Who are we? How can we be happy? Does the universe have a purpose? Greek philosophers approached the big questions of life sometimes in a genuine scientific way, sometimes in mystic ways, but always in an imaginative fashion. Pythagoras considered a charlatan for claiming the doctrine of reincarnation, Socrates ranting at people in the street with provocative and unanswerable questions, Aristotle tutoring great generals: these are examples of how Greek thinkers dared to question traditional conventions and to challenge the prejudices of their age, sometimes putting their own lives at stake. Greek Philosophy as an independent cultural genre began around 600 BCE, and its insights still persist to our times.