Tuesday, February 8, 2011

Roundtable on quantum mind

Excerpt from this link:

The salon was held at the Philoctetes Center for the Multidisciplinary Study of the Imagination....a roundtable about the quantum mind, the theory that quantum mechanical phenomena, such as quantum entanglement and superposition, may form the basis of an explanation of consciousness. The discussion was moderated by Deepak Chopra, MD.

Among the discussants was Stuart Hameroff, MD, professor of anesthesiology and psychology and director of the Center of Consciousness Studies at the University of Arizona. Together with British physicist Roger Penrose, Hameroff espouses the idea that perception and consciousness arise from the collapse of the wave function of a Bose-Einstein condensate of quantum-entangled electrons in the brain.

Alford, a theoretical physicist who studies quark matter, was invited to join the discussion because he had previously defended a position that severely limits the metaphysical implications of physics. In an article that appeared in the Foundations of Physics in 2006, he asserted that physics can “only cover limited aspects of our experience.”

Alford questioned the idea of quantum mind, explaining that quantum entanglement is “usually very delicate” and “difficult to arrange.” Physicists struggle to entangle even a few particles for any substantial period of time. It seems improbable, he said, that “these very delicate processes are the crucial feature of the functioning of the human brain,” which is “not a suitable environment” for quantum subtlety.

“It’s more likely,” he said, “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. You don’t need to reach all that way."

Chopra went on to say “matter is an illusion and only consciousness is real.”

The entire two-hour debate over the quantum mind can be viewed at the Philoctetes website.

The Wikipedia article on the Penrose-Hameroff model is well-researched and provides a good section on objections to the model.

From the last footnote (39) of the wiki article, citing Phys. Rev. E 80 (2009):

"Penrose and Hameroff have argued that the conventional models of a brain function based on neural networks alone cannot account for human consciousness, claiming that quantum-computation elements are also required. Specifically, in their Orchestrated Objective Reduction (Orch OR) model [R. Penrose and S. R. Hameroff, J. Conscious. Stud. 2, 99 (1995)], it is postulated that microtubules act as quantum processing units, with individual tubulin dimers forming the computational elements. This model requires that the tubulin is able to switch between alternative conformational states in a coherent manner, and that this process be rapid on the physiological time scale. Here, the biological feasibility of the Orch OR proposal is examined in light of recent experimental studies on microtubule assembly and dynamics. It is shown that the tubulins do not possess essential properties required for the Orch OR proposal, as originally proposed, to hold. Further, we consider also recent progress in the understanding of the long-lived coherent motions in biological systems, a feature critical to Orch OR, and show that no reformation of the proposal based on known physical paradigms could lead to quantum computing within microtubules. Hence, the Orch OR model is not a feasible explanation of the origin of consciousness."

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