My internal understanding of Penrose's "hypothesis" is that there are structures in the brain that relate individual quantum events to macroscopic neurological processes, in a way not explained by the usual aggregation of quantum events into chemical behavior.
I'm very skeptical of this because nothing I've read has proposed any mechanism whereby it could evolve, nor any reason why these events should related to "consciousness" as opposed to any other mental process.
Admittedly, I haven't spent a whole lot of time looking into it, because time is limited and the history of science is littered with enough great scientists who latch on to mysticism (Newton being a prominent example) that I don't assume that everything coming from a recognizable name is worth exploring.
kevinpet says>"...nothing I've read has proposed any mechanism whereby it could evolve..."[italics mine]
If a biochemical mechanism exists then it is possible for it to be conscripted in evolution. Its not as if something called "evolution" sits around waiting for permission (and from whom and when?). Instead, a gene is modified randomly and blam a new mechanism occurs (or doesn't, mostly) which either enhances replication and persists in the genome or doesn't. In the long run you'd expect all chemical pathways possible to be eventually probed many, many times by evolution.
That's only true if the space of possible pathways is small enough for evolution to perform a random search of all of them in a realistic timescale, and they're all more or less equally probable.
>Whether access to an rng is a prerequisite for consciousness is another question...
Wouldn't free will necessarily require "true" random number generation? If there existed any equation such that it could always perfectly predict what something would choose, then it seems no choice is really being made. Assuming that's true, and assuming free will is a necessary component of consciousness, then it follows that probabilistic phenomena is a requirement for conscious behavior. This begs the question, "Do people have free will?", which isn't any easier to answer. But hey, if it doesn't exist, then you really can't blame me for thinking it does.
Since adding noise is a critical part in many neural network training models, it is entirely possible that an at-hand source of randomness is highly useful.
Drugs that reduce the accessibility of this randomness by biasing the signal pathways (or something) might be an interesting research vector.
>> Since adding noise is a critical part in many neural network training models
Our brains do not work exactly like neural network models. Neural Networks are a model, on how nervous systems could work. It doesn't follow, that nature has implemented them the same way.
There is no need for the human brain to produce noise with some arbitrary process. There is more than enough noise in the human brain... Every single neuron is a powerful noise-filter[0], that seemingly can generate signals when the "correct" noise-signal is filtered.
>> Drugs that reduce the accessibility of this randomness by biasing the signal pathways
The randomness you are talking about is way the brain operates under normal circumstances[1]... so no, it wouldn't be beneficial, since we cannot discern signal from noise in any meaningful way [2].
IANAP but my understanding of a lot of psychiatric drugs is that they do just this, they dampen brain activity which may be analogous to what you're describing.
> nothing I've read has proposed any mechanism whereby it could evolve
If quantum effects are at play in the evolutionary environment, then that is the mechanism. It seems pretty self-evident IMHO.
Some random adaptation introduces a sensitivity that allows that mutation to prosper and reproduce.
It's very easy to say that because you can't perceive quantum effects at the level of your personal experience, that their effect on selection is negligible, but this is a mistake a lot of anti-evolutionists take .. but over the course of millions or billions of years such effects could be highly significant.
This article covered more than I was expecting, but still manages to squeeze a small amount of substance into a relatively large article. Here's a tl;dr:
- Penrose and Hameroff postulate microtubules might have quantum mechanical behavior in their Orch-OR hypothesis. This hypothesis was refuted by Max Tegmark in the 90s. Penrose doesn't care and keeps preaching his hypothesis, and has not put forth any new scientifically compelling arguments in the past 2 decades.
- Photosynthesis is shown to be quantum mechanical. I'm not sure quantum mechanical behavior in plants is the best argument that quantum mechanics are responsible for consciousness.
- Fischer hypothesizes that phosphate ions in biological cells might exhibit distinctly quantum mechanical behavior, but is wary about any link to "quantum consciousness".
