Haven't read the book, but pointing to string theory and dark matter as evidence for an afterlife reeks strongly of crackpottery. It's the same with authors who think quantum physics has something interesting to say about consciousness.
I like how they're "authors" if they think Quantum Physics has something to do with consciousness. Not, say.. physicists. Like Henry Stapp, Richard Conn Henry, Bruce Rosenblum, Fred Kuttner, Roger Penrose, and quite a number of others.
The fact is, string theory, dark matter, and quantum physics in general offers one hell of a challenge to materialism. Precisely because it illustrates how many times, and in what ways, people (materialists in particular) have been wrong about "matter" itself. That's not direct support of an afterlife, but it's indirect support, namely by illustrating the problems of the one metaphysical position seen as most problematic for such scenarios.
And really, DL, you should talk. Most of what you state on philosophical subjects amounts to what janitors would have to clean up, if bulls used restrooms.
Even good physicists can be crackpots on certain subjects, especially when those subjects intersect with philosophy. Forgive me if I'm mistaken, but I don't think too many cognitive scientists or philosophers of mind take Penrose et al. very seriously on quantum mechanics and consciousness.
Materialism doesn't take a position on the kinds of matter there are. It's not a central tenet of materialism that all matter is composed of atoms or emits light. Furthermore, that we're not aware of all the kinds of matter there are doesn't make an afterlife even remotely plausible if we still have good reason to think that mental activity has a basis in ordinary matter. Or if we have no reason to expect the hitherto undiscovered forms of matter to be capable of furnishing consciousness. Again, I haven't read the book, so I may be missing something essential; but off-hand, D'Souza's point sounds as ridiculous as saying, "Physicists agree that we don't have a complete understanding of gravity. Therefore, we can't be so sure that Superman doesn't exist and fly around."
Sure, physicists can be crackpots. And so can philosophers and cognitive scientists, both in fields far murkier and given to quackery than the hard sciences. The fact is, there's quite a number of scientists (past and present, well-known and respected rather than esoteric nobodies) who think there's a link between consciousness and quantum physics, even if they disagree on the specifics (Stapp deeply disagrees with Penrose, for example.) I hope you've got better justification for writing them all off as crackpots other than "well, I don't see the philosophers talking about them much!"
As for materialism, if said metaphysic "doesn't take a position on the kinds of matter there are", then it's vacuous and can't mount an argument against dualism anyway, much less idealism or otherwise. And frankly, it often seems to be exactly that (see the SEP entry on how panpsychism is compatible with physicalism. How times change.)
What's more, the point doesn't just apply to exotic and theoretical types of matter (or whatever else the universe is 'made' of). It also illustrates that we have a lot to learn about "ordinary matter" itself. Bertrand Russell made a similar point re: matter, as have others. What D'Souza seems to be saying here is that it hardly helps to appeal to materialism as an argument against an afterlife when just what "matter" ("ordinary" or not) is, or just what nature is, is not only up in the air but has defied some long-standing expectations of ours. And, much as people may hate to admit it, D'Souza has a point.
I hope you've got better justification for writing them all off as crackpots other than "well, I don't see the philosophers talking about them much!"
Er, yeah. (1) There's no need for QM to explain anything in the mind. (2) What QM would do for the mind is not explained, or if it is, it relies on a particular interpretation of QM, which is a dodgy approach, since no interpretation is better than any other. (3) Quantum decoherence would destroy any quantum effects in brains at that their density and temperature.
This is why quantum consciousness folks are regarded as cranks and crackpots.
As for materialism, if said metaphysic "doesn't take a position on the kinds of matter there are", then it's vacuous and can't mount an argument against dualism anyway, much less idealism or otherwise.
Naturalism is about mechanisms. It's not a question of what kinds of stuff we're made of. In theory, we can imagine natural dualisms. That is, dualism in which aspects of consciousness are properly basic, but still subject to predictive laws. However, natural dualism is rejected by both materialists and theists, for different reasons. It's rejected by materialists because there's no evidence that there's more to minds than particle physics. It's rejected by theists because the implications of minds as mechanisms (whether physical or non-physical) scares the piss out of them.
No, D'Souza does not have a point. Nothing that D'Souza refers to changes the fact that matter is a naturalistic blend of determinism and randomness. Nothing to which he refers dispels causal closure of the physical. If you think it does, then, please, tell me how any quantum field theory could escape determinism + randomness. Add as many fields and dimensions as you want, and it ain't gonna happen.
