Don't infer based on the fact that something is as it is, that it is therefore superior to all other possibilities.
Actually, we can conclude that there must be a good reason why the average human needs eight hours of sleep, as opposed to four hours or two hours or half an hour. It's not as if we can't get there from here: Some living humans really do need only four hours of sleep. And other creatures, not so different from us, have much niftier tricks: Bears can sleep for four months straight, horses can sleep very lightly while standing up, my parrot wakes up at almost any stimulus, some creatures sleep with half the brain at once, etc. If sleep were a big liability, there seem to be lots of genetic switches that could be thrown to reduce, alter, or eliminate it. The fact that those switches have not been thrown in us suggests that our sleep pattern is an equilibrium point in evolutionary space.
Now, maybe you're trying to say that, although there might be a way to design a brain that didn't need sleep -- perhaps scientists will use futuristic neuron-CAD software to figure that out, someday -- some accident in early evolution sent us down this particular branch, and now we can't get there from here. That's true, and it's really fascinating. It seems that creatures without sleep would have to evolve nearly from scratch -- because even fruit flies sleep (a fact that I didn't know until today) which suggests that you have to go back past our common ancestor with the insects to find a creature that wasn't designed around sleep. And if such a creature with a prototype sleep-free brain tried to start up shop today, odds are it or its descendents would all be eaten by fish before they got very far. It's hard to evict species from an ecological niche, particularly when you're going up against nearly every animal species on earth.
Actually, we can conclude that there must be a good reason why the average human needs eight hours of sleep, as opposed to four hours or two hours or half an hour.
Now, maybe you're trying to say that some accident in early evolution sent us down this particular branch, and now we can't get there from here. That's true, and it's really fascinating.
That was indeed the idea behind my previous post. Rather the same thing happens with humans only changing teeth once a lifetime instead of continuously. There is some evidence that changing once doesn't give us an evolutionary advantage, but is simply a leftover from some ancestor's trait way back. (I'll see if I can find the reference).
I'm not saying that humans might not need their sleep (we die if we are sleep deprived), but that, based on the fact that we sleep, you can't claim that sleeping creatures have an advantage over hypothetical non-sleeping creatures. Maybe it's just something that stuck and doesn't do enough harm to kill us all out.
I don't exactly agree with this, though:
Don't infer based on the fact that something is as it is, that it is therefore superior to all other possibilities.
Actually, we can conclude that there must be a good reason why the average human needs eight hours of sleep, as opposed to four hours or two hours or half an hour. It's not as if we can't get there from here: Some living humans really do need only four hours of sleep. And other creatures, not so different from us, have much niftier tricks: Bears can sleep for four months straight, horses can sleep very lightly while standing up, my parrot wakes up at almost any stimulus, some creatures sleep with half the brain at once, etc. If sleep were a big liability, there seem to be lots of genetic switches that could be thrown to reduce, alter, or eliminate it. The fact that those switches have not been thrown in us suggests that our sleep pattern is an equilibrium point in evolutionary space.
Now, maybe you're trying to say that, although there might be a way to design a brain that didn't need sleep -- perhaps scientists will use futuristic neuron-CAD software to figure that out, someday -- some accident in early evolution sent us down this particular branch, and now we can't get there from here. That's true, and it's really fascinating. It seems that creatures without sleep would have to evolve nearly from scratch -- because even fruit flies sleep (a fact that I didn't know until today) which suggests that you have to go back past our common ancestor with the insects to find a creature that wasn't designed around sleep. And if such a creature with a prototype sleep-free brain tried to start up shop today, odds are it or its descendents would all be eaten by fish before they got very far. It's hard to evict species from an ecological niche, particularly when you're going up against nearly every animal species on earth.