This is pretty much all of the substance of the article.
Even if there were a conclusively demonstrated link between quantum mechanical behavior in human cells (there isn't), using that to argue that our brains are quantum computers and that consciousness is a fundamentally quantum phenomenon would be a huge non sequitur.
Furthermore: "Photosynthesis is shown to be quantum mechanical" - well, yes, just like everything else in physics, with the possible exception of those issues, like black holes, where gravity is dominant. The quantum-mechanical basis of chemistry has been included in high-school chemistry curricula for at least half a century, so it would be quite remarkable if photosynthesis were a exception.
While it is possible that the human mind has no classical-approximation explanation, the equating-of-ignorance argument, stated in the article's subtitle, is no reason to think it is so (and quantum mechanics is much better understood than the human mind, anyway.)
All chemistry is ultimately quantum, same with rocks and everything up to celestial bodies (meaningfully, the moon Hyperion decoheres). For most of calculations though classical models are good enough, vast majority of chemical reactions behave as if molecules were newtonian springs. When people talk of quantum effects in chemistry they really mean it. In case of photosynthesis the basic molecule's efficiency was found hinging on stuff that is very quantum. This was described by Gregory Engel et al. Alan Aspuru-Guzik interprets some of what's happening as a realization of quantum computation running a tree-walking algorithm.
The wider conclusion is that living organisms do evolve around quantum effects (if the molecule existed a priori somehow) or maybe even evolve to the point of reaching and then harnessing them (making the molecule).
Now to what's Penrose about. Seldom anybody actually reads the guy or know the context. He was after the computational theory of mind. Not necessarily looking for a theory, but sneering at one big non-theory. This is in context of the 80's with unhinged stuff coming from the AI community (same as today). He was wondering if brain could really be this reducible and a known model of computation (he hasn't done a good review) from the physical point of view. For him a full logical reductionism necessiated excissing the measurement problem (the basic point goes back to Niels Bohr who thought biology cannot be entirely physics because of this). So he proposed a crude version that fleshes out measurement as a real physical process. His idea has the main upside of removing both quantum and AI mysticism.
This received angry and mostly off-topic response based on caricature summaries like elsewhere in this thread. Of course lending themselves to such caricatures says a lot about writing if not the ideas, but it's an honest try that ain't entirely silly and without upsides. The microtubules guy is someone else who Penrose was just happy to see come and collaborate with later. He'd be happy with any kind of other stuff, such as from the original article. BTW the author is Philip Ball, a long time editor of the Nature journals, and he's got a new book out about interpretations of quantum mechanics that is really superb to anything else on the market by far (that is could be better but isn't worthless).
My problem with his theory is not that consciousness in the brain might be dependent on quantum effects, but that he seems to conclude that this makes it impossible for computers to have consciousness. Quantum computers can be simulated by classical computers.
That's a significant goalpost move. From debating particular mechanisms and postulated inevitability of AI, to assuming full blown strong Church-Turing-Deutsch principle and moving from there. Along with moving whole discussion from practical concerns into philosophy and really arguing from the thesis, at which point most people lose interest.
They are referring to the finding that plants utilize coherence to transport photons efficiently to reaction centers to be converted to chemical energy. A quantum trick not thought possible in biological settings.
My issue is with how the author is using this fact as if it were an argument for the proposition that consciousness cannot be explained without invoking quantum 'weirdness' (and, conversely, will be explained with it.)
The way the author presents it seems calculated to suggest that it is a more relevant fact to his claim than it is, mainly by leaving out any context and details that show it is not.
This is not even the worst case, which I think goes to this: "Might it be that, just as quantum objects can apparently be in two places at once, so a quantum brain can hold onto two mutually-exclusive ideas at the same time?"
Note how the author phrases it in a way that would allow him to brush it off as mere speculation or analogy if he is challenged on it - a case of the motte-and-bailey tactic. I think this passage qualifies as being "not even wrong", and the whole article clearly fits Feynman's definition of cargo-cult 'science'.
