Most of us forget more than we remember. We change memories to make sense of what has happened in our lives. When we then recall a memory, we reconstruct the events in our minds and even shape them to fit in with any new information.

Many of us think of our past as a kind of a video library where we can look at records of our lives. If memories were fixed like videotapes, you would find it difficult to imagine a new situation.

Although some physicists would argue against the existence of time, we all do have a perception of time that reflects the reality of our lives on Earth.