Probably true, and this could mean the brain has some substantial advantage over today’s hardware (like 1 OOM, say) but at the same time the internal mechanisms that biology uses to establish electrical potential energy gradients and so forth seem so inefficient. Quoting Eliezer;
I’m confused at how somebody ends up calculating that a brain—where each synaptic spike is transmitted by ~10,000 neurotransmitter molecules (according to a quick online check), which then get pumped back out of the membrane and taken back up by the synapse; and the impulse is then shepherded along cellular channels via thousands of ions flooding through a membrane to depolarize it and then getting pumped back out using ATP, all of which are thermodynamically irreversible operations individually—could possibly be within three orders of magnitude of max thermodynamic efficiency at 300 Kelvin. I have skimmed “Brain Efficiency” though not checked any numbers, and not seen anything inside it which seems to address this sanity check.
Probably true, and this could mean the brain has some substantial advantage over today’s hardware (like 1 OOM, say) but at the same time the internal mechanisms that biology uses to establish electrical potential energy gradients and so forth seem so inefficient. Quoting Eliezer;