What constitutes historical reality changes from era to era. A medieval chronicler may well have considered the appearance of a comet or the birth of a two-headed goat as history, while considering economic conditions or peasant daily life as something else. Today historians have opposite inclinations. However one defines and recounts historical reality, it is always only a tiny part of reality. The infinity of molecular, atomic and sub-atomic events taking place each moment have no place in history. Even the vast majority of human actions and phenomena still fall outside the borders of historical reality.

This exclusiveness of historical reality compared to the infinity of human reality as a whole is perhaps its most essential feature. It is this exclusiveness that enables history to fulfill its function. History is supposed to be the story of humanity. However, human reality is infinite, and cannot be ‘told’ exhaustively. So in order to tell the story of humanity, a particular part of human reality is singled out as ‘historical’, and it is assumed that the story of this particular part alone is the story of humanity. If historical reality is made to encompass too much of human reality, it is in danger of becoming useless.

Narrow as historical reality is, it is never narrowed down to the past alone. Rather, historical reality always stretches into the present and the future as well. The borders of historical reality define not only what was important in the past, but also what is important in the present, and what will be important in the future.