Sleep isn't about cleaning. It might include cleaning, but I don't believe for a second that cleaning is the main function.

Why? Cleaning is easy to optimize yet sleep is evidently hard to optimize. Going unconscious for a big chunk of the day in a world where everything wants to eat you is a crazy price to pay, yet sleep is highly conserved across species under this extreme selective pressure. Even the animals famous for avoiding sleep don't really avoid sleep so much as bend the rules! Seals partially wake up to breathe, migrating birds sleep a hemisphere of their brain at a time, but they all sleep. This didn't happen because "pumps are slow" or "filtering is hard." Biology is excellent at copy-paste-reinventing that stuff. Optimizing the pumps and filters is not something evolution would have struggled to do if it could have meant not going unconscious for a third of the day. Especially for organisms with small brains where the transport logistics are trivial.

IMO the much more likely explanation is that the brain uses contrastive learning somewhere. We know animal brains don't use backpropagation to train and contrastive learning is one of the biggest competing family of techniques. Instead of using calculus and outer products to calculate derivatives, you feed real data and false data forward through the network and each neuron tracks and trains on the difference. This can be batched -- many CL techniques could handle 16 hours of real data followed by 8 hours of false data -- but the false data can't be put off forever, or the contrast signal goes away. Also, you probably want to inactivate I/O while the false data is flowing through. In other words: sleep emerges from first-principles on the category of neural network learning techniques that the brain probably uses.

I don't think anyone was seriously about to shoot up with sleep-replacement peptides, but also: don't. Let someone else figure this out the hard way.

If that were true, wouldn't you expect 50 year olds (who have mostly learned how to navigate life) to need little or no sleep? Seniors sleep only a little less than young adults, still 6-8 hours a night.

I think you overestimate the disadvantages of sleep. It's very species dependent, for some it might be a disadvantage because you're more vulnerable to predators, for others it's an advantage because you spend less energy. If you're safe you really only need enough wake time to eat and reproduce.

dreams are false data

> the much more likely explanation is that the brain uses contrastive learning somewhere

This doesn’t explain sleep in virtually brainless creatures. A metabolic root cause seems more likely.

I think we made a big mistake by using biological terms for computer processes and now we have people like you coming to the """natural""" conclusion of going full circle and applying computer terms back to biological processes.

There is virtually no parrelel between both worlds besides the naming and no one has any idea about what's going on for real.