Ruth Barcan Marcus 1921 – 2012

Ruth Barcan Marcus was an American philosopher and logician and one of the principal architects of twentieth-century quantified modal logic. Her doctoral thesis, written in 1946, contained the formal system now known as the Barcan formula and laid the foundation for the philosophical interpretation of modal logic that would later be developed by Kripke, Lewis, and others. She defended a direct-reference theory of names well before its more famous later articulation, made important contributions to deontic logic and ethics, and held the Halleck Professorship at Yale. Her Modalities collects her major essays.