This document discusses defining philosophy and its purpose. It explores two notions of definition from Aristotle and Wittgenstein and considers philosophy as the love of knowledge, the mother of all disciplines, a space for questions, and a master of critical thinking. The document also lists branches of philosophy like metaphysics, epistemology, and ethics. It examines philosophical methodology and considers why philosophy is important both institutionally and informally. Finally, it outlines how philosophy can be used to tie up loose ends, test reasonableness, and ensure proper logical structure across various fields like science, social science, engineering, and literature.