felt that way, or convince themselves they did) even if they didn’t, and vice versa.
By contrast, I want a notion of “free will” that’s clear and well-defined enough that someday, in principle, we could tell people that they had no free will even if they felt sure they had it, or conversely, tell them they had it even if they felt sure they didn’t. And focusing on the in-principle predictability of our actions seems to me like a huge step in that direction.
Michael Cerullo: Thanks for taking time to talk with me, I look forward to reading more of your work on these issues.
Nobelist echoes work on vision, color, symmetry, quantum theory and higher dimension: http://bit.ly/1PJvneX
In a way consciousness related to the brain or other bio-medical mechanical devices can be real in not so difficult to understand ways. For instance if the brain was like a windmill, consciousness would be the brain as the propeller. But the potential for propulsion in resemblance and continuance after the windmill had given it height and reach/exposure to the wind/sans does not depend solely upon the windmill and propeller setup and not even the wind.
The brain gives birth to consciousness (as U.C.L.A. neuroscience professors have noted). I would add: a calf born breech does not need the birth cow to moo and give milk, only to be born and give birth to the phenomenon of consciousness.
Hi everyone
Hi everyone
I’m responding to criticism of our work in this exchange,
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Michael Cerullo (MC)
Penrose and Hameroff abandon conventional wisdom in neuroscience (i.e. that neurons are the essential computational element in the brain)…
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Stuart Hameroff (SH)
We don’t abandon conventional wisdom in terms of neurons. We abandon conventional stupidity which ignores neuronal interiors in favor of skin-deep views of inanimate neuronal bit-like function (like viewing all of medicine through dermatology, or the brain through phrenology). Conventional ‘wisdom’ is an insult to neurons, especially when one considers complex cognitive capacities of single cell organisms. For example paramecium can swim, find food and mates, learn, and have sex, without any synaptic connections, using their microtubules. AI/brain mappers and preservationists should simulate a paramecium before worrying about a brain, even that of a worm.
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MC …and instead posit that the microtubules (which conventional neuroscience tell us are involved in nucleic and cell division, organization of intracellular structure, and intracellular transport, as well as ciliary and flagellar motility) are an essential part of the computational structure of the brain.
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SH Not really ‘instead’ of, but in addition to…But true, we do posit that. Specifically we posit that brain computational structure and dynamics are hierarchical, and fractal-like, with 1/f structure extending to faster, smaller and deeper dynamics in microtubule structures inside neurons. Accordingly, we also claim that EEG derives from ‘beat’ frequencies of these faster dynamics. After all these years, the origin of EEG rhythms remains unknown, and we’ve offered a solution.
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MC Specifically, they claim the microtubules are quantum computers
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SH True, but before that step we consider microtubules as classical computers/information processing devices. For example we claim microtubules encode and store memory (another mystery solved by microtubules).
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MC …that grant a person the ability to perform non-computable computations (and Penrose claims these kinds of computations are necessary for things like mathematical understanding).
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SH True, but we include understanding in general (not just mathematical understanding), as well as connecting to the fine scale structure of the universe, e.g. to solve the ‘hard problem’ of subjective experience. These latter points are a bit further in the future in terms of being tested compared to more accessible issues, but do illustrate the breadth, depth and magnitude of our theory.
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MC The main critiques of their theory are: it relies on future results in quantum gravity that don’t exist;
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SH This is false. Penrose ‘objective reduction’ (‘OR’), the claim that collapse of the wave function occurs at E=h/t, is testable, and is indeed being tested in a research program by Dik Boouwmeister, for example.
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MC …there is no empirical evidence that microtubules are relevant to the function of the brain;
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SH False. To quote John McEnroe, “you can’t be serious”. At the very least, microtubules serve to grow, form and regulate neuronal processes (axons and dendrites) and synapses, and enable transport of precursors in synaptic plasticity. Coding on microtubules by placement of tau proteins serves as traffic signals for motor proteins to deliver cargo to specific synaptic locations.
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MC …work in quantum decoherence also makes it extremely unlikely that the brain is a quantum computer;
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SH False. Bandyopadhyay’s group has shown quantum states in microtubules as long as 0.1 milliseconds, long enough for quantum computations.
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MC even if a brain could somehow compute non-computable functions it isn’t clear what this has to do with consciousness.
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SH Non-computability avoids algorithmic determinism and opens the door to free will. But aside from that, evidence now clearly points to microtubules mediating effects of anesthetics which specifically erases consciousness while sparing non-conscious functions.
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MC Would you say these are fair criticisms of their theory and are there any other criticisms you see as relevant?
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Scott Aaronson (SA) Yes, I think all four of those are fair criticisms!
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SH I strongly disagree. See above.
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SA I could add a fifth criticism: Penrose’s case for the brain having non-computational abilities relies on an appeal to Gödel’s Incompleteness Theorem, to the idea that no machine working within a fixed formal system can prove the system’s consistency, whereas a human can “just see” that it’s consistent. But like most mathematicians and computer scientists, I don’t agree with that argument, because I think a machine could show all the same external behavior as a human who “sees” a formal system’s consistency.
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SH External behavior? Yes, but that ignores consciousness. The behaviorists made consciousness a dirty word for much of the 20th century, the ‘dark ages’ of brain science, and you’re reverting to that era. In any case, microtubule quantum processes mediate consciousness (e.g. as shown by anesthetic studies) whether its non-computational or not.
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SA So then, the argument devolves into one about indescribable inner experiences, of “just seeing” (for example) that set theory is consistent.
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SH Indescribable? Inner experience is describable by the subject; it’s just not observable to someone else (like other quantum systems). Scott, come out of the dark ages.
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SA But if we wanted to rest the case on indescribable inner experiences, then why not forget about Gödel’s Theorem, and just talk about less abstruse things like the experience of falling in love or tasting strawberries or whatever?
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SH We do. That’s the so-called ‘hard problem’ as described by Chalmers. We claim ‘qualia’, raw components of conscious experience, are fundamental, irreducible components of the universe, like mass, spin or charge. Penrose OR connects quantum processes in microtubules to qualia embedded in the universe.
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MC (to SA) Your own work in this field attempts to show the relevance of quantum mechanics to consciousness without requiring us to abandon what we know from neuroscience.
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SH Penrose and I abandon NOTHING from what is known about neuroscience. We do ignore speculative assumptions which have no basis in fact. Our theory is consistent with all known facts about the brain.
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SA To my mind, one of the central things that any account of consciousness needs to do, is to explain where your consciousness “is” in space, which physical objects are the locus of it.
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SH It’s in the ‘Meyer-Overton quantum underground’, a region of non-polar pi electron resonance buried inside microtubules and other biomolecules, defined by the Meyer Overton correlation which specifies sites where anesthetics act to erase consciousness.
My colleagues Travis Craddock, Jack Tuszynski and I have shown how anesthetics dampen terahertz dipole oscillations therein. See http://www.ncbi.nlm.nih.gov/pubmed/25714379
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I’ll stop here, but note you discuss free will. Please see my article
‘How quantum brain biology can rescue conscious free will’.
http://www.ncbi.nlm.nih.gov/pubmed/23091452
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cheers
Stuart
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Stuart Hameroff MD
Professor, Anesthesiology and Psychology
Director, Center for Consciousness Studies
Banner-University Medical Center
The University of Arizona, Tucson, Arizona
Stuart, thanks for your thoughts. My interview with Scott was focused mostly on his unique thoughts about quantum mechanics and consciousness so I didn’t delve do deep into specific criticisms of Orch-OR. But given you called me out on my criticisms of Orch-OR in the introduction to the interview, let me delve into them a little deeper. To make my response easier to read I am going to try address all your comments in a narrative way rather than trying to divide them up.
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As a neuroscientist I am very skeptical about the relevance of quantum mechanics in describing the function of the brain or consciousness. It is important to understand this statement correctly. Of course quantum mechanics is needed to describes the inner workings of the small scale structures (atoms, molecules) that make up cells, so what I mean here is that when modeling neurons, we can do this using classical physics and do not need to consider things such as superposition or entanglement. There is an ongoing debate in the foundations of quantum mechanics about the quantum to classical transition. I know you are familiar with Tegmark’s 1999 paper (see references at the end) where he suggested decoherence effects significantly limit any quantum effects in the brain. You mentioned the recent research by Bandyopadhyay’s group showing quantum effects up to 0.1 milliseconds in microtubules, but see Reimers et al. 2014 and McKemmish et al. 2009 who challenge these results. Ultimately the scale of quantum effects in the brain is still an open empirical question, but I think the default position is still to remain very skeptical without more evidence. Orch-OR could be classified as a theory of wave-function collapse. I agree there are empirical predictions from Orch-OR theory regarding collapse of the wave function in a system with a certain mass. However, these predictions have not been tested and would violate the standard formulation of quantum mechanics which has faced all challenges for the last 85 years, so again the default position is to remain very skeptical of these claims.
