Wednesday, April 20, 2011

Quantum "Mind" isn't the same as Quantum function!

Astoundingly, at a recent conference convened at The Philotetes Center, physicist Mark Alford attempted to rebut Deepak Chopra's claim of a "quantum mind" (i.e. one unified mind field on the basis of quantum nonlocality) by arguing no quantum mechanics (QM) is needed to parse brain function. Of course, he is quite wrong (not on the "quantum mind" aspect) since one can find numerous ways QM enters if one gives even a little thought to it.

Alford remarked (see e.g. Skeptical Inquirer, May-June, p. 8) that:

"It seems improbable that these very delicate processes are the crucial feature in the functioning of the human brain which is not a suitagle environment for quantum subtlety".

But in fact, he is quite mistaken. For example, we know that the scale of the synaptic cleft is on the order of 200-300 nm and hence subject to the Heisenberg Uncertainty Principle. This is precisely a quantum scale so it makes sense that the Heisenberg Principle would apply at this level, and one can therefore surmise all the mutual interference effects that are attendant. Technically, the Heisenberg Principle is the embodiment of wave-particle ambiguity at those scales < 300nm and is thus a reflection of the Principle of Complementarity in Quantum physics. It is usually expressed via the Poisson brackets (with non-commuting variables x= position, p = momentum, in 1D):

[x, p] = -i h/ 2 π

where h is the Planck constant of action.

If two variables a, b commute, then one has:

[a, b] = (a*b - b*a) = 0

if not, then:

[a,b] = (a*b - b*a) = -1

and we say a and b are 'non-commuting'.

(You may observe one aspect at any one time, but not the other).

In term's of Bohr's (Complementarity) Principle, the variables x (position) and p(momentum) are regarded as "mutually interfering observables". In terms of brain function it would mean that those electrons configured into brain dynamics can exhibit wave-particle complementarity in the course of neural transmissions which always entail electrical signal transmissions. Of course, if Heisenberg's principle didn't apply - meaning we could know both the position and momentum to the same degree of accuracy then:

[x, p] = 0

Is this really the case? Physicist Henry Stapp (Mind, Matter and Quantum Mechanics) has shown that application of the Heisenberg Uncertainty Principle to Ca+2 ions (involved in neural transmissions at body temperature) discloses the associated wave packet dimension increases to many times the size of the ion itself. This means that any actual measurements made will certainly show a non-zero result for the Poisson bracket computation. Thus we can represent the ion uptake superposition as a separate contributing wave function, viz.:

U (A1....An) + U (Ca+2)n

where the A1.....An designate different neuronal complexes. (See e.g., Stapp, ibid.)

Beyond this example, we know that the vast information capacity of the typical human brain is more readily explained by appeal to quantum bits, "qubits" rather than ordinary bits. With qubits, with qubits one has the superposition of a combined data element (1 + 0) which implies: U = U(1) + U(0).In general, for any given n-bit combination – with n a whole number, a qubit register can accommodate 2 to the nth power total combinations at one time. Thus, 16 combinations could be held in memory for 4-bits, 32 for 5-bits, and so on. This change marks an exponential (two to the n, or 2^n) increase over any classical counterpart. Since, human brains typically can hold the equivalent in memory of whole libraries, it seems that qubit processing is at least worth consideration and is certainly not "improbable".

Alford is quoted as also asserting (SI, ibid.):

"It's more likely that consciousness arises from other, more conventional bits of science, and you don't need to reach all the way to this, the most exotic, the most delicate, the most bizarre bit of modern physics."

And yet, despite being "bizarre", this "exotic bit of physics" (understatement if ever there was one) has reshaped our entire modern scientific and technological landscape! It's given us high powered lasers and also enables us to put solid state electronics to practical use employing something called "quantum tunneling" - whereby a lower energy wave can penetrate a higher energy barrier, as well as explaining why solar fusion only occurs about once every 14 billion years in the Sun's core. It has also enabled us to probe the inside of the atom and atomic transition processes, including being able to associates discrete energy levels with atomic states! Hence, it is nowhere near the abstruse, incomprehensible theory that Alford claims.

His argument that we don't need to go that far" is also somewhat puzzling. Why not, if it can be shown to work (see e.g. David Bohm's example in his book, Quantum Theory, pp. 168-69)? His argument is analagous to asserting we don't need to go all the way to use differential calculus to compute rocket trajectories! That the latter is "way too exotic" and "delicate"! Well, true! One could rely on just algebra to attend to rocket flight(with finite differences substituted for where differentials appear) and come away with at least some basic info. But it'd be much cruder than what the dy/dt's would yield, and you might not be able to land on Mars - even after ten years of computations!

