There is a field of study known as the philosophy of history. But rather diverse content is treated under that heading. The subject matter of the philosophy of history may be historical knowledge as such, its nature, its limits, its forms. When this is its content, the philosophy of history is, strictly speaking, the theory of knowledge as applied to history. The philosophy of history may also embrace the study of the general laws of historical existence as revealed in the destiny of mankind. Here philosophy of history is, in its essence, the general theory of the historical process. The purpose of philosophy of history may be seen as elucidation of the question as to the meaning of history: does it have any meaning at all and, if so, what is it; and moreover what precisely are we to understand by "meaning" when we are talking about history? Finally, the term philosophy of history may be employed to denote reflections on the usefulness of history: is the historical experience of mankind projected into its subsequent destiny? Does it influence men's acts in history? Does it teach anyone anything?