The Watchmaker: my fav argument

[polymath257]

Recently I've read criticism that says brain science may be approaching things in a way that's even more outmoded than that. The fact that current neuroscience explanations are very materialistic, cause and effect type of formulations, may in fact be stuck in a Newtonian world that physicists have long discarded. If modern physics accepts entangled telepathic particles, non locality, and retro causation, then it isn't crazy to look for these effects in the brain. We know that birds use quantum effects in navigation, for example, so we have no a priori reason to rule them out in humans. What the brain does may turn out to be a lot stranger than we are currently imagining.

Yes, there is a reason to rule them out, at least for the most part.

The reason is that Planck's constant is small. Which means that the differences between Newtonian and quantum physics tend to happen at the atomic level and below. Once you get to the size of macromolecules, the differences are pretty insignificant.

There are two exceptions that I know of: photosynthesis depends on the quantum aspects of the chlorophyll molecule. There are stages where a quantum superposition is important for the energy transfer. The other case is that the receptors in our eyes (the rods) are sensitive to single photons. In a very dark room, that can amplify the quantum aspects of photons to macroscopic levels. Once you get to even a moderately dark room, however, there are enough photons that the quantum aspects get averaged away.

Navigation depends on magnetism, that seems pretty clear, but the claims that quantum entanglement are relevant for that seem very doubtful to me. Once again, it is a noisy environment at temperatures well above absolute zero, so quantum effects tend to be washed out.

I've seen claims that microtubules in the brains amplify quantum effects and are related to consciousness. Frankly, I don't buy it. Again the scale of even one monomer in a microtubule is large enough that quantum effects would be swamped.

The Newtonian approximation is incredibly good once you get above the level of atoms. It certainly hasn't been discarded as the go-to physics in biology and it shouldn't be.