It does come off sophomoric, something a stoner might say late on a Friday night. 'Dude, like, in string theory there are something like 12 dimensions. What if one of them is, like, the soul?'
I like that D'Souza carts out an old chestnut: minds have no mass; brains do have mass; therefore minds cannot be manifestations of brains.
What is the mass of digestion, or a heartbeat, or an action potential?
On the whole quantum brain issue, I've thought a bit more about this lately.
While quantum mechanics is needed to explain some biological phenomena (e.g., retinal transduction), these have always been low-level and quite localized phenomena.
The evidence suggests that consciousness is not such a low-level localized phenomenon (see this post). The evidence suggests that consciousness emerges as the result of interactions that involve multiple neurons (very likely in multiple areas of the brain). As DL suggested, maintaining coherence at such spatiotemporal scales, in a messy biological high-temperature environment, is something that has never been observed.
Also, we already have good models of how electrical events are generated in brains (electrical-conducatance based models of neuronal actvity). These models are quantitative, predictively fecund, and are the basis of modern neurophysiology (for some reason many in philosophy, cogsci, and other outside disciplines are unaware of this). They provide the most important class of models in modern neuroscience. People who talk about this issue, and are unaware of these models, are talking out of their butt.
At a lower-level, the electrical conductances in these models are explained in terms of the biophysics of single ion channels, so let's turn there briefly to see if they can help the quantophile.
Single ion channel function (and synaptic function) may require quantum mechanics for a full explanation. Let's assume for argument that they do, just to see how far it can get the quantophile.
Not very far, because these are highly localized processes: if quantum mechanics is needed to explain whether a single sodium ion goes through a sodium channel, that would not be surprising. Neither is it surprising that QM is needed to explain how individual photons are absorbed in the retina.
The problem is that there is no reason to associate such pipette-level phenomena with consciousness. I can study these ion channel properties in isolation in a single electrode, there is no reason to think these little molecules are conscious.
For that matter, your spinal cord is replete with such localized patch processes (synapses and ion channels). Is your spinal cord conscious? Is your retina conscious, because there are plenty of ion channels and synapses there too?
Stepping back a bit, this is not an a priori issue. If QM is important for higher-level brain function, this is something that must be demonstrated empirically, not established based on weird philosophy. For the quantophiles to be taken seriously, they need evidence that they are right. Where are the data?
My suggestion to the quantophiles is to take a model systems approach like a real biologist. Show that network-level effects are important in a set of cultured neurons, or in a simple model organism like C elegans or H medicinalis. These grand handwavy arguments will not work, especially given the evidence that they are simply wrong.
Sure, physicists can be crackpots. And so can philosophers and cognitive scientists, both in fields far murkier and given to quackery than the hard sciences. The fact is, there's quite a number of scientists (past and present, well-known and respected rather than esoteric nobodies) who think there's a link between consciousness and quantum physics, even if they disagree on the specifics (Stapp deeply disagrees with Penrose, for example.) I hope you've got better justification for writing them all off as crackpots other than "well, I don't see the philosophers talking about them much!" Maybe I should've originally said, "It's the same with authors who think quantum physics can be used to explain consciousness." I specifically had Penrose's writings in mind in my first comment.
As for materialism, if said metaphysic "doesn't take a position on the kinds of matter there are", then it's vacuous and can't mount an argument against dualism anyway, much less idealism or otherwise. And frankly, it often seems to be exactly that (see the SEP entry on how panpsychism is compatible with physicalism. How times change.)
Not true. Materialists re: mind maintain that mental facts are reducible to, or otherwise somehow "ontologically posterior" to, a bunch of non-physical facts. This requires that the components of the physical realizers of consciousness not be conscious themselves; but it says nothing about what any of their other properties are. Given this understanding, I would say that panpsychists are only materialists in a figurative sense.
What's more, the point doesn't just apply to exotic and theoretical types of matter (or whatever else the universe is 'made' of). It also illustrates that we have a lot to learn about "ordinary matter" itself. Bertrand Russell made a similar point re: matter, as have others. What D'Souza seems to be saying here is that it hardly helps to appeal to materialism as an argument against an afterlife when just what "matter" ("ordinary" or not) is, or just what nature is, is not only up in the air but has defied some long-standing expectations of ours. And, much as people may hate to admit it, D'Souza has a point.