Meanwhile, I have a computer that can do two tasks at the same time - does that mean that it is a quantum computer? I see D-Wave is selling quantum computers for upwards of $15M, but mine is available with bids starting at a mere $5M.
I completely agree. It was by and large a very good article, but could have been better if it presented the other side. I'd like to know what the counter evidence is. The author seems to imply that the other side is "in the dark" on this question, and has no hypothesis and speculation of their own.
Nuclear Spin Attenuates the Anesthetic Potency of Xenon Isotopes in Mice: Implications for the Mechanisms of Anesthesia and Consciousness.
Xenon is an elemental anesthetic with nine stable isotopes. Nuclear spin is a quantum property which may differ among isotopes. Xenon 131 (Xe) has nuclear spin of 3/2, xenon 129 (Xe) a nuclear spin of 1/2, and the other seven isotopes have no nuclear spin. This study was aimed to explore the effect of nuclear spin on xenon anesthetic potency.
CONCLUSIONS: Xenon isotopes with nuclear spin are less potent than those without, and polarizability cannot account for the difference. The lower anesthetic potency of Xe may be the result of it participating in conscious processing and therefore partially antagonizing its own anesthetic potency. Nuclear spin is a quantum property, and our results are consistent with theories that implicate quantum mechanisms in consciousness.
This paper describes the effect of Xenon on plants:
"Anaesthetics stop diverse plant organ movements, affect endocytic vesicle recycling and ROS homeostasis, and block action potentials in Venus flytraps"
> Xenon was effective at different levels of responses, such as seed germination, chlorophyll accumulation, ROS production and vesicle recycling.
> Plant sensitivity to anaesthetics might help to reveal
elusive mechanisms of their actions. It is puzzling how
such chemically and physically diverse compounds, including
the chemically inert gas xenon, the volatile organic solvent
ether and water-soluble molecule such as lidocaine, can induce
very similar impacts in both plants and animals.
Photosynthesis as an argument is more 'it is possible that quantum effects have a place here' - that said it is a long leap given that our retinas are technically quantum just by processing particle-wave dualities. The quantum /computing/ is what is relevant to proof of there being any 'special sauce' to the human brain vs just a bunch of parallel processing power.
Essentially the quantum effects are necessary for a quantum consciousness but are definitely not sufficient. Personally I can see one way to make that link which is quite a long-shot.
Given what little I know from quantum computing and cryptography comparing parallel processing solving speed relative to problem sizes vs quantum approaches would give a theoretical basis for distinguishing the /computing/ aspects.
If human brains are able to solve progressive problems with a time increase more consistent with qubit processing than non-quantum computing combined with heuristics it would hint at quantum processing power. Needless to say that is a major tall order and would probably result in most humans failing to complete period.
Non sequitur? It's like writing: I ate a salty sandwich, hence I behave like a NaCl crystal.
Or when I roll the dice careful enough, it gets deterministic. Hence the hole world is deterministic.
That's basically everyone's summary of the Penrose argument about consciousness and quantum effects. I don't think you can ascribe it to any one person.
The summary his argument against hard question AI is even better.
Human consciousness is special.
Computers don't have that specialness.
AI is therfore impossible.
Or, you know, he probes (even if without results) for things we consider "done and closed" or "needless", so we reduce any argument he makes to a huge strawman.
> This hypothesis was refuted by Max Tegmark in the 90s.
No it wasn't and Tegmarks earlier criticisms were proven fundamentally flawed. What scientifically compelling arguments has Tegmark produced for his theories?
> - Photosynthesis is shown to be quantum mechanical. I'm not sure quantum mechanical behavior in plants is the best argument that quantum mechanics are responsible for consciousness.