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I think there are much deeper problems with Orch-OR that have nothing to do whether it’s hypotheses about quantum mechanics are correct. Specifically, I stand by my statement that Orch-OR is a theory that abandons conventional wisdom in neuroscience. In itself there is nothing wrong with a theory that challenges conventional wisdom, and that is how science is able to advance from one paradigm to another as suggested by Thomas Kuhn. Yet this places a huge burden on any such theory: it must have an amount of evidence proportional to the evidence supporting the prior theory. Let’s call the conventional wisdom in neuroscience the “neural theory” of the brain. In brief, let me describe the tenets of this theory. Sensory input from the environment is translated into electrical impulses at the sense organs. In organisms with primitive nervous systems this is translated directly to nerves controlling behavior. In more complex organisms, between input and output there are multiple layers of neurons where more advanced information processing occurs. Brains can now be modeled very accurately with neural network models. With the neural theory neuroscientists have all they need to model how the brain generates behavior. When Penrose wrote his first book “The Emperor’s New Mind” in 1989 this was during the second AI winter where there was a lot of skepticism about AI (including connectionism models) explaining the behavior of the brain. Today it is fair to say that this AI winter is long past. Deep learning networks (which capture only part of the complexity of complex nervous system) are changing the world. There are few claims today about what a computer (including a neural network) can’t do. The next big test for a AI seems to be natural language understanding and passing the Turing Test. Therefore, there is no longer any great motivation to posit anything beyond classical computers to explain all the human behavior. This is also a good time to bring up the difference between classical and quantum computers. Quantum computers work differently than classical computers by exploiting the property of superposition in systems small enough to avoid decoherence. There has been a huge amount of recent work on quantum computers which has shown just how difficult it is to isolate a system from the environment to avoid quantum decoherence, which again goes back to Tegmark’s skepticism that anything like this could exist in the brain. Even more challenging is how such a system could communicate any information processing with the rest of the brain (again just look at the challenges in quantum computing). And finally, it has proven very difficult to develop algorithms that harness the abilities of quantum computers in order to do anything useful. Classical computers can do any computations a quantum computer can do: the only advantage of a quantum computer is speed. By exploiting the properties of superposition quantum computers can have an exponential advantage in speed over classical computers. But as a stated in the interview, quantum computers have no special powers to compute non-computable functions. There simply aren’t algorithms that allow non-computable functions to be solved (this is a basic proof in computability theory). In terms of Penrose’s claim that quantum computers could allow some kind of direct understanding of mathematics or anything else, this is pure mysticism. A better explanation of “understanding” is that billions of neurons and trillions of connections form representations and information that model the process that is being understood.
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What I said about microtubules was correct, i.e. they are involved in nucleic and cell division, organization of intracellular structure, and intracellular transport, as well as ciliary and flagellar motility. When I stated they had no role in the function of the brain, obviously I meant the brain’s function of information processing. Of course microtubules support the cell itself. It also goes without saying that I was talking about organisms with a nervous system. Single cell organisms have their own mechanisms for sensing and responding to the environment. Microtubules may very well a role to play in this (I don’t enough to say one way or another), but this has nothing to do with their role in the nervous system. Let me also briefly mention memory. Once again, neuroscientists don’t need to invoke any fanciful mechanisms for memory. Rapid advances are being made in understanding the mechanisms behind memory (see a great review paper by Bailey, Kandel, and Harris 2015). There is no evidence that microtubules or quantum mechanics play any role in memory.
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So now let’s talk consciousness, which is course the main motivation for Orch-OR. Consciousness is clearly correlated with brain function, and given that the neural theory can explain behavior, what is the motivation to invoke any non-neural mechanisms for consciousness? I have some sympathy with David Chalmers and his formulation of the hard problem of consciousness. The best way to understand the hard problem is to think of two identical worlds with one exception: in one world, consciousness exists, and in the other everyone is a philosophical zombie with identical behavior but no inner life. The hard problem suggests that while neurons are correlated with consciousness, they cannot be consciousness (i.e. the identity theory is wrong). Yet solutions to the hard problem don’t require abandoning the neural theory. Instead, they lead to theories like neutral monism and property dualism or perhaps panpsychism. Panpsychism posits that consciousness is a fundamental part of the universe as you suggested, but this doesn’t support Orch-OR in any way. Even if consciousness comes from fundamental particles (which would be better labeled as proto-consciousness), the kind of consciousness we care about is still only associated with the activity of neurons within our brains (see my paper Cerullo 2015). So Orch-OR theory is not a solution to the hard problem of consciousness. If microtubules did happen to be involved in information processing, we can imagine one world where this leads to consciousness and another where it doesn’t and we are back to philosophical zombies.
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I stand with my original claim that Orch-OR requires us to abandon 200 years of neuroscience. Anyone interested in the scientific study of consciousness needs to first and foremost pay attention to neuroscience; that is where 99% of the action is (with the remaining 1% in philosophy, mainly in helping to interpret the new findings in neuroscience). There are major advances made every day in neuroscience as we begin to understand and model the connectome. There is no longer any need to posit any extraordinary physical mechanisms to explain consciousness.
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References:
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Bailey CH, Kandel ER, Harris KM. Structural Components of Synaptic Plasticity and Memory Consolidation. Cold Spring Harb Perspect Biol 2015.
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Georgiev, Danko (2006). Falsifications of Hameroff-Penrose Orch OR Model of Conscious-ness and Novel Avenues for Development of Quantum Mind Theory. PhilSci Archive
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Cerullo M. The Problem with Phi: A Critique of Integrated Information Theory. PLoS Comput Biol 11(9): e1004286. doi:10.1371/journal.pcbi.1004286
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Christof Koch & Klaus Hepp. Concept Quantum mechanics in the brain. Nature 440, 611 (30 March 2006) | doi:10.1038/440611a
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Christof Koch and Klaus Hepp. The relation between quantum mechanics and higher brain functions: Lessons from quantum computation and neurobiology. http://www.theswartzfoundation.org/papers/caltech/koch-hepp-07-final.pdf
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McKemmish LK, et al., “Penrose–Hameroff orchestrated objective-reduction proposal for human consciousness is not biologically feasible,” Physical Review E 80: 021912 (2009)
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Reimers et al. Weak, strong, and coherent regimes of Fröhlich condensation and their appli-cations to terahertz medicine and quantum consciousness.Proceedings of the National Academy of Sciences Online, Feb. 2009.
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Reimers JR, McKemmish LK, McKenzie RH, Mark AE, Hush NS. The revised Penrose–Hameroff orchestrated objective reduction proposal for human consciousness is not scientifically justified. Comment on “Consciousness in the universe: A review of the ‘Orch OR’ theory” by Hameroff and Penrose. Phys Life Rev 2014;11(1):101–3.
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Max Tegmark, “The Importance of Quantum Decoherence in Brain Processes,” Phys. Rev. E 61 (2000) 4194-4206
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Francisco Villatoro. On the quantum theory of consciousness. http://mappingignorance.org/2015/06/17/on-the-quantum-theory-of-consciousness/
Dear Michael
Thanks for your comments. Please see my replies interspersed below. I haven’t dropped anything, so its rather long. I’d appreciate further responses
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Stuart
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MC
Stuart, thanks for your thoughts. My interview with Scott was focused mostly on his unique thoughts about quantum mechanics and consciousness so I didn’t delve do deep into specific criticisms of Orch-OR. But given you called me out on my criticisms of Orch-OR in the introduction to the interview, let me delve into them a little deeper. To make my response easier to read I am going to try address all your comments in a narrative way rather than trying to divide them up.
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As a neuroscientist I am very skeptical about the relevance of quantum mechanics in describing the function of the brain or consciousness. It is important to understand this statement correctly. Of course quantum mechanics is needed to describes the inner workings of the small scale structures (atoms, molecules) that make up cells, so what I mean here is that when modeling neurons, we can do this using classical physics and do not need to consider things such as superposition or entanglement.
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SH
What you’re modeling are ridiculously poor carton versions of neurons. You only consider surface membrane effects, including synaptic transmissions.
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Its probably better to consider two claims in Orch OR. One is that microtubules (particularly mixed polarity networks of microtubules in dendrites and soma of layer 5 pyramidal neurons) process information necessary and relevant to cognition, memory, language and consciousness.
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The second claim is that for Orch OR these microtubule processes involve mesoscopic quantum states for durations of (at least) ten millionths of a second (10^-7 sec). Coherence has already been shown for coherence of 0.1 milliseconds or longer (10^-4 secs), so that part is already proven. The details are in our review paper
http://www.sciencedirect.com/science/article/pii/S1571064513001188.
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MC
There is an ongoing debate in the foundations of quantum mechanics about the quantum to classical transition. I know you are familiar with Tegmark’s 1999 paper (see references at the end) where he suggested decoherence effects significantly limit any quantum effects in the brain.
