Non-Contradiction - Paperbackby Lawrence H. Powers (Author), Hans V. Hansen (Foreword by) Larry Powers' Non contradiction is an engaging, innovative, and delightful book. It re tells the story of Greek philosophy from the novel starting point that Parmenides, Plato and Aristotle took their primary philosophical task to be the defence of the principle of non contradiction. In the course of nine chapters devoted to ancient Western philosophy we see Powers as the ally of the Greeks,