An examination of three primary texts: Plato’s Republic, David Hume’s Enquiry Concerning Human Understanding, and Jean-Paul Sartre’s “Existentialism is a Humanism”. The great 20th century philosopher Whitehead compared Western philosophy to a series of footnotes to Plato. This is especially true of the Republic, which is one of only two or three truly encyclopedic books on philosophy, and the only one written in an accessible style. It includes discussions of the nature of good and evil, political states, art and beauty, knowledge, ultimate reality, etc. within an investigation into the nature of justice. Unlike anthologies the Republic enables us to see how our answers to specific questions depend on an underlying world view, as much as on the specific arguments we formulate to justify them. Most of the course will be devoted to the Republic which is by far the longest of the three texts, but Hume and Sartre will show us major alternatives to the philosophy of the Republic.