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SH
We refuted Tegmark in the same journal in which he published a year later (see Hagan et al, 2001). Tegmark calculated a microtubule decoherence time of only 10^-13 secs, but he used a superposition separation distance of 24 nanometers, a term in the denominator of the decoherence time formula. In Orch OR the separation is the Fermi length, 7 orders of magnitude smaller, correcting microtubule decoherence time to 10^-6 secs. We found a few other mistakes which brought our calculated decoherence time to 10^-4 secs, later shown experimentally by Bandyopadhyay’s group (all references are in the 2014 Orch OR review paper). Tegmark refuted his own model, not ours.
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MC
You mentioned the recent research by Bandyopadhyay’s group showing quantum effects up to 0.1 milliseconds in microtubules, but see Reimers et al. 2014 and McKemmish et al. 2009 who challenge these results.
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SH
Please see our specific replies to these guys in our 2014 review paper. Sir Roger and I wrote an entire appendix devoted to their ridiculous assertions. Their (Reimers/McKemmish – RM) main points:
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RM
Conformational switching between 2 states of tubulin (component protein in microtubules) is too macroscopic, would require chemical energy, and could not be in quantum superposition of both states.
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SH
We agree completely. We did use cartoons of tubulin changing shape in early papers, but Orch OR calculations were always based only on Fermi length changes accompanied by dipole oscillations in pi resonance chains.
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RM
A single pi resonance cloud, e.g. a benzene ring (also found in aromatic amino acid rings inside tubulin) cannot be a qubit. It cannot adopt 2 distinct states, and superposition of both states.
It is, essentially, already a superposition of both states.
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SH
We agree. We propose chains of such pi resonance clouds. Each ring forms an induced dipole which couples to neighboring dipoles by van der Waals forces, and coupled rings oscillate at 10^12 Hz. Orientations correlate with information states, and geometric lattice qubits. It takes two or more to tango. You need chains of pi resonance cloud in what we call the ‘quantum underground’ inside proteins and other biomolecules.
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RM
Based on our (RM’s) Hamiltonian model of a microtubule as a linear chain of tubulin, we (RM) see only simple condensation, not truly quantum BE condensation, or Frohlich coherence.
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SH
Well, Duh. A chain of proteins is not a cylindrical lattice following Fibonacci geometry, already shown to have quantum resonances in terahertz, gigahertz, megahertz and kilohertz by Bandyopadhyay et al.
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In 1992 Alexi Samsonovich et al developed a Hamiltonian of a microtubule based on a lattice plane wrapped in a cylinder, and torus. They found Frohlich coherence and resonance patterns matching experimentally observed attachment sites for microtubule-associated proteins (MAPs) such as tau, the culprit in Alzheimers disease.
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RM are a group of eminent biophysicists, but they completely struck out in attacking Orch OR. So did all the others in your reference list of Orch OR critics. We answer them all in our review.
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MC
Ultimately the scale of quantum effects in the brain is still an open empirical question, but I think the default position is still to remain very skeptical without more evidence.
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SH
The default position treats the brain as a zombie-like computer. There is more evidence for quantum effects, and consciousness in microtubules, than for any other theory of consciousness. Correct me if I’m wrong please.
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MC
Orch-OR could be classified as a theory of wave-function collapse.
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SH
Actually, OR is the theory of collapse, each one giving a simple experience, or quale, each a moment of random, disconnected experience, like the sounds, notes and tomes of an orchestra warming up. Brain microtubules ‘orchestrate’ OR events into consciousness, like music. This is happening in microtubules inside neurons, bubbling up to influence and control membrane and synaptic effects. Orch OR is a theory of consciousness.
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MC
I agree there are empirical predictions from Orch-OR theory regarding collapse of the wave function in a system with a certain mass. However, these predictions have not been tested and would violate the standard formulation of quantum mechanics which has faced all challenges for the last 85 years, so again the default position is to remain very skeptical of these claims.
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SH
As I said, they are being tested by Boouwmeister. Quantum mechanics is incomplete, and needs a resolution to the measurement problem, and the observer problem. Orch OR solves both, and avoids multiple worlds.
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MC
I think there are much deeper problems with Orch-OR that have nothing to do whether it’s hypotheses about quantum mechanics are correct. Specifically, I stand by my statement that Orch-OR is a theory that abandons conventional wisdom in neuroscience.
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SH
I stand by my statement that Orch OR abandons nothing from conventional ‘wisdom’, and merely adds a deeper level.
Look at Naundorf et al, 2006. They showed cortical neurons in awake animals have spike-to-spike variability, suggesting some influence from within the neuron. That’s where consciousness could act.
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MC
In itself there is nothing wrong with a theory that challenges conventional wisdom, and that is how science is able to advance from one paradigm to another as suggested by Thomas Kuhn. Yet this places a huge burden on any such theory: it must have an amount of evidence proportional to the evidence supporting the prior theory.
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SH
Orch OR can bear the burden, and has more experimental supportive evidence than any other theory by far. If you disagree, tell me why please.
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MC
Let’s call the conventional wisdom in neuroscience the “neural theory” of the brain. In brief, let me describe the tenets of this theory. Sensory input from the environment is translated into electrical impulses at the sense organs. In organisms with primitive nervous systems this is translated directly to nerves controlling behavior. In more complex organisms, between input and output there are multiple layers of neurons where more advanced information processing occurs.
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SH
Besides eliminating consciousness, you’ve trivialized the brain. ‘More advanced processing’ indeed – how about (quantum) processes in microtubules inside neurons???
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MC
Brains can now be modeled very accurately with neural network models.
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SH
Your misconstrued gross simplification of a brain of skin-deep neurons can be accurately modeled by a computer? What can it do? And, so what?
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MC
With the neural theory neuroscientists have all they need to model how the brain generates behavior.
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SH
Really? How’s the Open Worm project going?
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MC
When Penrose wrote his first book “The Emperor’s New Mind” in 1989 this was during the second AI winter where there was a lot of skepticism about AI (including connectionism models) explaining the behavior of the brain. Today it is fair to say that this AI winter is long past.
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SH
I don’t know about AI winters, but I know a snow job when I see it.
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MC
Deep learning networks (which capture only part of the complexity of complex nervous system) are changing the world.
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SH
Yes. Christian Szegedy from Google who pioneered Inception, DeepDream etc, spoke at the Tucson conference ‘The Science of Consciousness’ last week. He talked about these low energy, very dense sub-network hidden layers and how they give mental-like images with psychedelic flavor. I asked him whether, in the context of the brain, these deeper layers might be microtubule processing. He said, ‘sure’.
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MC
There are few claims today about what a computer (including a neural network) can’t do. The next big test for a AI seems to be natural language understanding and passing the Turing Test.
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SH
Information patterns in microtubules have wedge-like branching similar to X bar structure in language. I discussed this with Noam Chomsky a few weeks ago and he liked the idea which I’ll be developing with his colleague Massimo Piatelli-Palmarini.
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MC
Therefore, there is no longer any great motivation to posit anything beyond classical computers to explain all the human behavior.
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SH
Be honest. You use the tools and access you have. Kinda like the drunk who lost his keys in the alley but is looking under the streetlight.
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MC
This is also a good time to bring up the difference between classical and quantum computers. Quantum computers work differently than classical computers by exploiting the property of superposition in systems small enough to avoid decoherence. There has been a huge amount of recent work on quantum computers which has shown just how difficult it is to isolate a system from the environment to avoid quantum decoherence, which again goes back to Tegmark’s skepticism that anything like this could exist in the brain.
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SH
Tegmark was wrong, and remains wrong, and knows zero about biology. Evidence from photosynthesis clearly shows quantum coherence in warm biological systems. Bandyopadhyay’s work shows quantum resonances in microtubules for as long as 0.1 millisecond. It’s easy in biology because of the quantum underground, pi resonance pathways shielded from polar interactions. See our paper on anesthetic effects.
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MC
Even more challenging is how such a system could communicate any information processing with the rest of the brain (again just look at the challenges in quantum computing).
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SH
Two questions here. 1) How do quantum states extend among microtubules in different brain regions (entanglement, possibly via gap junctions).
2) How do quantum states communicate for input and output with the classical world? (By oscillating between quantum and classical states with each collapse)
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MC
And finally, it has proven very difficult to develop algorithms that harness the abilities of quantum computers in order to do anything useful.
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SH
Not applicable to microtubules whose natural resonances take over, programming by inputs, memory etc encoded in microtubules. We don’t need algorithms.
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MC
Classical computers can do any computations a quantum computer can do: the only advantage of a quantum computer is speed.
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SH
Not if a quantum computer terminates/collapses by OR in which case consciousness occurs (according to theory). I asked Hartmut Neven from Google about this in his D Wave quantum computer and he said premature collapse by OR (and thus consciousness) would be a ‘problem’.
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MC
By exploiting the properties of superposition quantum computers can have an exponential advantage in speed over classical computers. But as a stated in the interview, quantum computers have no special powers to compute non-computable functions.
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SH
You’re not considering OR. Why? You have to solve the measurement problem somehow.
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MC
There simply aren’t algorithms that allow non-computable functions to be solved (this is a basic proof in computability theory).
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SH
No computation can allow a non-computable effect. Well, Duh.