Yeah, and you'll see a lot of this same reasoning echoed by the folks behind "What the Bleep Do We Know!?" when they talk about quantum channeling of ancient Atlantean spirits.
We certainly do have a lot to learn about ordinary matter: whether it's composed, for example, of vibrating strings in some higher-dimensional space. Again, though, none of the outstanding mysteries of string theory, let alone dark matter, appear to be pointing us toward anything remotely useful to D'Souza. Instead, they're pointing us toward more abstract, more mathematical and ultimately more "mechanistic" ways of understanding matter. Materialists don't need to prematurely appeal to some final theory of matter, as your comments suggest. They need only to argue for the trend of fundamental physical theories away from the mental. Therefore, it's hard for me to conceive of D'Souza as doing anything but offering an "afterlife of the gaps."
I haven't read the D'Souza but Blue Devil Knight sucked me into the discussion. I'm one of these 'quantophiles,' but I can stipulate that 'What the bleep' is not a serious source of argument about this issue.
My point of view is that the only way for a spatially distributed brain state that underlies consciousness to be causally effective AS A WHOLE, is for it to be a macroscopic quantum entangled state. I won't try to further explicate that argument here because BDK doesn't believe in 'armchair arguments.' However, I will point out that this argument does not depend on a particular interpretation of quantum mechanics--non-locality and genuine holism is implicit in quantum mechanics under (almost) any interpretation.
But I'll make a couple comments about why it's not actually impossible as most neuroscientists and physicists believe.
The primary objection to this idea is that the brain is hot and quantum coherence is not sustainable at brain temp. Quantophiles make a number of distinct arguments to dispute this point. Penrose and Hammeroff tend to talk about 'shielding,' which may be correct but is not very convincing. Stapp makes an argument similar to BDK's about the ion channels, but about the calcium ions that trigger exocytosis at synapses. He points out that the decision to release vesicles or not can be affected by the position of a few calcium ions. If synaptic transmission state can be in a superposition like this, then you quickly have a macroscopic entangled superposition of states because the synapse is deciding whether this signal will pass from one neuron to another.
But to me the real answer to the temperature objection is to note that that calculation (see e.g. Tegmark's) assumes thermodynamic equilibrium. In fact the brain is in a steady state with energy being pumped through it, and such NON-equilibrium systems are known (e.g. Prigogine) to generate stable order that is resistant to perturbation. In fact Frohlich modeled living tissue as a 'bag of electric dipoles' and found that above a threshold amount of energy flow, these dipoles condense into a coherent vibrational state--at high temperatures.
Consistent with that picture, living tissue does in fact emit weak coherent light, known as biophotons (e.g. Popp). I'm not making this up, and this is experimental evidence.
Another thing I wanted to comment on is the characterization of quantum dynamics as determinism plus randomness. There is a widespread tendency to write off quantum mechanics as merely adding 'randomness' to physics, but I think what it really adds is a genuine holism. The randomness is in some sense derivable from the holism (because local observables are influenced by distant unmeasured variables) whereas the holism is not derivable from the randomness.
As an example, consider a superconductor. If you try to describe the material as a bunch of electrons and protons, you will never derive the superconductive behavior. But if you recognize that the electrons have condensed into bound 'Cooper pairs,' and describe the material in those terms, you can derive the magical current flow without resistance. If quantum dynamics were merely about randomness in the behavior of the electrons, they would never manifest such unbelievable coordination.
I'm not saying there are superconductors in the brain. I'm just saying that (a) a macroscopic quantum brain state is not impossible as some maintain, and (b) that need not add only randomness; it could add coordination.
Just one more point. Another major criticism of the quantum brain idea is that we already know how neurons work and we have explained a lot with them, so the question is what is left for this putative quantum state to do, and how could it influence the behavior of neurons? As is well known, synaptic transmission is very fallible and stochastic. If a hypothetical quantum brain state involves the cytoskeleton or ion channels (for example) then it could influence these synaptic transmission probabilities in a number of ways. If it can moreover coordinate transmission at many synapses, there is your functional interface between the quantum state and the dynamics of neurons--and this would be very difficult to detect with present experimental technology (although imaging of individual transmission events is just barely feasible now).
Mike: that all seems interesting. I would be surprised if QM effects weren't important at individual synapses or ion channels, perhaps even influencing release probability at a synapse (release probability is probability that you will get neurotransmitter release at a synapse in response to an action potential in a neuron).
