Why did Archimedes jump from his bath and run naked through the streets shouting 'Eureka!'? What is a quantum and where does it leap? Do you know your id from your ego? Does God play dice? This books answers all those questions and more, taking the revolutionary and perplexing ideas of Western thought and extracting their essence. From Greek philosophy to contemporary economics, physics and architecture, A Little Knowledge covers some of the most often heard but least understood theories and explains them simply and entertainingly, including: Existentialism; The Oedipus Complex; Original Sin; 'I think, therefore I am'; Fuzzy Logic; The Big Bang; and 'Religion is the Opium of the People'.