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MC
In terms of Penrose’s claim that quantum computers could allow some kind of direct understanding of mathematics or anything else, this is pure mysticism. A better explanation of “understanding” is that billions of neurons and trillions of connections form representations and information that model the process that is being understood.
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SH
By whom? AI is mysticism.
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MC
What I said about microtubules was correct, i.e. they are involved in nucleic and cell division, organization of intracellular structure, and intracellular transport, as well as ciliary and flagellar motility. When I stated they had no role in the function of the brain, obviously I meant the brain’s function of information processing. Of course microtubules support the cell itself. It also goes without saying that I was talking about organisms with a nervous system. Single cell organisms have their own mechanisms for sensing and responding to the environment. Microtubules may very well a role to play in this (I don’t enough to say one way or another), but this has nothing to do with their role in the nervous system.
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SH
So evolutionarily speaking, you’re saying that the primary information processing system in lower organisms plays no role in information processing at higher systems? I suppose that could be true if the higher system, i.e. in this case neuronal networks, could do better than the lower. But they can’t.
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MC
Let me also briefly mention memory. Once again, neuroscientists don’t need to invoke any fanciful mechanisms for memory. Rapid advances are being made in understanding the mechanisms behind memory (see a great review paper by Bailey, Kandel, and Harris 2015). There is no evidence that microtubules or quantum mechanics play any role in memory.
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SH
There’s a problem with memory as synaptic plasticity. All synaptic proteins are transient and turn over in hours to days, and yet memories last lifetimes. Its much more likely memory is encoded in microtubules. See Figure 4 in our review paper and the reference.
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MC
So now let’s talk consciousness, which is course the main motivation for Orch-OR. Consciousness is clearly correlated with brain function, and given that the neural theory can explain behavior, what is the motivation to invoke any non-neural mechanisms for consciousness?
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SH
There’s a true bait and switch. Behavior and consciousness are not the same. Behavior without consciousness is called being a zombie. You guys should have come to our conference The Science of Consciousness last week. You’d sympathize with the zombie element.
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MC
I have some sympathy with David Chalmers and his formulation of the hard problem of consciousness. The best way to understand the hard problem is to think of two identical worlds with one exception: in one world, consciousness exists, and in the other everyone is a philosophical zombie with identical behavior but no inner life. The hard problem suggests that while neurons are correlated with consciousness, they cannot be consciousness (i.e. the identity theory is wrong).
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SH
Materialist identity theory is wrong. We identify consciousness with self-collapse by OR.
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MC
Yet solutions to the hard problem don’t require abandoning the neural theory.
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SH
We’re not. We’re supplementing it where it is devoid, i.e. neuronal interiors.
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MC
Instead, they lead to theories like neutral monism and property dualism or perhaps panpsychism. Panpsychism posits that consciousness is a fundamental part of the universe as you suggested, but this doesn’t support Orch-OR in any way.
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SH
Orch OR follows neutral monism. Spacetime geometry gives rise to both matter and experience with each collapse. Panpsychism is lame because it refers to matter, not events, and doesn’t specify level (molecule, atom, proton, quark….). In any case it would encounter quantum mechanics.
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MC
Even if consciousness comes from fundamental particles (which would be better labeled as proto-consciousness), the kind of consciousness we care about is still only associated with the activity of neurons within our brains (see my paper Cerullo 2015).
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SH
We characterize random, environmental OR (what you might call
decoherence) as being accompanied by random, disconnected and meaningless proto-conscious moments, like simple Whitehead occasions of experience, or tones and sounds of an orchestra warming up. The brain/microtubules orchestrate those into music, full consciousness.
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MC
So Orch-OR theory is not a solution to the hard problem of consciousness.
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SH
Yes, it is. We claim subjective experience is fundamental, irreducible, and occurs as ‘quanta’ with each OR, or Orch OR event. So yes, Orch OR does offer a solution to the hard problem.
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MC
If microtubules did happen to be involved in information processing, we can imagine one world where this leads to consciousness and another where it doesn’t and we are back to philosophical zombies.
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SH
Microtubules are involved in both classical and quantum processing, the latter of which leads to consciousness. What in the heck are you talking about with two worlds?
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MC
I stand with my original claim that Orch-OR requires us to abandon 200 years of neuroscience.
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SH
Name one fact that would need to be abandoned. Seriously. One fact. My paper on free will deals extensively with the Hodgkin-Huxley neuron.
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MC
Anyone interested in the scientific study of consciousness needs to first and foremost pay attention to neuroscience; that is where 99% of the action is (with the remaining 1% in philosophy, mainly in helping to interpret the new findings in neuroscience).
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SH
Neuroscience needs to encompass microtubules and quantum biology. Otherwise it’s neurodermatology.
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MC
There are major advances made every day in neuroscience as we begin to understand and model the connectome. There is no longer any need to posit any extraordinary physical mechanisms to explain consciousness.
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SH
Good luck finding your keys under the lamppost. They’re in the dark alley. Consciousness is in the quantum underground.
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I actually think chances for downloading consciousness into an alternative medium are most favorable with an array of microtubules without neurons. You could download and communicate by interferometry, photon echo, sonogenetics etc etc.
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To quote Karl Pribram (whom we memorialized at last week’s conference) “Don’t bite my finger; look where I’m pointing”.
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Cheers
Stuart
I will address your points individually in a moment, but I want to make a general point first that seems to be behind much of our disagreement. You seem to be shocked that anyone could doubt Orch-OR, so it might help to take a different approach and talk about what evidence I feel is necessary before I or anyone else should be convinced that Orch-OR is the correct theory of consciousness. While I think there are serious methodological and philosophical problems with Orch-OR, ultimately if you provided good evidence for Orch-OR I would take it very seriously. So let me illustrate the steps of evidence required:
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Step 0 – Show that decoherence doesn’t prevent microtubules from exhibiting quantum behavior in a living cell. The paper by Bandyopadhyay’s group is a start, but again I think there are real criticism of this work that you haven’t been fully addressed. This research also needs to be done in a more realistic environment (i.e. a living cell), and then needs to be replicated to the degree that most scientists agree it is real phenomenon. I would say you about 5% along in showing Step 0.
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Step 1a – Show that microtubules (in living cells) perform quantum computations using qubits, i.e. taking input from the environment, processing the information using qubits, and then send output signals that control behavior (in this step you show this in a single cell organism). You have made 0% progress in this step.
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Step 1b– Disprove quantum mechanics by showing that gravity (or complexity of computation since gravity alone would not really help) causes collapse of the wave function. You have made 0% progress in this step.
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Step 2 – Show that in an organism with a nervous system, microtubules are involved in the information processing conducted by the nervous system. Similar to step 1a, you would need to show that microtubules perform quantum computations, but this time from input information from other cells or the environment while then outputting this information to other cells. You have made 0% progress in this step.
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Step 3 – Show that consciousness is correlated with the computation performed in microtubules, i.e. that is that they part of the correlates of consciousness. You have made 0% progress in this step.
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Step 4 – Show that microtubules cause consciousness, i.e. show that microtubules are necessary and sufficient for any conscious process. You have made 0% progress in this step.
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Step 5 – Show that the computations performed by the microtubules disprove the causal closure of physics by allowing free will and direct access to consciousness that has nothing to with computation. Personally I don’t even see how this is possible; if you complete step 1b then the quantum collapse of the wave function is just a new law of physics and so doesn’t allow for free will or any other non-physical property like understanding (I know you want to say this process isn’t random or deterministic, but again that is quite a task to prove this as these seem to be the only two options). You have made 0% progress in this step.
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Step 6 – Show that all the above is not just contingently correlated with consciousness in our universe but that it is a necessary connection. This would maybe solve half of the hard problem of consciousness. You have made 0% progress in this step.
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I hope this helps explain my skepticism a little more, for me it just comes down to the evidence and what you need to demonstrate. OK, now let me address some of your individual points (although I answer them in no particular order).
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SH
Name one fact that would need to be abandoned. Seriously. One fact. My paper on free will deals extensively with the Hodgkin-Huxley neuron.
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MC – One fact that would be abandoned with Orch-OR is that the computational power of the brain comes from neurons. A second fact would be that the brain performs its function by computation. A third fact is that would need to abandoned is the causal closure of physics. I could go on.
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SH
Microtubules are involved in both classical and quantum processing, the latter of which leads to consciousness. What in the heck are you talking about with two worlds?
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MC – The key insight of the hard problem is that consciousness cannot be reduced to the physical, regardless of whether for physical you are talking about classical neurons or systems with quantum properties. Chalmers is trying to illustrate the difference between contingent connections in our universe vs. necessary connections in any possible world. Orch-OR would be a contingent cause of consciousness, not a necessary connection (i.e. there is no reason you could not have zombies where their microtubules control behavior like Orch-OR suggests).
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SH
Yes, it is. We claim subjective experience is fundamental, irreducible, and occurs as ‘quanta’ with each OR, or Orch OR event. So yes, Orch OR does offer a solution to the hard problem.
