There are some people who drop the words “quantum mechanics” into almost all scientific and philosophical conversations. More relevantly, the words (to cite just two examples) “quantum dualism” (i.e., in the Cartesian — not Niels Bohr’s complementarity — sense) and “quantum coherence” also feature strongly in debates about consciousness.
Quantum physics is sexy and exotic. It’s also counter-intuitive. Hence the appeal.
Quantum mechanics is so sexy that it even explains free will and, therefore, mind-body dualism. Or at least the Australian neurophysiologist and philosopher John Eccles (who won the Noble Prize in 1963) believed so. In concrete terms, Eccles (who died in 1997 — a year or so after Horgan’s interview) claimed that the mind (or self) must
“exert its influence over the brain by ‘deciding’ which neuron will fire and which will not”.
Yet, despite all that neuroscience (or physical theory), John Eccles still conceded: “We have no proof of any of this.” So perhaps what was truly motivating Eccles (as John Horgan suggests) is his aversion to what he called “cheap materialism”. Indeed Eccles classed himself as a “religious person”. Moreover, he added:
“[T]he very nature of the mind is the same as the nature of life. It’s a divine creation.”
So whereas as Eccles believed that quantum mechanics explains free will, so the mathematical physicist Roger Penrose believes that it explains consciousness itself. In fact the two theories tie together (if in a fairly vague way).
For Eccles, quantum indeterminism (or, in his case, the superposition of physical states at the synapses of a neurone) is explained by the “action” of the self or mind. With Penrose, the self is kept out of the picture; though quantum indeterminism is kept in. More specifically:
“Penrose conjectured that microtubules perform non-deterministic, quasi-quantum computations that somehow give rise to consciousness.”
But what of the scientific sceptics who play down quantum mechanics — at least when it comes to consciousness and mind? John Horgan had this to say on the matter:
“There is one issue on which Crick, Edelman, and indeed almost all neuroscientists agree: the properties of the mind do not depend in any crucial way on quantum mechanics.”
Note here that it’s neuroscientists who “agree” on this; not philosophers, psychologists, physicists and others. Yet it’s neuroscientists who prod and probe into the the brain. So, at least on the surface, it would seem that it’s neuroscientists who should know what they’re talking about. Sure, philosophical and conceptual issues will impinge on what they claim; though surely they’re the best people to ask when it come to this question:
Do the mind and consciousness depend in any crucial way on quantum mechanics?
So how could, say, a philosopher or a psychologist answer that question?
Yet the obvious point here is that neuroscientists don’t prod and probe at the quantum level. Indeed many (i.e., not all!) neuroscientists may be more or less illiterate when it comes to quantum mechanics. So no wonder many of them ignore the facts and realities of quantum mechanics; or, at the very least, play them down.
“some neural equivalent of Heisenberg’s uncertainty principle might restrict our ability to trace the brain’s activity in minute detail”.
Sure; that was a very minor admission from Crick.
In a certain — even in a strong — sense it’s certainly the case that the brain itself (if not consciousness) does depend on quantum mechanics. Yet that’s simply because every physical object and physical event depends on quantum mechanics. That is, the micro-constituents of all physical objects and events are ultimately made up of particles, forces and fields that have no meaning outside of the theoretical ambit of quantum mechanics.
So this is a good place to take a look at Daniel Dennett’s quantum car.
Daniel Dennett’s Quantum Car
“Most biologists think that quantum effects all just cancel out in the brain, that there’s no reason to think they’re harnessed in any way. Of course they’re there; quantum effects are there in your car, your watch, and your computer. But most things — most macroscopic objects — are, as it were, oblivious to quantum effects. They don’t amplify them; they don’t hinge on them. Roger [Penrose] thinks that the brain somehow exploits quantum effects.”
In other words:
Sure; there are quantum happenings in the brain as a whole or in neurons. Then again, there are quantum happenings in your car, watch and television.
It may be true that in order for Dennett’s car to be a car, it doesn’t depend on the quantum effects which are occurring inside it. However, why should that also be true of the brain and its relation to mind or to consciousness? The nature and functioning of a car (or watch) is very different to the reality and functioning of the brain and its relation to consciousness. A car is (to use Dennett’s word) “oblivious” to the quantum effects inside — though only if it is treated qua car! However, it’s of course the case that a car can also be analysed as a medium of quantum effects; though not, again, qua car.
Then again, it is strictly true that a car — even qua car — doesn’t depend on quantum effects/events/conditions? Surely it does so in the simple sense that if there were no quantum effects/events/conditions, then there would be no car either. And, yes, it’s true that this also applies to literally all other physical objects — including biological and artificial objects.
