This work is both an analysis of one of the most important theories on signs and signification of the Middle Ages and a spirited defense of the objectivity of knowledge. The author compares the sign theory of the medieval epistemologist John of St. Thomas to that of the great Swiss linguist Ferdinand de Saussure. He finds that John of St. Thomas’ theory endures as the more philosophically compelling because it describes the relationship between reference and representation in a manner that shows why thought and language must be fundamentally objective. The medieval theorist stands in opposition to the subjectivism and irrationalism associated with much of current research in semiotics.