Philosophy of education, philosophical reflection on the nature, aims, and problems of education. The philosophy of education is Janus-faced, looking both inward to the parent discipline of philosophy and outward to educational practice. (In this respect it is like other areas of “applied” philosophy, such as the philosophy of law, the philosophy of science, and the philosophy of medicine, including bioethics) This dual focus requires it to work on both sides of the traditional divide between theory and practice, taking as its subject matter both basic philosophical issues (e.g., the nature of knowledge) and more specific issues arising from educational practice (e.g., the desirability of standardized testing). These practical issues in turn have implications for a variety of long-standing philosophical problems in epistemology, metaphysics, ethics, and political philosophy. In addressing these many issues and problems, the philosopher of education strives for conceptual clarity, argumentative rigor, and informed valuation.