In 1968, David Lewis decides that one truth can unify every theory he's had about the nature of the universe. It is the truth that every possible world is equally real. Lewis not only argues for this view, but devises a distinctive way of arguing for it, a method of doing philosophy that is as influential as his views. Meanwhile, a soon-to-be colleague and rival, Saul Kripke, reads Lewis' paper and fires off eight objections, and on the other side of the world, an entire continent becomes enamored with the life and works of David Kellogg Lewis, an admiration that survives to this day. Guest voices include Frank Jackson, Alan Hajek, John Bigelow, Helen Beebe, Anthony Fischer, Peter Anstey, and David Lewis.

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