"Something Really Fascinating Happens When You Give Plants Anaesthetic"
> While there's a range of chemicals that can induce anaesthesia in humans, just how these unrelated compounds trigger a lack of consciousness remains somewhat unclear.
> And the mystery deepens when you consider it isn't only animals that are affected by anaesthetics – plants are, too.
...
> "That animals/humans and also plants are animated via action potentials is of great importance for our ultimate understanding of the elusive nature of plant movements and plant-specific cognition/intelligence based plant behaviour."
> Ultimately, the team thinks these similarities between plant and animal reactions to anaesthetic compounds could lead to future research where plants might function as a substitute model or test system to explore human anaesthesia – something scientists are still pretty uncertain about.
Now if I had to add a philosophical icing to the cake, I'd guess once something gets to complicated to be explained from the ground up as a consistent whole, the only way to get at it is to study what causes this whole to cease.
I think "lack of consciousness" is not a well-defined concept. Popular forms of anesthesia these days result in what appears to be a more or less conscious patient in one sense, who can respond to some stimuli, but who does not form memories or feel pain. So in retropect, when the procedure is over, it's as if it never happened. But any observer can see they weren't unconscious as in dreamless sleep.
The point being, there are many components to what we call consciousness that seem to be demonstrably separable and it doesn't help to talk as though it's all just one unified whole.
>This article covered more than I was expecting, but still manages to squeeze a small amount of substance into a relatively large article. Here's a tl;dr:
- Penrose and Hameroff postulate microtubules might have quantum mechanical behavior in their Orch-OR hypothesis. This hypothesis was refuted by Max Tegmark in the 90s. Penrose doesn't care and keeps preaching his hypothesis, and has not put forth any new scientifically compelling arguments in the past 2 decades.
"Doesn't care" as in la-la-la hands-in-the-ears, or doesn't care as in, believes the refutation is not valid, or believes that despite the refutation of that particular mechanism there's enough evidence that there's another related mechanism?
Here's how Wikipedia puts it, which is not at all as "Tegmark won", but rather like "Tagmark's claims were wrong themselves, and refuted further":
In response to Tegmark's claims, Hagan, Tuszynski and Hameroff[56][57] claimed that Tegmark did not address the Orch-OR model, but instead a model of his own construction. This involved superpositions of quanta separated by 24 nm rather than the much smaller separations stipulated for Orch-OR. As a result, Hameroff's group claimed a decoherence time seven orders of magnitude greater than Tegmark's, although still far below 25 ms. Hameroff's group also suggested that the Debye layer of counterions could screen thermal fluctuations, and that the surrounding actin gel might enhance the ordering of water, further screening noise. They also suggested that incoherent metabolic energy could further order water, and finally that the configuration of the microtubule lattice might be suitable for quantum error correction, a means of resisting quantum decoherence.
Since the 1990s numerous counter-observations to the "warm, wet and noisy" argument existed at ambient temperatures, in vitro[23][42] and in vivo (i.e. photosynthesis, bird navigation). For example, Harvard researchers achieved quantum states lasting for 2 sec at room temperatures using diamonds.[58][59] Plants routinely use quantum-coherent electron transport at ambient temperatures in photosynthesis.[60] In 2014, researchers used theoretical quantum biophysics and computer simulations to analyze quantum coherence among tryptophan π resonance rings in tubulin. They claimed that quantum dipole coupling among tryptophan π resonance clouds, mediated by exciton hopping or Forster resonance energy transfer (FRET) across the tubulin protein are plausible.[61]
In 2007, Gregory S. Engel, Professor in Chemistry at The University of Chicago, claimed that all arguments concerning the brain being "too warm and wet" have been dispelled, as multiple "warm and wet" quantum processes have been discovered.[60][62]
In 2009, Reimers et al. and McKemmish et al., published critical assessments.[19][37][45] Earlier versions of the theory had required tubulin-electrons to form either Bose–Einsteins or Frohlich condensates, and the Reimers group claimed that these were experimentally unfounded. Additionally they claimed that microtubules could only support 'weak' 8 MHz coherence. The first argument was voided by revisions of the theory that described dipole oscillations due to London forces and possibly due to magnetic and/or nuclear spin cloud formations.[6] On the second issue the theory was retrofitted so that 8 MHz coherence is sufficient to support the whole Orch-OR hypothesis.