Of course we’ll now need to know exactly why “quantum effects” don’t transfer to the brain as a whole. Alternatively, why aren’t quantum effects (to use Dennett’s words) “amplified” and “exploited” by the brain? More specifically, we’ll need to know why such things don’t cause (or bring about) mental phenomena or consciousness. In other words:
Why is there such a sharp dividing line between Dennett’s quantum effects in the brain (or in neurons) and consciousness itself?
Surely there can’t be such a neat and tiny cut-off point (an — as it were - Heisenberg cut) between these two worlds. Then again, it’s not logically absurd to argue that there is indeed such a clear cut-off point.
Large-Scale Quantum Effects
Yet, despite all the above, the mathematical physicist Roger Penrose argues (as do many biologists and physicists) that quantum effects/events/conditions do indeed have an effect on the large scale. He makes that point plain in the following passage:
“The very existence of solid bodies, the strengths and physical properties of materials, the nature of chemistry, the colours of substances, the phenomena of freezing and boiling, the reliability of inheritance — these, and many other familiar properties, require the quantum theory for their explanations.”
It can now be argued that even though these “solid bodies” and “materials” do “require the quantum theory for their explanations”; that doesn’t also automatically mean that such quantum effects are in any way substantive. It simply means that quantum mechanics is a part of the whole picture (as in the case of Dennett’s car). So, in the sense of supplying a complete picture of such bodies and materials — then, yes, of course quantum theory will be required.
Yet Dennett himself does accept that quantum events/effects/conditions/etc. influence (or affect) the large scale. For example, he says that quantum mechanics is
“stunningly successful at predicting and explaining many phenomena, including everyday phenomena such as the reflection and refraction of lights, and the operation of the proteins in our retinas that permit us to see”.
Of course it may still be the case that because
quantum mechanics can (to use Penrose’s words) “predict and explain” such things as (to use Dennett’s words) “the reflection and refraction of lights”
that this doesn’t also mean that
quantum mechanics fully accounts for these things.
…. Then again, surely it does mean that!
And if all this is true of the aforementioned light and protein molecules, then why can’t it also be true of the brain and consciousness? Of course the parallels between
quantum mechanics and the reflection and refraction of light
quantum mechanics and the brain's relation to the mind (or consciousness)
may not be parallel (or equivalent) in every respect. However, surely that wouldn’t matter too much in this case. What matters is whether or not quantum mechanics is having an impact on the brain and therefore on the mind (or consciousness). It doesn’t need to be the case that quantum mechanics does so in precisely the same way in which it impacts on (to use Penrose’s words again)
“solid bodies, the strengths and physical properties of materials, the nature of chemistry, the colours of substances, the phenomena of freezing and boiling, the reliability of inheritance”.
To repeat: perhaps the quantum-mechanical explanations of these phenomena are at a different level to actually arguing that quantum-mechanical events actually bring about, cause or even constitute such phenomena. Again, is there a difference between
quantum mechanics being part of the explanation of consciousness (i.e., because quantum happenings occur within neurons, etc.)
quantum-mechanical effects/events/states bringing about or constituting consciousness
Surely if quantum mechanics can explain consciousness, then it may be because quantum-mechanical events/effects/conditions also bring about or actually constitute consciousness.
Conclusion: The Sexy Mystery of Consciousness
Kurt Gödel’s theorems are a helpful way to sum things up here.
Gödel’s theorems are also sexy. They’re applied to domains to which they shouldn’t (it can be argued) be applied. That is, theorems which were originally and primarily about mathematical systems are now applied left, right and centre. Nonetheless, since physics depends so heavily on mathematics, then perhaps there is something to the many connections which are made between Gödel’s theorems and everything else under the sun.
As for the sex appeal of quantum mechanics itself, John Horgan writes:
“[Francis] Crick’s partner Christof Koch summed up the quantum-consciousness thesis in a syllogism: Quantum mechanics is mysterious, and consciousness is mysterious. Q.E.D.: quantum mechanics and consciousness must be related.”
More specifically, the obvious question is:
Why do (or would) non-determinism (or acausality), quantum computations, quantum coherence, etc. give rise to consciousness and the “what it is like” to, say, smell a rose?
Is it this argument again? -
i) Consciousness is mysterious. ii) Quantum mechanics is mysterious. iii) Therefore consciousness and quantum mechanics simply must be related.
Could it be that some people believe the above simply because there are no other conclusive answers at present? Thus do they also believe this must be answer? Yet if that were the case, then many other outrageous — or simply radical — things may be the answer too. So why is this quantum stuff more feasible than (as the philosopher Patricia Churchland put it) “pixie dust in the synapses” when it comes to explaining consciousness?
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