Question: Why do dreams and nightmared exist

Artem Evdokimov answered on 21 Jun 2012:

Very good question!

There are several theories about dreaming (nightmares included). One theory says that dreams are the side effect of how brain organizes information that it wants to keep (how it creates associations and memories). The other theory says that dreams are literally ‘games’ – scenarios that brain creates for itself in order to learn how to survive in the real world. Thus nightmares are scenarios where the brain puts us in virtual danger, and then looks for solutions – like running away from a tiger in real life would only give you one chance to do it right (or you get eaten) whereas in a dream the brain can explore multiple alternatives and find one that feels right.