When we think about memories, what happens? Obviously, they don't exist in reality in front of us. So we do some sort of mapping from the past to the present and try to let it permeate what is in front of us.

Memories are kind of like the Moon in a solar eclipse. If you're not familiar, in a total solar eclipse, the moon passes directly between the Sun and Earth, casting a shadow on Earth and blocking all of the Sun's light. If you want to generate a memory properly, you have to make sure the Moon completely crosses and you forget the present. Otherwise, it's impossible to remember the past and live in the present.