In this book, Nicholas Rescher seeks to settle debates about whether Galen originated the fourth figure of the categorical syllogism. For his definitive evidence, Rescher examines Arabic sources, one of which is “On the Fourth Figure of the Syllogism” by twelfth-century mathematician Ibn al-Salah, and is reproduced here in Arabic with an annotated English translation. Rescher also explores the history and importance of the syllogistic figures in the evolution of logic in Islamic and European cultures, and discusses the debate about the actual number of syllogistic figures.

Nicholas Rescher is Distinguished University Professor of Philosophy at the University of Pittsburgh and co-chairman of the Center for Philosophy of Science. A member of the American Academy of Arts and Sciences, he has served as president of the Eastern Division of the American Philosophical Association, the Leibniz Society of North America, the Charles S. Peirce Society, the American Catholic Philosophical Association, and the Metaphysical Society of America. Rescher is the author or editor of more than one hundred books, including Ignorance (On the Wider Implications of Deficient Knowledge), Philosophical Inquiries: An Introduction to Problems of Philosophy, and A Journey through Philosophy in 101 Anecdotes.