Port-Royal Logic

Port-Royal Logic, or Logique de Port-Royal, is the common name of La logique, ou l'art de penser, an important textbook on logic first published anonymously in 1662 by Antoine Arnauld and Pierre Nicole, two prominent members of the Jansenist movement, centered around Port-Royal. Blaise Pascal likely contributed considerable portions of the text. Written in the vernacular, it became quite popular and was in use up to the twentieth century, introducing the reader to logic, and exhibiting strong... full article at wikipedia