> it could be that we're stuck on a very deep local minimum I think that's likely. Also, in cases where being able to be awake continually (e.g. high predatio

> it could be that we're stuck on a very deep local minimum I think that's likely. Also, in cases where being able to be awake continually (e.g. high predation or flying over water) animals have evolved unihemispheric sleep, which is likely a shorter evolutionary path and largely satisfies the selective pressure, making it less likely for sleep to be entirely evolved away.