Possible worlds

Possible worlds are like different versions of the world we live in. They are like different stories in a book that all start off the same way but end differently. For example, if you had a book about a person's life, one possible world might be that the person becomes famous and rich. Another possible world might be that the person becomes very successful at their job and has a happy family. We live in one possible world - the world that actually exists - but lots of other possible worlds could have been true.