When faced with new evidence, an intelligent agent should ideally update on it and then forget it. The update is always about the present. The evidence remains entangled with the past, more and more distant as time goes by. Whatever part of it stops being true must be discarded.

Sense data is neither true nor false, it just is. Ideally, agents should store a somewhat-compressed version of it all - but of course, this is often prohibitively expensive.