Medieval logicians advanced far beyond the logic of Aristotle, and this book shows how far that advance took them in two central areas. Broadie focuses upon the work of some of the great figures of the fourteenth century, including Walter Burley, William Ockham, John Buridan, Albert of Saxony, and Paul of Venice, and deals with their theories of truth conditions and validity conditions. He reveals how much of what seems characteristically twentieth-century...