This document discusses the definition and nature of philosophy. Philosophy is defined as the love of wisdom and the analysis of concepts through reasoning. It originated from the Greek words for love and wisdom. The main branches of philosophy are logic, metaphysics, epistemology, and value theory. These deal with reasoning, abstract concepts, the nature and validity of knowledge, and values. The document also discusses the relationship between library science and philosophy, noting they are closely linked through exploring theories behind librarianship.