His other remark is also rather disappointing for a physicist:

"If you rely too much on the current scientific paradigm, wait a hundred years- it's been replaced. So I don't think you want to be using quantum mechanics as a foundation. You can use it as inspiration...but I don't think you want to actually build on it.."

Here he conflates scientific paradigm with scientific theory (e.g. Quantum theory). The two are not one and the same. The current paradigm, if one needs to articulate it, is more accurately a form of reductionist mechanism. That it, no emergent properties are presumed to issue from basic material interactions or processes. In this sense, Alford and his cohort who subscribe to it are the ones on less than firm scientific grounds, since we know paradigms do shift. (See Thomas Kuhn's work on the 'Structure of Scientific Revolutions') Thus, in a hundred years, the reductionist mechanical model may be totally replaced by an emergent or "holistic" model, say of the type proposed by the late physicist David Bohm in his Wholeness and the Implicate Order(Routledge & Kegan Paul, 1980).

Further, Alford is mistaken in how he portrays the fate of theories. Theories, real ones which start out with solid evidence and predictions, are seldom if ever "replaced". For a quick example, look at Newtonian Mechanics. Did we replace it with the advent of Quantum Mechanics? Not at all! It remains a valid theory to apply, say to launch an artificial satellite into Earth orbit, or to put a Rover on Mars. It has not been "replaced" and indeed, in the standard Schrodinger equation, quantum mechanics is found to revert to Newtonian mechanics in the limit of very lare principal quantum number (n -> oo).

Another reason why quantum mechanics can't be conflated with the current paradigm, is because it is only one of two props for modern physics, the other being relativity (special and general theories). I note that Alford has said nothing on those, though granted Chopra didn't incorporate them into his "quantum mind" either. However, if one is going to make referene to "the current scientific paradigm", one is at least obligated to include relativity as part of it!

Now, it was physicist David Bohm who first pointed out (op. cit., p. 169), the very precise analogy of quantum processes to thought. In particular, the quantum "wave packet collapse" (e.g. to a single eigenstate, from a superposition of eigenstates) is exactly analogous to the phenomenon of trying to pinpoint what one is thinking about at the instant he is doing such thinking. More often than not, when one does this, as Bohm notes: "uncontrollable and unpredictable changes" are introduced into the thought process or train.

Recall as I noted from earlier blogs (See: 'A Material Model of Consciousness', Parts I-III), that Bohm also provided a putative basis for a "quantum mind" which he referred to as the Holomovement. This was done by positing a hyper-dimensional reality (e.g. 5- dimensional) in which mind was enfolded as part of an "implicate order". To enable a unified mental field within this higher dimensionality, Bohm appealed to "hidden variables" obeying Heisenberg relations such that:

(delta p)(delta q) > h/ 2π

where p, q denote two hidden variables underlying a sub-quantal scale uncertainty relation. From this (leaving out lots of details) he developed an agent to assist in the nonlocal action of distal variables, and called it the "quantum potential", defined:

V_Q = h(f' - f), where h is Planck's constant.

Thus, V_Q has units of energy. On average, the greater the number of possible states, the greater the difference (f' - f) and the greater the quantum potential.(See, e.g. the illustration of the computation for such a potential for a pair of Gaussian slits, from Bohm, D. and Hiley, B.J.: Foundations of Physics, Vol. 12, No. 10, p. 1001)In general, V_Q= {- ħ^2/ 2m} [grad R]^2 / R for a wave function, U = R exp(iS/ħ) where R,S are real.

While all this looks fascinating, even Bohm admitted the plausible acceptance of his conjecture rested on the outcome of a particular experiment. The experiment he proposed was actually designed by Rapisarda and Gozzini and became known as the "Gozzini experiment". It was originally to be conducted near Pisa, Italy ca. 1995. Alas, up to now - so far as I know- it hasn't been carried out. But if it had, and real de Broglie waves had been detected then this would be at least an indirect basis for Bohm's claim, as well as a feather in the hat for the claim of "quantum mind". Without it, we have no valid basis to assert such a claim, and can only adopt Bohm's vision as "inspiration".

Bottom line on Alford's take: He was correct is rejecting Chopra's "quantum mind" but used the wrong reasons, which amounted to tossing out the baby (quantum mechanics) with the bathwater (quantum mind + QM). If he had refined his arguments a bit more and had more knowledge of the background issues, in particular on Bohm's work, he could have quashed Chopra's claims without having to resort to nullification of QM in brain processes as well!

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