A classic introductory text in this discipline was co-written by George Edward Hughes and his student Max Creswell. Quine devised three levels of involvement in this discipline, objecting to introducing quantification at the third, but his concerns were put solidly to rest by Ruth Barcan Marcus and her formula. The Finnish philosopher G.H. von Wright extended this discipline to ethics, founding a "deontic" variant of it. This discipline grew out of the S4 and S5 systems of (*) Clarence Irving Lewis, who originated the notion of strict implication. It's not philosophy of language, but the distinction between vivid and 
A classic introductory text in this discipline was co-written by George Edward Hughes and his student Max Creswell. Quine devised three levels of involvement in this discipline, objecting to introducing quantification at the third, but his concerns were put solidly to rest by Ruth Barcan Marcus and her formula. The Finnish philosopher G.H. von Wright extended this discipline to ethics, founding a "deontic" variant of it. This discipline grew out of the S4 and S5 systems of (*) Clarence Irving Lewis, who originated the notion of strict implication. It's not philosophy of language, but the distinction between vivid and rigid designators is crucial to this discipline. This was the initial discipline for which a teenage Saul Kripke designed a set of semantics. This discipline uses accessibility relations, as well as the square and diamond symbols, to make statements about possible worlds. For 10 points, name this form of formal logic in which the operators can express possibility, impossibility, and necessity
A classic introductory text in this discipline was co-written by George Edward Hughes and his student Max Creswell.