Nicholas Rescher is distinguished university professor of philosophy at the University of Pittsburgh. In a research career extending over six decades, he has published over three hundred articles and written over a hundred philosophy texts, including A System of Pragmatic Idealism, The Limits of Science, Conditionals, Philosophical Reasoning: A Study in the Methodology of Philosphizing, Enlightening Journey: The Autobiography of an American Scholar, and Unknowability: An Inquiry Into the Limits of Knowledge.