This Filo Notes whiteboard session introduces philosophy, defining it etymologically as "love of wisdom" (philia and Sophia) – a strong desire for and correct application of knowledge.  Traditionally, philosophy is viewed as a science studying beings (all existing things, material or immaterial) and their ultimate causes using reason alone.  Key philosophical questions include the origin of the world, the existence of God, the meaning of life, and ethical dilemmas like euthanasia.  Philosophy employs reason, critical thinking, and logical analysis.  However,  philosophers disagree on its definition; Karl Jaspers, for example, prioritizes questions over answers.

The session then outlines philosophy's four main branches: metaphysics (study of things beyond the physical, subdivided into general metaphysics/ontology – studying being and existence – and special metaphysics, including cosmology, psychology/anthropology, and theodicy); epistemology (study of knowledge, its nature, scope, and justification); logic (study of correct thinking and valid arguments); and ethics (study of moral human actions, right conduct, and the good life, distinct from morality, which is the practice).  Each branch's core questions and sub-disciplines are briefly discussed, emphasizing the schematic nature of the overview.