Friday, November 7, 2014

Methodological dualism?

In this article, one Professor McFadden from molecular genetics reviews some recent evidence for quantum effects in biological systems; or more accurately, mechanisms that exploit quantum effects to explain some biological capacity. McFadden considers a range of phenomena that rely on quantum mechanisms to explain what is going on biologically. He includes discussions of fruit fly olfaction based on quantum tunneling, bird navigation based on quantum entanglement, enzyme function based on quantum tunneling, and photosynthesis based on the capacity to harness “quantum coherence” to force photon energy to travel by “all possible routes” (within a chlorophyll molecule) “simultaneously.”

Now, I have no real idea what all of this means. I have at best a vague impressionistic understanding of quantum mechanics. What I get from this piece, however, is that seemingly intelligent people are taking the possibility of quantum mechanisms in biology very seriously. They are devising theories, gathering evidence, testing hypotheses, doing experiments, building models…you know, doing science. And all of this despite a huge huge problem. Here’s McFadden:

Beneath all these quantum solutions to puzzling vital phenomena, we find ourselves with a deeper mystery. Quantum coherence is an immensely delicate phenomenon, depending on those in-tune particle waves. To maintain it, physicists usually have to enclose their systems within near-perfect vacuums and cool them down to very close to absolute zero temperature to freeze out any heat-driven molecular motion. Molecular vibrations are the mortal enemy of quantum coherence. How, then, does life manage to maintain its molecular order for long enough to perform its quantum tricks in warm and wet cells? That remains a profound riddle.

Thus, despite the fact that he and his fellows currently have no idea whatsoever how to implement such quantum systems within large messy systems of molecules they consider it an open and legitimate question whether the biological systems they are studying implement such kinds of mechanisms.  And, I suspect, that despite this central “mystery” the work is considered legitimate, even if on the speculative end of the inquiry spectrum.

I confess to being very jealous. The mainstream cog-neuro community regularly dismisses more cognitive/behavioral accounts from areas like linguistics by asserting that the representational and computational models proposed are, in their view, just incompatible with the connectionist mechanisms many of them take as the brain’s own computational system. There is plenty of reason to be skeptical of such confident assertions concerning how the brain computes. As I’ve noted more than once, Gallistel and King have reviewed some of these objections and found them, ahem, wanting. But say that this was so. Say, contrary to fact that there was some reason to think that connectionism was the way the brain thought. Why not take a McFadden view of things? Here’s one set of data saying the brain does X and here’s another set saying that it does Y and we have a “profound riddle” requiring us to reconcile the differences. Embracing the problem, rather than summarily solving it by ignoring half, is the rational strategy. True, there is no Nobel prize for those admitting ignorance, but heh, we’re not in it for the money or the glory, are we? 

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