I agree there’s good reason to imagine that, had further selective pressure on increased intelligence been applied in our evolutionary history, we probably would’ve ended up more intelligent on average. What’s substantially less clear is whether we would’ve ended up much outside the present observed range of intelligence variation had this happened. If current human brain architecture happens to be very close to a local maximum of intelligence, then raising the average IQ by 50 points still may not get us to any IQ 200 individuals. So while there likely is a nearby region of decreasing f(x, x+1), it doesn’t seem so obvious that it’s wide enough to terminate in superintelligence. Given the notorious complexity of biological systems, it’s extremely difficult to extrapolate anything about the theoretical limits of evolutionary optimization.
I agree there’s good reason to imagine that, had further selective pressure on increased intelligence been applied in our evolutionary history, we probably would’ve ended up more intelligent on average. What’s substantially less clear is whether we would’ve ended up much outside the present observed range of intelligence variation had this happened. If current human brain architecture happens to be very close to a local maximum of intelligence, then raising the average IQ by 50 points still may not get us to any IQ 200 individuals. So while there likely is a nearby region of decreasing f(x, x+1), it doesn’t seem so obvious that it’s wide enough to terminate in superintelligence. Given the notorious complexity of biological systems, it’s extremely difficult to extrapolate anything about the theoretical limits of evolutionary optimization.