Monday, January 23, 2006

Davies on Quantum Biology

I mentioned in this recent post that I thought efforts to investigate the possible role of quantum mechanics in human consciousness might be putting the “cart before the horse”. That is, I wondered if we can learn whether QM effects were utilized in simpler biological systems. So, I’ve been casting about for information on this topic.

Paul Davies wrote an article entitled “Does quantum mechanics play a non-trivial role in life?” (2004)which seemed to be a good brief review of the topic.

While Davies has written a large number of popular books and articles on scientific and philosophical subjects which appear pretty speculative (I’ve not read him before), this article seems like a clear-eyed survey of scholarly research on this subject.

And it does have a sobering conclusion. The subject, as summarized in the article, is very long on circumstantial evidence and hints, but he characterizes the case for quantum biology as one of “not proven”. A crucial challenge is related to decoherence. Quantum information processing effects which make use of coherent entangled quantum states need to be sheltered from and co-exist with other biochemical processes which appear to operate in decohered states which can be classically analyzed.

The good news is that there seem to be many leads to be followed up by researchers (Davies lists 7 areas of possibility in addition to the general area of “origin of life”); the bad news is there wouldn’t seem to be any results yet that would force greater attention to the area among those inclined to presume the classical paradigm is good enough.

2 comments:

Mike Wiest said...

Thanks for bringing my attention to the Davies paper, and for continuing to consider the quantum approach even though you are somewhat skeptical. I haven't read the Davies paper yet but I'm looking forward to it.... Here I was just going to suggest a few other sources about quantum biology.

I agree with your point that if there is a quantum substrate for human consciousness, we should see precursors in earlier life forms. Cairns-Smith calls this the "principle of evolutionary accessibility" in his book "Evolving the Mind," which argues for a quantum mind. That book is more of a primer though, which makes the quantum idea plausible but doesn't propose any particular theory. (Still, it's a good book!)

"The Rainbow and the Worm" by Mae-Wan Ho is an engaging but pretty comprehensive book reviewing the kinds of effects you're talking about, and explaining from a rigorous physics point of view why it makes sense to expect many functions of "coherence" in living organisms.

One chapter of Ho's book covers "biophotons," which are very weak emission of visible light from all living tissue. This radiation has been known under various names (cf. mitogenic radiation in the 1920's) but only in recent decades has is become clear that biophotons are coherent, indicating the existence of a coherent state inherent in all living matter. This latter result is primarily the work of Popp in Germany (see e.g.
http://www.lifescientists.de/publication/pub2001-08.htm). Though we don't hear much about it, it would seem to be relevant to the question whether life involves macroscopic quantum coherence.

Another cool research program is Albrecht-Buehler's. He investigates "intelligence" in single-celled animals, and appears to have discovered an electromagnetic communication and info-processing channel in single-cells--i.e. they can see! Moreover, this signalling is dependent on the cytoskeleton. This work is not reviewed in Ho's book but you can see it at http://www.basic.northwestern.edu/g-buehler/summary.htm.
The intro blurb may be a bit silly but the work seems solid and is published in peer-reviewed journals.

I'd be interested to hear your thoughts on any of these findings. Probably I'll be back with my two cents on the Davies review...

Steve said...

Thanks very much, Mike. I will check this all out.