Can you master the ideas of Plato, Kant, Nietzsche and Sartre? What does "I think, therefore I am" really mean? Do you know the arguments for and against the existence of God? And what do the great philosophers tell us about knowledge and truth, good and evil? Packed with bite-sized briefings, shortcuts, and even a few bluffs, this guide demystifies 50 key philosophical concepts and provides you with all you need to speak out about the very biggest ideas, including ethics, relativism, capitalism, the Social Contract, Existentialism, metaphysics, Chinese philosophy, and many more.