Sleep

Why do humans sleep? Scientists may not know the answer to this question, but I do: it's because we're tired. Especially the parents.

I suppose, though, that that isn't the "why" the scientists are after.

Let me try again. My explanation for why humans sleep is something that will make sense to most parents of newborns, and indeed it occurred to me as I tried to get a baby of mine to go back to sleep one night.

My explanation is a simple evolutionary explanation. It may ultimately be question-begging, but don't let that deter us. So here goes. The traits we have are the traits our evolutionary ancestors had. These ancestors are the ones who lived to be old enough to reproduce. Not everyone lived to be that old. Some children died before they were physically mature enough to have babies and pass on their traits. Now suppose that "back in the day" there were two kinds of infants: those who slept a lot and those who did not. Other things equal, which would be more likely to survive? Yeah, parents, you know the answer to this question, and you know the why, too. Dare I say it? Very well. Parents need a break. Babies are lots of things (saccharin here), but they are also time-consuming, ear-splitting, arm-tiring, shower-shortening, laundry-producing, plan-ruining, conversation-interrupting, etc., etc. pains in the asses. Parents who did not get a break from their children because their children did not sleep would, I submit, be more likely to suffer from baby-rage and kill their children. These children would not grow up to reproduce and pass on their non-sleeping ways to subsequent generations. The children who were most likely to survive were the sleepers. The sleepers procreated and passed this trait on down the line to us.

So why do we sleep? In short, because our parents would have killed us if we didn't.

P.S. In assessing the above claims, please keep in mind that I am not a scientist, philosopher of science, or baby-killer. Thanks.