Discover the 50 key ideas that have defined the course of philosophical inquiry in this thought-provoking and accessible guide. What is truth? How can I lead an ethical life? Do I have free will? Questions such as these have plagued world-famous philosophers since ancient times. Find out how they have sought to answer them and more in this captivating guide to philosophy, unpacking the subject's most intriguing and profound reflections, including: - Plato's cave - The Stoic elimination of emotion - Descartes's Cogito Ergo Sum - Nietzsche's Superman - Logical Positivism - The world as a computer simulation Written in plain, jargon-free English with helpful diagrams, this essential guide untangles complicated theories and makes abstract concepts accessible to everyone. Perfect for students or anyone wanting a fresh approach to this incredible subject.