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MC – Claiming the consciousness is somehow fundamental seems to be the closest anyone can come to getting at the hard problem. But any theory can claim experience is fundamental, and the problems is that this is just a brute force claim. Property dualism claims consciousness is just a property of matter; monism claims consciousness is a dual aspect of whatever fundamentally makes up the universe (and all these views are also consistent with the view that neurons cause consciousness). So Orch-OR doesn’t do any better than any non-eliminativist theory in solving the hard problem, all such theories just claim consciousness just is “X”. So that is why they only half-way solve the hard problem.
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SH
We characterize random, environmental OR (what you might call
decoherence) as being accompanied by random, disconnected and meaningless proto-conscious moments, like simple Whitehead occasions of experience, or tones and sounds of an orchestra warming up. The brain/microtubules orchestrate those into music, full consciousness.
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MC – Proto-consciousness is not consciousness and there is no theory to get from one to the other (as I explained in Cerullo 2015). In fact, they could have absolutely nothing to do with each other, and for epistemological reasons I think this is probably the case. This is often called the combination problem for panpsychism, and Orch-OR doesn’t provide a solution.
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SH
Orch OR follows neutral monism. Spacetime geometry gives rise to both matter and experience with each collapse. Panpsychism is lame because it refers to matter, not events, and doesn’t specify level (molecule, atom, proton, quark….). In any case it would encounter quantum mechanics.
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MC Panpsychism can refer to any fundamental property having consciousness, not just matter. I agree that one could interpret Orch-OR as a form of neutral monism, but that label is just a brute force solution and doesn’t really help solve any of the problems of Orch-OR.
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SH
There’s a true bait and switch. Behavior and consciousness are not the same. Behavior without consciousness is called being a zombie. You guys should have come to our conference The Science of Consciousness last week. You’d sympathize with the zombie element.
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MC A big problem with Orch-OR (as well as other theories like IIT) is that they forget that the only measure of consciousness we will ever have is through behavior. That doesn’t mean that behavior is consciousness like the old philosophical behaviorists claimed, but if a theory can’t explain the behavior associated with consciousness (which Orch-OR or IIT can’t), then it can never even get off the ground. Also, I have attended and enjoyed the bi-annual Science of Consciousness Conference in Tucson since 2004. Again the problem isn’t that I don’t understand Orch-OR theory, I have heard you or Penrose talk many times. I was also at the talk last month of Christian Szegedy from google, and no, he didn’t endorse Orch-OR theory (he admitted he was no expert on consciousness and clearly had no idea of the implications or details of Orch-OR). Also, I am not an eliminativist about consciousness (so no, I would not sympathize with the zombie element), but any theory of consciousness has to explain the behavior associated with consciousness. Neuroscience can do a pretty job of explaining behavior (i.e. representations, information), but in Orch-OR all the action happens in one miracle step: in some other realm understanding and free will happens and this is translated at one instant into the collapse of the wave function. To me this is the equivalent of explaining behavior through magic.
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SH
There’s a problem with memory as synaptic plasticity. All synaptic proteins are transient and turn over in hours to days, and yet memories last lifetimes. Its much more likely memory is encoded in microtu-bules. See Figure 4 in our review paper and the reference.
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MC – That is simply incorrect. There are studies showing long term synaptic changes with long term memory (see Bailey, Kandel, and Harris 2015). There is no evidence that microtubules have anything to do with memories.
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SH
So evolutionarily speaking, you’re saying that the primary information processing system in lower or-ganisms plays no role in information processing at higher systems? I suppose that could be true if the higher system, i.e. in this case neuronal networks, could do better than the lower. But they can’t.
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MC – Yes, I am saying that the mechanisms that control behavior in a single cell organism have nothing to do with how a nervous system functions. Sorry, but I have no idea what you mean by lower or high-er organisms and your implication that lower organisms can do more than higher organisms with nerv-ous systems.
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SH
By whom? AI is mysticism.
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MC AI isn’t mysticism, we completely understand how AI works, where of course I am talking about today’s AI and not human equivalent AI, but again given all the progress that type of AI really doesn’t seem mysterious. There is still a lot of work today to understand the brain and develop Turing level AI. Orch-OR relies on mysticism in that somehow some property of (a new version) of quantum me-chanics leads to understanding and free will consciousness for free. It is the for free part that I like the least, there is a lot of hard work that explains how the brain works and how higher functions of the brain (e.g. attention, executive function) might work. Orch-OR ignores all of this research and replaces it with a mystery step where consciousness just pops out.
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SH
No computation can allow a non-computable effect. Well, Duh.
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MC – Glad you agree, so then you must agree that nothing could be a consistent theory and yet claim that non-computational things happen by brute force or magic, and since non-computational things don’t happen by any physical process, they cannot be a cause of consciousness.
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SH
Materialist identity theory is wrong. We identify consciousness with self-collapse by OR
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MC
When you state it like that (“We identify consciousness with self-collapse by OR”), Orch-OR is a physicalist theory (which is the same thing as a materialist theory) and also a form of the identity theory.
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SH
Not if a quantum computer terminates/collapses by OR in which case consciousness occurs (according to theory). I asked Hartmut Neven from Google about this in his D Wave quantum computer and he said premature collapse by OR (and thus consciousness) would be a ‘problem’.
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MC I agree with you and Neven on this, if Orch-OR is true then quantum computers won’t work like they should (because the qubits will collapse at a certain level of gravity or complexity). On the other hand, once quantum computers start to work, this will disprove Orch-OR, and I think this latter scenario is much more likely.
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SH
Not applicable to microtubules whose natural resonances take over, programming by inputs, memory etc encoded in microtubules. We don’t need algorithms.
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MC – Not true, if microtubules process information, they must be using algorithms (using the word here in the broader sense of performing a computation). That is getting back to a major problem with Orch-OR. You can’t get information processing for free, something needs to happen to accomplish this.
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SH
Two questions here. 1) How do quantum states extend among microtubules in different brain regions (entanglement, possibly via gap junctions).
2) How do quantum states communicate for input and output with the classical world? (By oscillating between quantum and classical states with each collapse)
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MC At this stage these mechanisms are pure speculation (This is Step 2 outlined previously in the Steps you need to show to convince me Orch-Or is true).
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SH
Tegmark was wrong, and remains wrong, and knows zero about biology. Evidence from photosynthesis clearly shows quantum coherence in warm biological systems. Bandyopadhyay’s work shows quantum resonances in microtubules for as long as 0.1 millisecond. It’s easy in biology because of the quantum underground, pi resonance pathways shielded from polar interactions. See our paper on anesthetic effects.
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MC Tegmark is pretty smart guy (professor of physics at MIT) and he knows what he is talking about, saying he knows zero about biology is just name calling.
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SH
Be honest. You use the tools and access you have. Kinda like the drunk who lost his keys in the alley but is looking under the streetlight.
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MC This is a poor analogy to describe the history of neuroscience, although it perhaps fits the idea of trying to make microtubules perform all the main functions of the brain.
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SH
Information patterns in microtubules have wedge-like branching similar to X bar structure in language. I discussed this with Noam Chomsky a few weeks ago and he liked the idea which I’ll be developing with his colleague Massimo Piatelli-Palmarini.
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MC Once again just speculation (Step 1a), show me some evidence.
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SH
Really? How’s the Open Worm project going?
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MC The Open Worm project is doing just fine, connectomics is becoming Big Science and there are some amazing projects going on right now. Stay tuned for many more complete mappings of the connectome (mouse, fly) in the coming years as well as whole brain emulations.
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SH
Your misconstrued gross simplification of a brain of skin-deep neurons can be accurately modeled by a computer? What can it do? And, so what?
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MC Current neural networks can do a lot, and they get better every day (the same goes for neural simulations). In fact, they are so powerful that these days fewer and fewer people doubt that the brain can be modeled as a classical computer.
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SH
Orch OR can bear the burden, and has more experimental supportive evidence than any other theory by far. If you disagree, tell me why please.
–
MC I absolutely disagree, see Steps 0 to Step 6 in my introduction to see what you need to do to convince me. This claim is so out of touch with the evidence that I really don’t know what else to say.
–
SH
Actually, OR is the theory of collapse, each one giving a simple experience, or quale, each a moment of random, disconnected experience, like the sounds, notes and tomes of an orchestra warming up. Brain microtubules ‘orchestrate’ OR events into consciousness, like music. This is happening in microtubules inside neurons, bubbling up to influence and control membrane and synaptic effects. Orch OR is a theory of consciousness.
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MC “Brain microtubules ‘orchestrate’ OR events into consciousness, like music.” Honestly I have no idea what this could possibly mean.
–
SH
The default position treats the brain as a zombie-like computer. There is more evidence for quantum effects, and consciousness in microtubules, than for any other theory of consciousness. Correct me if I’m wrong please.
–
MC You are wrong. As I stated above, the default position on how the brain works is a separate question as to whether one wishes to be an eliminativist about consciousness. Property dualism, panpsychism, emergentism, as well as monism are examples of theories of consciousness that are consistent with computational models of the brain.