The big issue is how you get from such micropipette-level quantum phenomena to larger-scale things in a real brain. You address this some, but it seems mostly to be blocking others arguments that it isn't possible, so you (for the time being) establish it is a logical possibility. That is a far cry from establishing it as plausible, or providing positive evidence.
That's pretty much where I stand for the time being: it's a remote logical possibility. It is ultimately an empirical question. Hence, it deserves 0.001% of funding in consciousness research. :)
D'Souza offers an ad ignorantium typical of fundamentalists (Ed Von Feser does it as well):
Scientific materialism can't explain all the workings of the human mind (intention, memory, language, higher order thinking, etc), according to the believer. Ergo, Mind exists apart from nature, and souls exist, afterlife, etc. Now upgraded with mystico readings of the copenhagen interpretation of QM (and Bohr reportedly was no mystic or metaphysical dualist), which had nothing to do with the neurology of the brain.
Mike: I'm glad you mentioned that Stapp article (ref below). You might know the answer to my confusion.
In the paper, they say: "The narrowness of the channel restricts the lateral spatial dimension. Consequently, the lateral velocity is forced by the quantum uncertainty principle to become large. This causes the quantum cloud of possibilities associated with the calcium ion to fan out over an increasing area as it moves away from the tiny channel to the target region where the ion will be absorbed as a whole, or not absorbed at all, on some small triggering site."
Mike, is it OK to draw these conclusions without doing the calculations based on the actual mechanism of ion transport across the channel and ion diffusion in the cell?
That is, should what they say be treated as something that follows obviously from QM, or is it a hypothesis about what QM would predict, something that would need to be verified based on the details of the mechanisms involved?
For those curious, the paper is: Schwartz, JM; Stapp, HP; Beauregard, M (2005) Quantum physics in neuroscience and psychology: a neurophysical model of mind-brain interaction Philosophical Transactions of the Royal Society: B Series, 360, 1309-1327.
16 comments:
I like his analogy of apologetics as janitorial work, clearing the debris.
Yes, I suspect that janitorial work is indeed D'Souza's true calling.
Haven't read the book, but pointing to string theory and dark matter as evidence for an afterlife reeks strongly of crackpottery. It's the same with authors who think quantum physics has something interesting to say about consciousness.
I like how they're "authors" if they think Quantum Physics has something to do with consciousness. Not, say.. physicists. Like Henry Stapp, Richard Conn Henry, Bruce Rosenblum, Fred Kuttner, Roger Penrose, and quite a number of others.
The fact is, string theory, dark matter, and quantum physics in general offers one hell of a challenge to materialism. Precisely because it illustrates how many times, and in what ways, people (materialists in particular) have been wrong about "matter" itself. That's not direct support of an afterlife, but it's indirect support, namely by illustrating the problems of the one metaphysical position seen as most problematic for such scenarios.
And really, DL, you should talk. Most of what you state on philosophical subjects amounts to what janitors would have to clean up, if bulls used restrooms.
Even good physicists can be crackpots on certain subjects, especially when those subjects intersect with philosophy. Forgive me if I'm mistaken, but I don't think too many cognitive scientists or philosophers of mind take Penrose et al. very seriously on quantum mechanics and consciousness.
Materialism doesn't take a position on the kinds of matter there are. It's not a central tenet of materialism that all matter is composed of atoms or emits light. Furthermore, that we're not aware of all the kinds of matter there are doesn't make an afterlife even remotely plausible if we still have good reason to think that mental activity has a basis in ordinary matter. Or if we have no reason to expect the hitherto undiscovered forms of matter to be capable of furnishing consciousness. Again, I haven't read the book, so I may be missing something essential; but off-hand, D'Souza's point sounds as ridiculous as saying, "Physicists agree that we don't have a complete understanding of gravity. Therefore, we can't be so sure that Superman doesn't exist and fly around."
Sure, physicists can be crackpots. And so can philosophers and cognitive scientists, both in fields far murkier and given to quackery than the hard sciences. The fact is, there's quite a number of scientists (past and present, well-known and respected rather than esoteric nobodies) who think there's a link between consciousness and quantum physics, even if they disagree on the specifics (Stapp deeply disagrees with Penrose, for example.) I hope you've got better justification for writing them all off as crackpots other than "well, I don't see the philosophers talking about them much!"
