In his book, The Nature of Historical Explanation, Patrick Gardiner asked a worthwhile question:
“In what sense can I be said to know an event which is in principle unobservable, having vanished behind the mysterious frontier which divides the present from the past? And how can we be sure that anything really happened in the past at all, that the whole story is not an elaborate fabrication, as untrustworthy as a dream or a work of fiction?”