–
SH
RM are a group of eminent biophysicists, but they completely struck out in attacking Orch OR. So did all the others in your reference list of Orch OR critics. We answer them all in our review.
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MC I disagree, I think they are spot on. This gets back to the process of science and evidence. Show me a paper by someone other than yourself that supports Orch-OR.
–
SH
What you’re modeling are ridiculously poor carton versions of neurons. You only consider surface membrane effects, including synaptic transmissions.
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MC Exactly, because this is what the evidence tells us matters in neurons.
Finally, a clarification. I laughed when I read your comment about the AI winter so let me explain that term a little more. Computer scientists often talk about the periods during the 70’s (the first AI winter) and a second period in the late 80’s early 90’s when people lost faith in the predictions of AI and questioned the whole computational theory of mind (https://en.wikipedia.org/wiki/AI_winter).
–
–
—Mike
Hi again everyone
I’ll respond again to Michael Cerullo. I’d like to hear from Scott Aaronson who also criticized Orch OR
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MC
I will address your points individually in a moment, but I want to make a general point first that seems to be behind much of our disagreement. You seem to be shocked that anyone could doubt Orch-OR,
–
SH
Not at all. Orch OR has been severely criticized for 21 years (without a singe blow landing).
–
I am disappointed that you and others (while disregarding Orch OR, and the contention that microtubules process classical information) have zero evidence for your own notion that classical AI can emulate brain functions including consciousness.
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MC
…so it might help to take a different approach and talk about what evidence I feel is necessary before I or anyone else should be convinced that Orch-OR is the correct theory of consciousness.
–
SH
Orch OR is a broad-based theory. As I suggested, it’ s better to break it down into two main contentions: 1) information processing in microtubules, and 2) OR-mediated quantum computations resulting in consciousness.
–
Number 1) by itself would be revolutionary, but also very logical. Already we’re hearing..’of course, its obvious – we knew it all along’.
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MC
While I think there are serious methodological and philosophical problems with Orch-OR, ultimately if you provided good evidence for Orch-OR I would take it very seriously.
–
SH
We have provided good evidence. I would take AI seriously as representing brain function leading to consciousness if you provided any evidence whatsoever.
–
MC
So let me illustrate the steps of evidence required:
–
Step 0 – Show that decoherence doesn’t prevent microtubules from exhibiting quantum behavior in a living cell. The paper by Bandyopadhyay’s group is a start, but again I think there are real criticism of this work that you haven’t been fully addressed.
–
SH
Ten years ago the idea of warm biological quantum coherence was totally unsubstantiated. Now we have photosynthesis, Bandyopadhyay etc. That’s amazing progress.
–
So, what criticism hasn’t been addressed?
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MC
This research also needs to be done in a more realistic environment (i.e. a living cell), and then needs to be replicated to the degree that most scientists agree it is real phenomenon. I would say you about 5% along in showing Step 0.
–
SH
Anirban’s latest work IS done in a neuron.
–
But that first step is a big one. Ten years ago, it would have appeared impossible by conventional wisdom. Only a few brave theorists like us dared to suggest it. Now, with photosynthesis and Anirban, we’re vindicated
–
MC
Step 1a – Show that microtubules (in living cells) perform quantum computations using qubits, i.e. taking input from the environment, processing the information using qubits, and then send output signals that control behavior (in this step you show this in a single cell organism). You have made 0% progress in this step.
–
SH
Showing quantum coherence in microtubules is the first step in this. That’s been done. The cat is out of the bag.
–
Anirban’s latest work shows sub-threshold microtubule resonances influence activity in nearby neurons.
–
MC
Step 1b– Disprove quantum mechanics by showing that gravity (or complexity of computation since gravity alone would not really help) causes collapse of the wave function. You have made 0% progress in this step.
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SH
We’re not attempting to disprove quantum mechanics which suffers from the measurement problem. We’re trying to solve the problem. The solution is being tested. That’s progress.
–
MC
Step 2 – Show that in an organism with a nervous system, microtubules are involved in the information processing conducted by the nervous system.
–
SH
It has been shown. See Dixit R, Ross H, Goldman YE, Holzbaur EL (2008) Differential regulation of dynein and kinesin motor proteins by tau. Science 319(5866)
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Synaptic plasticity depends on delivery of synaptic precursors by motor proteins moving along microtubules. Placement of tau proteins on microtubule lattices encodes for where the motor proteins should disembark and deliver their cargo to the proper synapse. When microtubules destabilize and tau is dislodged, memory and consciousness are lost (Alzheimer’s disease)
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MC
Similar to step 1a, you would need to show that microtubules perform quantum computations, but this time from input information from other cells or the environment while then outputting this information to other cells. You have made 0% progress in this step.
–
SH
Anirban’s recent work essentially shows this.
–
But the first big step – quantum coherence at sufficiently long coherence times – has been shown. We’ve made a lot more progress than you guys have. Not even close.
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MC
Step 3 – Show that consciousness is correlated with the computation performed in microtubules, i.e. that is that they part of the correlates of consciousness. You have made 0% progress in this step.
–
SH
We’ve shown how anesthetics, which reversibly erase consciousness, do so by dampening quantum oscillations in microtubules. That’s progress.
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MC
Step 4 – Show that microtubules cause consciousness, i.e. show that microtubules are necessary and sufficient for any conscious process. You have made 0% progress in this step.
–
SH
See above. Consciousness is selectively erased by anesthetics dampening microtubule oscillations..
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MC
Step 5 – Show that the computations performed by the microtubules disprove the causal closure of physics by allowing free will and direct access to consciousness that has nothing to with computation.
–
SH
Penrose non-computability may be viewed as computation in another system, e.g. at deeper scales and levels of the structure of spacetime geometry. It’s the causal closure in the brain (and its implied lack of free will) we’re concerned about.
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MC
Personally I don’t even see how this is possible; if you complete step 1b then the quantum collapse of the wave function is just a new law of physics and so doesn’t allow for free will or any other non-physical property like understanding (I know you want to say this process isn’t random or deterministic, but again that is quite a task to prove this as these seem to be the only two options). You have made 0% progress in this step.
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SH
Non-computability is neither random nor algorithmic, but it may be deterministic. Otherwise, according to you, consciousness is epiphenomenal and free will is impossible. There’s something going on in neurons other than membrane potentials triggering spikes. That’s clear from the work of Naundorf et al (2006)
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MC
Step 6 – Show that all the above is not just contingently correlated with consciousness in our universe but that it is a necessary connection. This would maybe solve half of the hard problem of consciousness. You have made 0% progress in this step.
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SH
We’ve described how it could happen. That’s progress. You’re demanding a ridiculous amount of ‘proof’ when your side has zero evidence. If you guys channeled all your resrach into microtubules and quantum biology you could actually get somewhere instead of making promises you cant keep.
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MC
I hope this helps explain my skepticism a little more, for me it just comes down to the evidence and what you need to demonstrate.
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SH
We’ve made progress which you’re ignoring. You haven’t.
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MC
OK, now let me address some of your individual points (although I answer them in no particular order).
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SH
Name one fact that would need to be abandoned. Seriously. One fact. My paper on free will deals extensively with the Hodgkin-Huxley neuron.
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MC – One fact that would be abandoned with Orch-OR is that the computational power of the brain comes from neurons.
SH
All those neurons have microtubules. So, no.
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MC
A second fact would be that the brain performs its function by computation.
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SH
Non-conscious processes may be computation (including that in microtubules), but you have zero evidence that consciousness (or even non-conscious processing occurs by neuronal computation without deeper level microtubule processing. So, no.
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MC
A third fact is that would need to abandoned is the causal closure of physics. I could go on.
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SH
Please do, but how is that a fact? We don’t abandon causal closure in physics – we just don’t limit it to the classical world.
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How are the first two facts? Three strikes and you’re out.
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SH
Microtubules are involved in both classical and quantum processing, the latter of which leads to consciousness. What in the heck are you talking about with two worlds?
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MC – The key insight of the hard problem is that consciousness cannot be reduced to the physical, regardless of whether for physical you are talking about classical neurons or systems with quantum properties.
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SH
No. No. No. The ‘hard problem’ raises the possibility that beings can behave like conscious beings without consciousness. I think that’s exactly the result of brain computation by neurons without
Orch OR (which IS physical).
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MC
Chalmers is trying to illustrate the difference between contingent connections in our universe vs. necessary connections in any possible world. Orch-OR would be a contingent cause of consciousness, not a necessary connection (i.e. there is no reason you could not have zombies where their microtubules control behavior like Orch-OR suggests).
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SH
I don’t understand what you mean in your first sentence. Any possible world? Can we stick to this one please. And you have absolutely no basis for your last sentence. If so, what is it?
–
SH
Yes, it is. We claim subjective experience is fundamental, irreducible, and occurs as ‘quanta’ with each OR, or Orch OR event. So yes, Orch OR does offer a solution to the hard problem.
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MC – Claiming the consciousness is somehow fundamental seems to be the closest anyone can come to getting at the hard problem. But any theory can claim experience is fundamental, and the problems is that this is just a brute force claim.