As for materialism, if said metaphysic "doesn't take a position on the kinds of matter there are", then it's vacuous and can't mount an argument against dualism anyway, much less idealism or otherwise. And frankly, it often seems to be exactly that (see the SEP entry on how panpsychism is compatible with physicalism. How times change.)
What's more, the point doesn't just apply to exotic and theoretical types of matter (or whatever else the universe is 'made' of). It also illustrates that we have a lot to learn about "ordinary matter" itself. Bertrand Russell made a similar point re: matter, as have others. What D'Souza seems to be saying here is that it hardly helps to appeal to materialism as an argument against an afterlife when just what "matter" ("ordinary" or not) is, or just what nature is, is not only up in the air but has defied some long-standing expectations of ours. And, much as people may hate to admit it, D'Souza has a point.
Anonymous,
I hope you've got better justification for writing them all off as crackpots other than "well, I don't see the philosophers talking about them much!"
Er, yeah. (1) There's no need for QM to explain anything in the mind. (2) What QM would do for the mind is not explained, or if it is, it relies on a particular interpretation of QM, which is a dodgy approach, since no interpretation is better than any other. (3) Quantum decoherence would destroy any quantum effects in brains at that their density and temperature.
This is why quantum consciousness folks are regarded as cranks and crackpots.
As for materialism, if said metaphysic "doesn't take a position on the kinds of matter there are", then it's vacuous and can't mount an argument against dualism anyway, much less idealism or otherwise.
Naturalism is about mechanisms. It's not a question of what kinds of stuff we're made of. In theory, we can imagine natural dualisms. That is, dualism in which aspects of consciousness are properly basic, but still subject to predictive laws. However, natural dualism is rejected by both materialists and theists, for different reasons. It's rejected by materialists because there's no evidence that there's more to minds than particle physics. It's rejected by theists because the implications of minds as mechanisms (whether physical or non-physical) scares the piss out of them.
No, D'Souza does not have a point. Nothing that D'Souza refers to changes the fact that matter is a naturalistic blend of determinism and randomness. Nothing to which he refers dispels causal closure of the physical. If you think it does, then, please, tell me how any quantum field theory could escape determinism + randomness. Add as many fields and dimensions as you want, and it ain't gonna happen.
It does come off sophomoric, something a stoner might say late on a Friday night. 'Dude, like, in string theory there are something like 12 dimensions. What if one of them is, like, the soul?'
I like that D'Souza carts out an old chestnut:
minds have no mass;
brains do have mass;
therefore minds cannot be manifestations of brains.
What is the mass of digestion, or a heartbeat, or an action potential?
On the whole quantum brain issue, I've thought a bit more about this lately.
While quantum mechanics is needed to explain some biological phenomena (e.g., retinal transduction), these have always been low-level and quite localized phenomena.
The evidence suggests that consciousness is not such a low-level localized phenomenon (see this post). The evidence suggests that consciousness emerges as the result of interactions that involve multiple neurons (very likely in multiple areas of the brain). As DL suggested, maintaining coherence at such spatiotemporal scales, in a messy biological high-temperature environment, is something that has never been observed.
Also, we already have good models of how electrical events are generated in brains (electrical-conducatance based models of neuronal actvity). These models are quantitative, predictively fecund, and are the basis of modern neurophysiology (for some reason many in philosophy, cogsci, and other outside disciplines are unaware of this). They provide the most important class of models in modern neuroscience. People who talk about this issue, and are unaware of these models, are talking out of their butt.
At a lower-level, the electrical conductances in these models are explained in terms of the biophysics of single ion channels, so let's turn there briefly to see if they can help the quantophile.
Single ion channel function (and synaptic function) may require quantum mechanics for a full explanation. Let's assume for argument that they do, just to see how far it can get the quantophile.
Not very far, because these are highly localized processes: if quantum mechanics is needed to explain whether a single sodium ion goes through a sodium channel, that would not be surprising. Neither is it surprising that QM is needed to explain how individual photons are absorbed in the retina.
The problem is that there is no reason to associate such pipette-level phenomena with consciousness. I can study these ion channel properties in isolation in a single electrode, there is no reason to think these little molecules are conscious.
For that matter, your spinal cord is replete with such localized patch processes (synapses and ion channels). Is your spinal cord conscious? Is your retina conscious, because there are plenty of ion channels and synapses there too?
Stepping back a bit, this is not an a priori issue. If QM is important for higher-level brain function, this is something that must be demonstrated empirically, not established based on weird philosophy. For the quantophiles to be taken seriously, they need evidence that they are right. Where are the data?
