Don’t Assume Quantum Physics Doesn’t Matter

85 years after the formulation of quantum mechanics, it is still often assumed that distinctively quantum phenomena have no role to play in explaining life or mind. I think this assumption is unjustified.

Clearly scientific models have done an excellent job across a variety of fields (including molecular biology and bio-chemistry) with no need to invoke quantum effects like superposition and entanglement. It’s almost as if nature was tempting us to believe we live in an essentially classical world -- with quantum physics safely relegated to the laboratory. But now we’re beginning to learn about the exploitation of quantum effects in biology. While we already had an in-depth understanding of photosynthesis, it turns out that the process is made much more efficient by utilizing quantum coherence. I think this example shows that progress in quantum biology is made challenging by the technological sophistication needed to detect such processes -- but it’s also true that we won’t discover them if we assume they don’t exist. Hopefully recent results will spur many new research programs in this area.

We can try to speculate in advance of the science: when done well this can suggest avenues for research (I think Stuart Kauffman, the subject of the last post, does a fine job of this). But I wonder if the ubiquity of a philosophical materialism seemingly inspired by classical physics holds us back. For example it’s surprising to me that scientifically-oriented philosophers would still defend the thesis that the human brain/body system is not only (for all practical purposes) classical but deterministic, despite our grounding in quantum physics. For example Daniel Dennett, in his book Freedom Evolves, argues for determinism and compatibilism about free will. In doing so he assumes at the outset that the details of microphysics do not matter until proven otherwise. I thought that was backwards: why wouldn’t natural selection exploit the indeterminism of quantum mechanics and its other distinctive features? The goal should be to figure out how and to what extent. (It’s also possible QM was needed to “get off the ground” – some ideas toward solving the problem of the origin of life suggest this).

Now I know part of the problem is that many of those who would invoke QM to explain the human mind in particular engage in rampant speculation or worse. In particular we are afflicted with some popular “new-age” authors who have an unfortunate propensity to link quantum mechanics to wishful thinking about paranormal abilities and the supernatural. This clearly taints the topic in the eyes of many. But there’s a false dichotomy at work here: the fact that QM fails to give us magical powers doesn’t make it irrelevant. On the topic of free will, a false dichotomy also seems to prevail: it’s true we have evidence that the folk conception of free will is deeply flawed, but it doesn’t follow that our brain/body systems have no freedom.

While the evidence is preliminary and the effects may be subtle, I predict that 85 years from now it will be well understood that non-trivial quantum effects play an important explanatory role in life and mind.