These two treatments of the predicate are typical of the two traditions in traditional logic—the intensional and the extensional traditions. Logicians who can be counted among the intensional logicians are Gottfried Leibniz, Johann Lambert, William Hamilton, Stanley Jevons, and Hugh MacColl. Among the extensional logicians are George Boole, Augustus De Morgan, Charles Peirce, and John Venn.
Source: wiktionary