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SH
No, fundamental processes imply small scales, which implies quantum. Orch OR is the only biological theory which involves a specific quantum mechanism. We’re miles ahead of other theories, have some experimental verification, testable predictions, and enormous explanatory power.
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MC
Property dualism claims consciousness is just a property of matter; monism claims consciousness is a dual aspect of whatever fundamentally makes up the universe (and all these views are also consistent with the view that neurons cause consciousness). So Orch-OR doesn’t do any better than any non-eliminativist theory in solving the hard problem, all such theories just claim consciousness just is “X”. So that is why they only half-way solve the hard problem.
–
SH
See above. We characterize subjective experience as being associated with/equivalent to self-collapse of the wavefunction by OR E=h/t.
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SH
We characterize random, environmental OR (what you might call
decoherence) as being accompanied by random, disconnected and meaningless proto-conscious moments, like simple Whitehead occasions of experience, or tones and sounds of an orchestra warming up. The brain/microtubules orchestrate those into music, full consciousness.
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MC – Proto-consciousness is not consciousness and there is no theory to get from one to the other (as I explained in Cerullo 2015). In fact, they could have absolutely nothing to do with each other, and for epistemological reasons I think this is probably the case. This is often called the combination problem for panpsychism, and Orch-OR doesn’t provide a solution.
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SH
Wrong again. Panpsychism can’t solve the combination problem. Orch OR does. Each OR event occurring randomly is proto-conscious. When these events are orchestrated and entangled, the events take on meaning –full rich conscious moments.
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SH
Orch OR follows neutral monism. Spacetime geometry gives rise to both matter and experience with each collapse. Panpsychism is lame because it refers to matter, not events, and doesn’t specify level (molecule, atom, proton, quark….). In any case it would encounter quantum mechanics.
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MC
Panpsychism can refer to any fundamental property having consciousness, not just matter. I agree that one could interpret Orch-OR as a form of neutral monism, but that label is just a brute force solution and doesn’t really help solve any of the problems of Orch-OR.
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SH
It’s a broad categorization which narrows things down. I never claimed that describing Orch OR as within neutral monism solves the problem specifically. It’s the proper framework, as is Whitehead. You’re flailing.
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SH
There’s a true bait and switch. Behavior and consciousness are not the same. Behavior without consciousness is called being a zombie. You guys should have come to our conference The Science of Consciousness last week. You’d sympathize with the zombie element.
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MC
A big problem with Orch-OR (as well as other theories like IIT) is that they forget that the only measure of consciousness we will ever have is through behavior. That doesn’t mean that behavior is consciousness like the old philosophical behaviorists claimed, but if a theory can’t explain the behavior associated with consciousness (which Orch-OR or IIT can’t), then it can never even get off the ground.
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SH
Wrong. Orch OR (or at least microtubule processing) indeed explains behavior, for example that mediated through variability of spike threshold (see my paper on free will)
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MC
Also, I have attended and enjoyed the bi-annual Science of Consciousness Conference in Tucson since 2004. Again the problem isn’t that I don’t understand Orch-OR theory, I have heard you or Penrose talk many times.
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SH
You should read the paper. You seem like a smart guy. I suspect you don’t want to understand it. Here it is again
http://www.sciencedirect.com/science/article/pii/S1571064513001188
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MC
I was also at the talk last month of Christian Szegedy from google, and no, he didn’t endorse Orch-OR theory (he admitted he was no expert on consciousness and clearly had no idea of the implications or details of Orch-OR).
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SH
I didn’t ask him about Orch OR, or consciousness. I asked him whether his ‘Deep Learning/DeepDream’ networks (which include
deeper ‘hidden layers’ of high information density, and low energy consumption, so as to not slow down the overall process) could be viewed in the brain as the deeper layer of processing in microtubules inside neurons. Quantum processing would be particularly dense and low energy consumption. He said yes.
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MC
Also, I am not an eliminativist about consciousness (so no, I would not sympathize with the zombie element), but any theory of consciousness has to explain the behavior associated with consciousness. Neuroscience can do a pretty job of explaining behavior (i.e. representations, information),
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SH
Really? Outside of V1, where are the representations in the brain?
What is the information? Spikes? Dendritic LFPs? Microtubule qubits?
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MC
…but in Orch-OR all the action happens in one miracle step: in some other realm understanding and free will happens and this is translated at one instant into the collapse of the wave function. To me this is the equivalent of explaining behavior through magic.
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SH
You’re referring to the collapse mechanism, which is the culmination of quantum computation in microtubules. There are also classical computation and processing in microtubules which regulate synapses, store memory and implement logic and language. The ‘miracle step’ solves the hard problem and brings in non-computability.
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SH
There’s a problem with memory as synaptic plasticity. All synaptic proteins are transient and turn over in hours to days, and yet memories last lifetimes. Its much more likely memory is encoded in microtu-bules. See Figure 4 in our review paper and the reference.
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MC – That is simply incorrect. There are studies showing long term synaptic changes with long term memory (see Bailey, Kandel, and Harris 2015). There is no evidence that microtubules have anything to do with memories.
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SH
Aplysia neurons have microtubules too. When microtubules are disrupted, as in Alzheimer’s, memory is lost (or at least access to memory).
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SH
So evolutionarily speaking, you’re saying that the primary information processing system in lower or-ganisms plays no role in information processing at higher systems? I suppose that could be true if the higher system, i.e. in this case neuronal networks, could do better than the lower. But they can’t.
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MC – Yes, I am saying that the mechanisms that control behavior in a single cell organism have nothing to do with how a nervous system functions. Sorry, but I have no idea what you mean by lower or higher organisms and your implication that lower organisms can do more than higher organisms with nervous systems.
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SH
I didn’t say that. I’m saying that single cell organisms with no synapses are damn clever, using their microtubules for information processing. There are about a billion microtubule subunits in each neuron switching at ~10 megahertz, so 10^16 ops/sec. You’re saying that isn’t utilized. Why wouldn’t it be? Show me a functional brain without microtubules. If they are there for structural support only, why are they interrupted in dendrites and soma. Would you want your long bones fractured and expect structural support? Dendritic/somatic microtubules are arranged for optimal information processing, not structural support.
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And plant photosynthesis uses quantum coherence, so why wouldn’t that be utilized in animals for information processing?
MC
By whom? AI is mysticism.
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MC AI isn’t mysticism, we completely understand how AI works, where of course I am talking about today’s AI and not human equivalent AI,
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SH
Exactly. Human equivalent AI based on prevalent views of AI is a fantasy.
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MC
but again given all the progress that type of AI really doesn’t seem mysterious. There is still a lot of work today to understand the brain and develop Turing level AI.
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SH
If you want to understand the brain, stop treating neurons like empty cartoons. Seriously. You guys are insulting neurons, and life itself.
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MC
Orch-OR relies on mysticism in that somehow some property of (a new version) of quantum mechanics leads to understanding and free will consciousness for free.
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SH
OR was proposed by Sir Roger Penrose to 1) solve the measurement problem, 2) account for consciousness, and 3) conceptually unify quantum mechanics and general relativity.
Sir Roger is a world class physicist who has been besmirched by AI types and others who don’t like the implications of his ideas.
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MC
It is the for free part that I like the least, there is a lot of hard work that explains how the brain works and how higher functions of the brain (e.g. attention, executive function) might work. Orch-OR ignores all of this research and replaces it with a mystery step where consciousness just pops out.
–
SH
Quantum processes are low energy but not ‘free’. I don’t think classical approaches really explain how the brain works….how higher (but not conscious) functions MIGHT work.
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The mystery step solves 3 problems. It’s a logical deduction by a world class thinker.
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SH
No computation can allow a non-computable effect. Well, Duh.
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MC – Glad you agree, so then you must agree that nothing could be a consistent theory and yet claim that non-computational things happen by brute force or magic, and since non-computational things don’t happen by any physical process, they cannot be a cause of consciousness.
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SH
You twisted yourself into a pretzel on that one. Non-computational effects are proposed to occur by a physical process in spacetime geometry, not brute force or magic. Why can’t that be a cause of (or equivalent to) consciousness?
–
SH
Materialist identity theory is wrong. We identify consciousness with self-collapse by OR
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MC
When you state it like that (“We identify consciousness with self-collapse by OR”), Orch-OR is a physicalist theory (which is the same thing as a materialist theory) and also a form of the identity theory.
–
SH
Physicalist is not the same as materialist. Collapse of the wavefunction is a physical process which results in transient states of matter. Just because materialist identity theory is wrong doesn’t mean that collapse-identity theories are wrong.
–
SH
Not if a quantum computer terminates/collapses by OR in which case consciousness occurs (according to theory). I asked Hartmut Neven from Google about this in his D Wave quantum computer and he said premature collapse by OR (and thus consciousness) would be a ‘problem’.
–
MC I agree with you and Neven on this, if Orch-OR is true then quantum computers won’t work like they should (because the qubits will collapse at a certain level of gravity or complexity). On the other hand, once quantum computers start to work, this will disprove Orch-OR, and I think this latter scenario is much more likely.
