Maybe the reason has to do with how we wake up. Our bodies must hit a certain state in order to sleep, and in order to exit sleep. If sleeping were a voluntary action, we’d either need to remain partially conscious, or else we’d go to sleep forever. If our bodies and minds have hardcoded conditions for sleep, however, this will never be a problem under normal circumstances.
So, here’s my thought:
Maybe the reason has to do with how we wake up. Our bodies must hit a certain state in order to sleep, and in order to exit sleep. If sleeping were a voluntary action, we’d either need to remain partially conscious, or else we’d go to sleep forever. If our bodies and minds have hardcoded conditions for sleep, however, this will never be a problem under normal circumstances.