science · Still open
Why Do We Dream?
Every night you hallucinate vividly for two hours. Nobody knows why.
What we know
Dreams concentrate in REM sleep. Memory consolidation improves after sleep.
The edge
No experiment has established what dreaming is for — every major theory has strong counterexamples.
Open questions
Would a person who never dreamed be cognitively impaired?
Sit with it
Tonight you will invent worlds and forget them. What would it mean if that had no purpose at all?