My suggestion to the quantophiles is to take a model systems approach like a real biologist. Show that network-level effects are important in a set of cultured neurons, or in a simple model organism like C elegans or H medicinalis. These grand handwavy arguments will not work, especially given the evidence that they are simply wrong.
Sure, physicists can be crackpots. And so can philosophers and cognitive scientists, both in fields far murkier and given to quackery than the hard sciences. The fact is, there's quite a number of scientists (past and present, well-known and respected rather than esoteric nobodies) who think there's a link between consciousness and quantum physics, even if they disagree on the specifics (Stapp deeply disagrees with Penrose, for example.) I hope you've got better justification for writing them all off as crackpots other than "well, I don't see the philosophers talking about them much!"
Maybe I should've originally said, "It's the same with authors who think quantum physics can be used to explain consciousness." I specifically had Penrose's writings in mind in my first comment.
As for materialism, if said metaphysic "doesn't take a position on the kinds of matter there are", then it's vacuous and can't mount an argument against dualism anyway, much less idealism or otherwise. And frankly, it often seems to be exactly that (see the SEP entry on how panpsychism is compatible with physicalism. How times change.)
Not true. Materialists re: mind maintain that mental facts are reducible to, or otherwise somehow "ontologically posterior" to, a bunch of non-physical facts. This requires that the components of the physical realizers of consciousness not be conscious themselves; but it says nothing about what any of their other properties are. Given this understanding, I would say that panpsychists are only materialists in a figurative sense.
What's more, the point doesn't just apply to exotic and theoretical types of matter (or whatever else the universe is 'made' of). It also illustrates that we have a lot to learn about "ordinary matter" itself. Bertrand Russell made a similar point re: matter, as have others. What D'Souza seems to be saying here is that it hardly helps to appeal to materialism as an argument against an afterlife when just what "matter" ("ordinary" or not) is, or just what nature is, is not only up in the air but has defied some long-standing expectations of ours. And, much as people may hate to admit it, D'Souza has a point.
Yeah, and you'll see a lot of this same reasoning echoed by the folks behind "What the Bleep Do We Know!?" when they talk about quantum channeling of ancient Atlantean spirits.
We certainly do have a lot to learn about ordinary matter: whether it's composed, for example, of vibrating strings in some higher-dimensional space. Again, though, none of the outstanding mysteries of string theory, let alone dark matter, appear to be pointing us toward anything remotely useful to D'Souza. Instead, they're pointing us toward more abstract, more mathematical and ultimately more "mechanistic" ways of understanding matter. Materialists don't need to prematurely appeal to some final theory of matter, as your comments suggest. They need only to argue for the trend of fundamental physical theories away from the mental. Therefore, it's hard for me to conceive of D'Souza as doing anything but offering an "afterlife of the gaps."
Hi all,
I haven't read the D'Souza but Blue Devil Knight sucked me into the discussion. I'm one of these 'quantophiles,' but I can stipulate that 'What the bleep' is not a serious source of argument about this issue.
My point of view is that the only way for a spatially distributed brain state that underlies consciousness to be causally effective AS A WHOLE, is for it to be a macroscopic quantum entangled state. I won't try to further explicate that argument here because BDK doesn't believe in 'armchair arguments.' However, I will point out that this argument does not depend on a particular interpretation of quantum mechanics--non-locality and genuine holism is implicit in quantum mechanics under (almost) any interpretation.
But I'll make a couple comments about why it's not actually impossible as most neuroscientists and physicists believe.
The primary objection to this idea is that the brain is hot and quantum coherence is not sustainable at brain temp. Quantophiles make a number of distinct arguments to dispute this point. Penrose and Hammeroff tend to talk about 'shielding,' which may be correct but is not very convincing. Stapp makes an argument similar to BDK's about the ion channels, but about the calcium ions that trigger exocytosis at synapses. He points out that the decision to release vesicles or not can be affected by the position of a few calcium ions. If synaptic transmission state can be in a superposition like this, then you quickly have a macroscopic entangled superposition of states because the synapse is deciding whether this signal will pass from one neuron to another.
