Editing Dana Scott (section)

===Modal and tense logic===
Scott also began working on [[modal logic]] in this period, beginning a collaboration with [[John Lemmon]], who moved to [[Claremont, California]], in 1963.  Scott was especially interested in [[Arthur Prior]]'s approach to [[tense logic]] and the connection to the treatment of time in natural-language semantics, and began collaborating with [[Richard Montague]] (Copeland 2004), whom he had known from his days as an undergraduate at Berkeley.  Later, Scott and Montague independently discovered an important generalisation of [[Kripke semantics]] for modal and tense logic, called [[Scott-Montague semantics]] (Scott 1970).

John Lemmon and Scott began work on a modal-logic textbook that was interrupted by Lemmon's death in 1966.  Scott circulated the incomplete monograph amongst colleagues, introducing a number of important techniques in the semantics of model theory, most importantly presenting a refinement of the ''canonical model'' that became standard, and introducing the technique of constructing models through ''filtrations'', both of which are core concepts in modern Kripke semantics (Blackburn, de Rijke, and Venema, 2001).  Scott eventually published the work as ''An Introduction to Modal Logic'' (Lemmon & Scott, 1977).