This is the third of a four part series on Ibn Khaldun (1332-1406), the African Arab intellectual widely considered to be the founder of sociology and the philosophy of history. We will be reading from the introduction of his Muqaddimah ("Prolegomena"), and discussing his insights on historical methodology, some epistemological problems they raise, and their continued relevance in contemporary life. In part three, we examine Ibn Khaldun’s assertion that history should be treated as a branch of philosophy, in the context of the ‘philosophy’ as understood by classical Islamic ‘falasifa’ such as al-Farabi. We discuss his critique of historians who do not apply the ‘yardstick of philosophy,’ and the prospect of distinguishing historical cultural conditions from unchanging principles of nature, knowledge of which he claims is required to understand history.