But to me the real answer to the temperature objection is to note that that calculation (see e.g. Tegmark's) assumes thermodynamic equilibrium. In fact the brain is in a steady state with energy being pumped through it, and such NON-equilibrium systems are known (e.g. Prigogine) to generate stable order that is resistant to perturbation. In fact Frohlich modeled living tissue as a 'bag of electric dipoles' and found that above a threshold amount of energy flow, these dipoles condense into a coherent vibrational state--at high temperatures.
Consistent with that picture, living tissue does in fact emit weak coherent light, known as biophotons (e.g. Popp). I'm not making this up, and this is experimental evidence.
Another thing I wanted to comment on is the characterization of quantum dynamics as determinism plus randomness. There is a widespread tendency to write off quantum mechanics as merely adding 'randomness' to physics, but I think what it really adds is a genuine holism. The randomness is in some sense derivable from the holism (because local observables are influenced by distant unmeasured variables) whereas the holism is not derivable from the randomness.
As an example, consider a superconductor. If you try to describe the material as a bunch of electrons and protons, you will never derive the superconductive behavior. But if you recognize that the electrons have condensed into bound 'Cooper pairs,' and describe the material in those terms, you can derive the magical current flow without resistance. If quantum dynamics were merely about randomness in the behavior of the electrons, they would never manifest such unbelievable coordination.
I'm not saying there are superconductors in the brain. I'm just saying that (a) a macroscopic quantum brain state is not impossible as some maintain, and (b) that need not add only randomness; it could add coordination.
Just one more point. Another major criticism of the quantum brain idea is that we already know how neurons work and we have explained a lot with them, so the question is what is left for this putative quantum state to do, and how could it influence the behavior of neurons? As is well known, synaptic transmission is very fallible and stochastic. If a hypothetical quantum brain state involves the cytoskeleton or ion channels (for example) then it could influence these synaptic transmission probabilities in a number of ways. If it can moreover coordinate transmission at many synapses, there is your functional interface between the quantum state and the dynamics of neurons--and this would be very difficult to detect with present experimental technology (although imaging of individual transmission events is just barely feasible now).
Peace!
Mike: that all seems interesting. I would be surprised if QM effects weren't important at individual synapses or ion channels, perhaps even influencing release probability at a synapse (release probability is probability that you will get neurotransmitter release at a synapse in response to an action potential in a neuron).
The big issue is how you get from such micropipette-level quantum phenomena to larger-scale things in a real brain. You address this some, but it seems mostly to be blocking others arguments that it isn't possible, so you (for the time being) establish it is a logical possibility. That is a far cry from establishing it as plausible, or providing positive evidence.
That's pretty much where I stand for the time being: it's a remote logical possibility. It is ultimately an empirical question. Hence, it deserves 0.001% of funding in consciousness research. :)
D'Souza offers an ad ignorantium typical of fundamentalists (Ed Von Feser does it as well):
Scientific materialism can't explain all the workings of the human mind (intention, memory, language, higher order thinking, etc), according to the believer. Ergo, Mind exists apart from nature, and souls exist, afterlife, etc. Now upgraded with mystico readings of the copenhagen interpretation of QM (and Bohr reportedly was no mystic or metaphysical dualist), which had nothing to do with the neurology of the brain.
Mike:
I'm glad you mentioned that Stapp article (ref below). You might know the answer to my confusion.
In the paper, they say:
"The narrowness of the channel restricts the lateral spatial dimension. Consequently, the lateral velocity is forced by the quantum uncertainty principle to become large. This causes the quantum cloud of possibilities associated with the calcium ion to fan out over an increasing area as it moves away from the tiny channel to the target region where the ion will be absorbed as a whole, or not absorbed at all, on some small triggering site."
Mike, is it OK to draw these conclusions without doing the calculations based on the actual mechanism of ion transport across the channel and ion diffusion in the cell?
That is, should what they say be treated as something that follows obviously from QM, or is it a hypothesis about what QM would predict, something that would need to be verified based on the details of the mechanisms involved?
For those curious, the paper is:
Schwartz, JM; Stapp, HP; Beauregard, M (2005) Quantum physics in neuroscience and psychology: a neurophysical model of mind-brain interaction Philosophical Transactions of the Royal Society: B Series, 360, 1309-1327.
The following seems like what I was imagining, concrete predictions based on mechanism of ion channel function.
Roy S, Llinás R. C R Biol. 2009 Jun;332(6):517-22. .Relevance of quantum mechanics on some aspects of ion channel function.
I'm not qualified to judge this paper, because it's basically a physics paper, but it seems interesting.
Link here.
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