I agree that the human brain is roughly at a local optimum. But think about what could be done just with adding a fiber optic connection between two brains (I think there are some ethical issues here so this is a thought experiment, not something I recommend). The two brains could be a kilometer apart, and the signal between them on the fiber optic link takes less time than a signal takes to get from one side to the other of a regular brain. So these two brains could think together (probably with some (a lot?) neural rewiring) as fast as a regular brain thinks individually. Repeat with some more brains.
Or imagine if myelination was under conscious control. If you need to learn a new language, demyelinate the right parts of the brain, learn the language quickly, and then remyelinate it.
So I think even without changing things much neurons could be used in ways that provide faster thinking and faster learning.
As for energy efficiency, there is no reason that a superintelligence has to be limited to the approximately 20 watts that a human brain has access to. Gaming computers can have 1000 W power supplies, which is 50 times more power. I think 50 brains thinking together really quickly (as in the interbrain connections are as fast as the intrabrain connections) could probably out-think a lot more than 50 humans.
And, today, there are supercomputers that use 20 or more megawatts of power, so if we have computing that is as energy efficient as the human brain, that is equivalent to 1 million human brains (20e6/20), and I think we might be able to agree that a million brains thinking together really well could probably out-think all of humanity.
I agree that the human brain is roughly at a local optimum. But think about what could be done just with adding a fiber optic connection between two brains (I think there are some ethical issues here so this is a thought experiment, not something I recommend). The two brains could be a kilometer apart, and the signal between them on the fiber optic link takes less time than a signal takes to get from one side to the other of a regular brain. So these two brains could think together (probably with some (a lot?) neural rewiring) as fast as a regular brain thinks individually. Repeat with some more brains.
Or imagine if myelination was under conscious control. If you need to learn a new language, demyelinate the right parts of the brain, learn the language quickly, and then remyelinate it.
So I think even without changing things much neurons could be used in ways that provide faster thinking and faster learning.
As for energy efficiency, there is no reason that a superintelligence has to be limited to the approximately 20 watts that a human brain has access to. Gaming computers can have 1000 W power supplies, which is 50 times more power. I think 50 brains thinking together really quickly (as in the interbrain connections are as fast as the intrabrain connections) could probably out-think a lot more than 50 humans.
And, today, there are supercomputers that use 20 or more megawatts of power, so if we have computing that is as energy efficient as the human brain, that is equivalent to 1 million human brains (20e6/20), and I think we might be able to agree that a million brains thinking together really well could probably out-think all of humanity.