We dream to keep our brains working

We dream to keep our brains working.The continual activation theory proposes that your dreams result from your brain's need to constantly consolidate and create long-term memories
in order to function properly.So when external input falls
below a certain level,like when you're asleep,your brain automatically triggers the generation of data from its memory storages,which appear to you in the form of the thoughts and feelings you experience in your dreams.In other words,
your dreams might be a random screen saver your brain turns on
so it doesn't completely shut down.