There are various competing theories because each of them fails to capture everything funny. Yes, jokes release psychological tension, but so does a bath. Yes, we laugh at the misfortune of others (a fat lady falling into a pool) but often we find their misfortune upsetting instead. Meanwhile the opposite of misfortune can be hilarious, such as team’s worst player doing something unexpectedly miraculous.
Laughter is a human universal, found in all cultures, everywhere, in all times. Yet there is no clear reason why we get a burst of joy when something is funny, and even after centuries of trying, we can’t precisely define what “funny” is. We can understand jokes but usually can’t explain what it is about them that makes us laugh. Whenever we can, they aren’t as funny. All this is very strange. How can we understand and not understand something at the same time?