History is nothing but assisted and recorded memory. It might almost be said to be no science at all, if memory and faith in memory were not what science necessarily rest on. In order to sift evidence we must rely on some witness, and we must trust experience before we proceed to expand it. The line between what is known scientifically and what has to be assumed in order to support knowledge is impossible to draw. Memory itself is an internal rumour; and when to this hearsay within the mind we add the falsified echoes that reach us from others, we have but a shifting and unseizable basis to build upon. The picture we frame of the past changes continually and grows every day less similar to the original experience which it purports to describe.