–
SH
Lets find out. As you just stated, Orch OR is testable. But by E=h/t the E would have to have significant mass to reach time t in a reasonable time. The D Wave computer uses electrons, with very low mass and E. But it does illustrate that Orch OR is testable.
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SH
Not applicable to microtubules whose natural resonances take over, programming by inputs, memory etc encoded in microtubules. We don’t need algorithms.
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MC – Not true, if microtubules process information, they must be using algorithms (using the word here in the broader sense of performing a computation). That is getting back to a major problem with Orch-OR. You can’t get information processing for free, something needs to happen to accomplish this.
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SH
Encoding in microtubules plays the role of algorithms, resonances being built into the structural geometry and resonances of microtubules, kind of like self-organized criticality.
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SH
Two questions here. 1) How do quantum states extend among microtubules in different brain regions (entanglement, possibly via gap junctions).
2) How do quantum states communicate for input and output with the classical world? (By oscillating between quantum and classical states with each collapse)
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MC
At this stage these mechanisms are pure speculation (This is Step 2 outlined previously in the Steps you need to show to convince me Orch-Or is true).
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SH
You’ll probably never be convinced because your career and livelihood seem to depend on an alternative (and incorrect in my view) approach. You’re not impartial, and severely biased.
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SH
Tegmark was wrong, and remains wrong, and knows zero about biology. Evidence from photosynthesis clearly shows quantum coherence in warm biological systems. Bandyopadhyay’s work shows quantum resonances in microtubules for as long as 0.1 millisecond. It’s easy in biology because of the quantum underground, pi resonance pathways shielded from polar interactions. See our paper on anesthetic effects.
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MC
Tegmark is pretty smart guy (professor of physics at MIT) and he knows what he is talking about, saying he knows zero about biology is just name calling.
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SH
I stand by my statements which are not name calling. Please review his 2000 piece about deoherence times in microtubules, our 2001 response, and Bandyopadhyay’s work. Tegmark is completely wrong about this.
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SH
Be honest. You use the tools and access you have. Kinda like the drunk who lost his keys in the alley but is looking under the streetlight.
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MC This is a poor analogy to describe the history of neuroscience, although it perhaps fits the idea of trying to make microtubules perform all the main functions of the brain.
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SH
Find your own metaphor please. I’m talking about consciousness.
The brain is active under anesthesia without consciousness. Anesthesia acts on microtubule vibrations.
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I rest my case.
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SH
Information patterns in microtubules have wedge-like branching similar to X bar structure in language. I discussed this with Noam Chomsky a few weeks ago and he liked the idea which I’ll be developing with his colleague Massimo Piatelli-Palmarini.
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MC Once again just speculation (Step 1a), show me some evidence.
–
SH
We have an isomorphism for language. Stay tuned.
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SH
Really? How’s the Open Worm project going?
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MC The Open Worm project is doing just fine, connectomics is becoming Big Science and there are some amazing projects going on right now. Stay tuned for many more complete mappings of the connectome (mouse, fly) in the coming years as well as whole brain emulations.
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SH
So how’s the Open Worm project going? They were to have a big announcement of behavior a year ago and it didn’t happen. Even Christof Koch admits we can’t explain the worm. One useful fact which did come out of mapping C elegans is a huge number of gap junctions which we’ve used to explain inter-neuronal quantum tunneling, and synchrony, and goes against your computational model.
–
Your misconstrued gross simplification of a brain of skin-deep neurons can be accurately modeled by a computer? But what can it do? And, so what?
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MC
Current neural networks can do a lot, and they get better every day (the same goes for neural simulations). In fact, they are so powerful that these days fewer and fewer people doubt that the brain can be modeled as a classical computer.
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SH
You have a great PR program, but no results related to consciousness. If you can’t show behavior in an accurate simulation of the 302 neuron brain of a worm, how can you possibly expect to model a mammalian brain? More money wont do it. There’s a basic conceptual flaw.
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Orch OR can bear the burden, and has more experimental supportive evidence than any other theory by far. If you disagree, tell me why please.
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MC I absolutely disagree, see Steps 0 to Step 6 in my introduction to see what you need to do to convince me. This claim is so out of touch with the evidence that I really don’t know what else to say.
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SH
Our claim is indeed out of touch with conventional ‘wisdom’ which treats the neuron as an inanimate cartoon.
–
I answered your 6 steps, and I published 20 testable predictions of Orch OR in 1998 which we reviewed in our 2014 Orch OR paper. 6 have been verified, none refuted. No other theory of consciousness can even make such predictions, much less claim validation. The most recent development is that anesthesia appears to act by dampening terahertz vibrations in microtubules, slowing the 1/f cascade which otherwise leads to EEG.
–
SH
Actually, OR is the theory of collapse, each one giving a simple experience, or quale, each a moment of random, disconnected experience, like the sounds, notes and tomes of an orchestra warming up. Brain microtubules ‘orchestrate’ OR events into consciousness, like music. This is happening in microtubules inside neurons, bubbling up to influence and control membrane and synaptic effects. Orch OR is a theory of consciousness.
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MC “Brain microtubules ‘orchestrate’ OR events into consciousness, like music.” Honestly I have no idea what this could possibly mean.
–
SH
It’s a metaphor (at least). You say consciousness is a computation, and I say consciousness is more like music.
–
You mentioned the ‘combination problem, and I mentioned proto-consciousness which occurs with every random collapse occurring here, there and everywhere in the environment, what others would call decoherence. Each proto-conscious OR moment is random, meaningless and lacks memory. In microtubules, the superpositions which would lead to OR moments are organized (‘orchestrated’) by entanglement and isolation from random environment in the ‘quantum underground’ where anesthetics act, allowing cognitive processing and meaning in Orch OR moments.
–
Proto-conscious OR moments would be analagous to the sounds, notes, and tones of an orchestra warming up. Orch OR would be a symphony, or more like improvisational jazz (no conductor needed).
–
What’s there not to understand?
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SH
The default position treats the brain as a zombie-like computer. There is more evidence for quantum effects, and consciousness in microtubules, than for any other theory of consciousness. Correct me if I’m wrong please.
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MC
You are wrong. As I stated above, the default position on how the brain works is a separate question as to whether one wishes to be an eliminativist about consciousness. Property dualism, panpsychism, emergentism, as well as monism are examples of theories of consciousness that are consistent with computational models of the brain.
–
SH
I’m not wrong. Your account is as clear as mud. What do any of those have to do with the brain? Please provide any evidence that consciousness comes solely from computation among neurons without involving their internal microtubules. Any evidence whatsoever.
–
RM are a group of eminent biophysicists, but they completely struck out in attacking Orch OR. So did all the others in your reference list of Orch OR critics. We answer them all in our review.
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MC
I disagree, I think they are spot on. This gets back to the process of science and evidence. Show me a paper by someone other than yourself that supports Orch-OR.
–
SH
First, show me how they are spot on. Seriously. Name one claim they make about Orch OR that is correct. Just one. Our reply to them specifically is here. http://www.sciencedirect.com/science/article/pii/S1571064513001917
Unfortunately Elsevier is charging for this even though we paid for Open Access. If someone wants to see it, email me please.
–
I get papers every day which support Orch OR.
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SH
What you’re modeling are ridiculously poor carton versions of neurons. You only consider surface membrane effects, including synaptic transmissions.
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MC Exactly, because this is what the evidence tells us matters in neurons.
–
SH
What evidence? It’s what is easily measurable, not necessarily what matters. For example anesthesia acts on microtubules, not on GABA receptors as is usually suggested.
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MC
Finally, a clarification. I laughed when I read your comment about the AI winter so let me explain that term a little more. Computer scientists often talk about the periods during the 70’s (the first AI winter) and a second period in the late 80’s early 90’s when people lost faith in the predictions of AI and questioned the whole computational theory of mind (https://en.wikipedia.org/wiki/AI_winter).
–
SH
Thanks. It says:
“The field has experienced several hype cycles, followed by disappointment and criticism, followed by funding cuts, followed by renewed interest years or decades later.”
–
Its like the Myth of Sisyphus.
–
SH
I don’t dislike AI. We have great smart alarms in our anesthesia machines, phones etc. But consciousness???? Nah, no way.
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If people want to preserve their consciousness/brains, they should invest in microtubule research
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Stuart
MC …work in quantum decoherence also makes it extremely unlikely that the brain is a quantum computer;
“There is nothing else except these [quantum] fields: the whole of the material universe is built of them.”
“Physicists talk about two kinds of fields: classical fields and quantum fields. Actually, we believe that all fields in nature are quantum fields. A classical field is just a special large-scale manifestation of a quantum field.”
Dyson, Freeman J., “Field Theory,” pp. 58-60, Scientific American, 188: 1953.
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The brain is presumably a material thing; it is, therefore, a set of quantum fields.
The brain’s computations are therefore quantum field processes.
This is “why” matrix models of NNs recapitulate Heisenberg’s formulation of QM.
Or, neural form follows quantum function.