What is history?
A usually chronological record of events, as of the life or development of a people or institution, often including an explanation of or commentary on those events: http://www.thefreedictionary.com/history
If a science of history were achieved, it would, like the science of celestial mechanics, make possible the calculable prediction of the future in history... if you want to keep reading go to : http://archaeology.about.com/od/hterms/qt/history_definition.htm