I see a few problems with that. For example that we can freely act and think in reality but cannot in (non-lucid) dreams. Things like meditation seem more convi

I see a few problems with that. For example that we can freely act and think in reality but cannot in (non-lucid) dreams. Things like meditation seem more convincing. Though it is an interesting thought experiment, which implies that we evolved much farther than necessary for dreaming simply because the environment outside dreams as an energy source is so competitive, to a point we're now able to create different kinds of alternate realities as well. Which as so often leads to questions like the purpose of our existence. To me the idea that dreams exist in order to let the brain filter out unimportant experiences from the day before - or highlight important ones - seems more plausible, especially considering sleep deprivation can lead to hallucinations and more, I don't think this can be explained purely with other processes like the self-cleaning mechanisms of the brain during sleep.