Ok, fair enough, I overstated the case Scott Aaronson was making. It is my position however that Roger Penrose is wrong about the importance of quantum effects in neurons, so I was excited to find support in what Scott was saying. Here’s a specific passage from Roger Penrose and Stuart Hameroff’s paper “Consciousness in the universe; A review of the ‘Orch OR’ theory”:
“MT [microtubule] automata based on tubulin dipoles in hexagonal lattices show high capacity integration and learning [61]. Assuming 10^9 binary tubulins per neuron switching at 10 megahertz (10^7 ) gives a potential MT-based capacity of 10^16 operations per second per neuron. Conventional neuronal-level approaches based on axonal firings and synaptic transmissions (10^11 neurons/brain, 10^3 synapses/neuron, 10^2 transmissions/s/synapse) give the same 10^16 operations per second for the entire brain!”
Roger and Stuart make this claim in earlier papers as well. They also make claims about the microtubules being used in various ways for information storage. I think the information storage claims they make are likely exaggerated, but I’m not confident that there isn’t non-negligible information storage occurring via microtubule modification.
I will, however, state that I believe the microtubule computation hypothesis to be false. I think 10^15 − 10^16 operations per second is the correct estimate for the human brain.
If you want to try to figure out a bet to make on this, we could make a Manifold Market.
I think (on “philosophical” grounds) that quantum entanglement probably has a role in the brain, but if the microtubules are involved, I think it’s far more likely that each microtubule only contains one or a few logical qubits (stored as topological quantum information, entanglement that resists decoherence because it is wound around the cylinder, as in the Kitaev code).
Penrose is quite willing to say that a quantum computer accessing that natural noncomputable dynamics could have the same capabilities as the human brain.
Hmm, we’re still talking past each other. I’m saying I don’t believe any quantum weirdness is behaviorally relevant to the human brain or simulations thereof.
Just ordinary analog and digital computer chips, like in ordinary consumer electronics. Nothing special but the neural architecture and learning rules set up by the genome, and the mundane experience of life.
Right, and I disagree with the usual computational theory of mind (at least with respect to “consciousness” and “the self”), according to which the mind is a kind of virtual state machine whose microphysical details are irrelevant. There are sorites problems and binding problems which arise if you want to get consciousness and the self from physically coarse-grained states, which is why I look for explanations based in exact microphysical properties and irreducible complex entities instead.
Ok, fair enough, I overstated the case Scott Aaronson was making. It is my position however that Roger Penrose is wrong about the importance of quantum effects in neurons, so I was excited to find support in what Scott was saying. Here’s a specific passage from Roger Penrose and Stuart Hameroff’s paper “Consciousness in the universe; A review of the ‘Orch OR’ theory”:
Roger and Stuart make this claim in earlier papers as well. They also make claims about the microtubules being used in various ways for information storage. I think the information storage claims they make are likely exaggerated, but I’m not confident that there isn’t non-negligible information storage occurring via microtubule modification.
I will, however, state that I believe the microtubule computation hypothesis to be false. I think 10^15 − 10^16 operations per second is the correct estimate for the human brain.
If you want to try to figure out a bet to make on this, we could make a Manifold Market.
I think (on “philosophical” grounds) that quantum entanglement probably has a role in the brain, but if the microtubules are involved, I think it’s far more likely that each microtubule only contains one or a few logical qubits (stored as topological quantum information, entanglement that resists decoherence because it is wound around the cylinder, as in the Kitaev code).
Hmm, we’re still talking past each other. I’m saying I don’t believe any quantum weirdness is behaviorally relevant to the human brain or simulations thereof. Just ordinary analog and digital computer chips, like in ordinary consumer electronics. Nothing special but the neural architecture and learning rules set up by the genome, and the mundane experience of life.
Right, and I disagree with the usual computational theory of mind (at least with respect to “consciousness” and “the self”), according to which the mind is a kind of virtual state machine whose microphysical details are irrelevant. There are sorites problems and binding problems which arise if you want to get consciousness and the self from physically coarse-grained states, which is why I look for explanations based in exact microphysical properties and irreducible complex entities instead.