McKemmish et al. made two claims: that aromatic molecules cannot switch states because they are delocalised; and that changes in tubulin protein-conformation driven by GTP conversion would result in a prohibitive energy requirement. Hameroff and Penrose responded to the first claim by stating that they were referring to the behaviour of two or more electron clouds, inherently non-localised. For the second claim they stated that no GTP conversion is needed since (in that version of the theory) the conformation-switching is not necessary, replaced by oscillation due to the London forces produced by the electron cloud dipole states.
> Fisher says, if the phosphorus atoms are incorporated into larger objects called "Posner molecules". These are clusters of six phosphate ions, combined with nine calcium ions.
Couldn't it be that the measurement device (or any other interacting object) "falls" into all of the possible states of the measured system, therefore we see the measurement device itself as a quantum object when we don't interact with it, but every possible "outcome" of the measurement device sees the system as classical. At a higher scale, a human being itself is an object interacting with the measurement device, and every possible "outcome" of the human being sees the device as a classical system, showing a classical system.
At least this explanation does not involve "quantum brains" nor enthropocentrism.
What you describe is really close to the "multiverse interpretation" of quantum mechanics. It is an interesting thought exercise, but it is really important to acknowledge that it is only an interpretation, mathematically equivalent to the other ones, and experimentally unconfirmable.
As to Penrose's ideas on consciousness, they are many other problems with them (see Wikipedia for a quick list of sources; or Scott Aaronson's lecture notes).
Classical mechanics cannot explain a lot of observed behavior of the dual slit experiment - for instance IIRC a single electron or photon can interfere with itself - this cannot be explained with classical mechanics or obviously ordinary experience at human scale.
All that one can deduce from this line of (mostly philosophical) investigations is that "consciousness is randomness in our behavior".
If that definition of consciousness fits you, then fine, but the whole discussion is not very productive for neuroscience. For all i know, consciousness is an undefined term.
The article doesn't mention Francis Crick, who was even more qualified to tackle the subject.
Yes, there is no proper definition of consciousness. All the "definitions" I've heard so far either don't allow you to distinguish what a rock does from what a human brain does, or they're not compatible with our understanding of physics, or both.
Hmm, I remember thinking about this several years ago, the big issue is that it's almost unfalsifiable. I remember thinking that an experiment looking at whether anesthetics (that caused loss of consciousness in neurons) also stopped quantum phenomena in said neurons. But alas, that was a hard experiment to do back then :)
Any experiment concerning consciousness is likely unfalsifiable. It's a subjective phenomenon, by definition. Even if you could get approval to futz with someone's consciousness, you have to ask them what they are experiencing.
If the experiment is double-blind and a statistically significant proportion of participants report subjective differences according to a survey, and the results can be replicated... then you're good to go.
Obviously there's the question of what it would mean which could be argued over... but if the effect is there, it means something.
The fundamental problem is that you can test whether the drug causes people to report that they're not conscious, but you can't test whether they're actually conscious or not.
I was planning to use animals actually, but yeah, at that point in time I decided against it, I didn't think I had the necessary skills to humanely handle animals for such an invasive experiment.
Like most people here, I have been thinking this quantum consciousness stuff is a lot of woo. However something new I saw in this article is the mysteriousness around the different effects of different Lithium isotopes on treating mania. That's pretty weird, as isotopes should be chemically identical.
Not really. I don't know about lithium isotopes, but there are drugs "improved" by replacing some hydrogen atoms with deuterium (an isotope of hydrogen):
https://en.wikipedia.org/wiki/Deuterated_drug
Stable isotopes of lithium: dissimilar biochemical and behavioral effects.
Lithium, which is used routinely in the treatment of mania, is composed of two stable isotopes, lithium-7 (92.58%) and lithium-6 (7.42%). Usually there is minimal physiological or biochemical differentiation between isotopes of an element, but lithium is an exception. Data derived from a variety of biochemical and behavioral experiments are reviewed to support this idea. Additionally, the clinical implications of this work are presented.
This is one of those ideas that (rightly) won't go away.
I've recently been quite inspired by Christopher Alexander's "The Luminous Ground" (2003). For those who don't know, he's an architect and mathematician [2] whose work greatly influenced object-oriented programming (he's best-known for "A Pattern Language"), and in this most recent work of his, he addresses the concept of "wholeness" head-on -- investigating what can be done to integrate the completely separate worlds of art/spirit and physics, under the belief that they can't stay separated forever... and following in the steps of thinkers like Bohm, Penrose and Mandelbrot. (I.e. he's serious, not some new-age QM crackpot.)
The print copy is sadly ridiculously expensive, but whether online or in libraries there are definitely ways to read it if you're determined...
For me, the question of consciousness is more than a question of pure mechanism. The mystery for me is the particularity/locality of experience. It's one thing to say that we have encountered these thousands of clocks, and here is exactly how they work (mechanism). It's far more mysterious to find one's entire experience suddenly located at the epicenter at one clock in particular - with seemingly no access to similar experience of other clocks. The issue of particularity is the real problem for me. And I can't see how claiming that it is imaginary helps - it's my most convincing experience.
- your attention can change an particle's experiment outcome (you choose future)
- we see quantum effects on tiny particles only
- perhaps gravity makes quantum effects for "heavy" objects impossible
Which leads to an idea that actually all objects have quantum effects but someone watches for all objects in the universe and makes choices (chooses future) ahead of us. And apparently we can feel his attention as gravity. But his wathcing power is restriced and he/she/it can't watch every particle in the world.
So to see the quantum world and to say hello to the god we should overload his attention with DDOS attack (perhaps Babylon tower experiment was about this).
Afaik 'observe' is not in the human context, it's in the measurement context. Our eyes don't change the outcome, it's that we don't know the outcome of quantum happening without measuring in some manner, and because quantum physics is essentially nature's statistics, measuring those physics themselves provides different outcomes.
As far as I understood the article, there is a possibility that our brain can choose one of experiment's outcome. So basically we do not change the outcome, but select one of possible options. And we continue living in that chosen reality after the choice.
My expectation is that as we get closer to developing an artificial mind, we will continue to discover previously unknown processes in the human mind that continue to separate it from the most advanced artificial one we have built.
There may indeed between the human mind and quantum physics, just not the one you're thinking.
Namely, that QM doesn't represent anything physical about reality at all, and ONLY encodes probabilities relating to observations; the wavefunction is only a probability calculating math tool and doesn't represent reality in the slightest.
That's not a very useful perspective, because you could say the same thing about any part of language or science. Human knowledge is an abstraction, and can only ever indirectly represent reality. (And surely, "not in the slightest" is an exaggeration.)
Quantum probability is just a generalization of classic probability. Busemeyer in his book [1] mentions several experiments in psychology that can only be explained by quantum probability [2] but not by classic one
Since the use of a quantum-theoretic framework is for modeling purposes, the identification of quantum structures in cognitive phenomena does not presuppose the existence of microscopic quantum processes in the human brain. [2]
I'm very skeptical of this because nothing I've read has proposed any mechanism whereby it could evolve, nor any reason why these events should related to "consciousness" as opposed to any other mental process.
Admittedly, I haven't spent a whole lot of time looking into it, because time is limited and the history of science is littered with enough great scientists who latch on to mysticism (Newton being a prominent example) that I don't assume that everything coming from a recognizable name is worth exploring.