Dana Stewart Scott was born on October 11, 1932. He is an American logician who once held the position of Hillman University Professor emeritus in Computer Science, Philosophy, and Mathematical Logic at Carnegie Mellon University. He is now retired and lives in Berkeley, California. In 1976, he and Michael O. Rabin received the ACM Turing Award for their research on automata theory. His work with Christopher Strachey in the 1970s helped create modern methods for understanding the meaning of programming languages. He has also studied modal logic, topology, and category theory.

Early career

He earned his bachelor's degree in Mathematics from the University of California, Berkeley, in 1954. He completed his Ph.D. thesis on Convergent Sequences of Complete Theories with the guidance of Alonzo Church at Princeton, and presented his thesis in 1958. Solomon Feferman (2005) notes about this time:

After finishing his Ph.D., he went to the University of Chicago, where he worked as an instructor until 1960. In 1959, he collaborated on a paper with Michael O. Rabin, a colleague from Princeton, titled Finite Automata and Their Decision Problem (Scott and Rabin 1959). This paper introduced the idea of nondeterministic machines to automata theory. This work contributed to both being awarded the Turing Award for introducing this important concept in computational complexity theory.

University of California, Berkeley, 1960–1963

Scott held a position as an assistant professor of mathematics at the University of California, Berkeley. He worked on traditional problems in mathematical logic, especially set theory and Tarskian model theory. He showed that the axiom of constructibility cannot exist alongside a measurable cardinal, a finding that became an important milestone in the development of set theory.

During this time, he began supervising Ph.D. students, including James Halpern, who studied the independence of the Axiom of Choice, and Edgar Lopez-Escobar, who researched infinitely long formulas with countable quantifier degrees.

Scott also started exploring modal logic during this period. He worked with John Lemmon, who moved to Claremont, California, in 1963. Scott was interested in Arthur Prior’s method for analyzing tense logic and its relationship to how time is described in natural language. He also collaborated with Richard Montague, whom he had met during his undergraduate studies at Berkeley. Together, Scott and Montague discovered a significant extension of Kripke semantics for modal and tense logic, now known as Scott-Montague semantics.

Scott and Lemmon began writing a textbook on modal logic, but Lemmon passed away in 1966, interrupting the project. Scott shared the unfinished work with colleagues, introducing key methods in model theory semantics. These included improving the canonical model, a standard tool in modern Kripke semantics, and using filtrations to build models, both of which remain central concepts today. Scott later published the work as An Introduction to Modal Logic (Lemmon & Scott, 1977).

Stanford, Amsterdam and Princeton, 1963–1972

After Robert Solovay made an initial observation, Scott developed the concept of Boolean-valued models, as Solovay and Petr Vopěnka also did around the same time. In 1967, Scott published a paper titled A Proof of the Independence of the Continuum Hypothesis, in which he used Boolean-valued models to present a different way of analyzing the independence of the continuum hypothesis compared to the method used by Paul Cohen. This work led to Scott receiving the Leroy P. Steele Prize in 1972.

University of Oxford, 1972–1981

In 1972, Scott began working as a Professor of Mathematical Logic on the Philosophy faculty at the University of Oxford. During his time at Oxford, he was affiliated with Merton College and is currently an Honorary Fellow of the college.

During this time, Scott collaborated with Christopher Strachey. Despite challenges from university administration, they worked together to develop a mathematical method for explaining the meaning of programming languages. This work, for which Scott is most well-known, is called the Scott–Strachey approach to denotational semantics. This method is an important contribution to the study of computer science. One of Scott’s key achievements was creating domain theory, which allows programmers to describe the meaning of recursive functions and looping commands in programming languages. Domain theory also helped explain how to understand complex and continuous information.

Scott’s work during this period earned him several awards, including:
• The 1990 Harold Pender Award for using ideas from logic and algebra to develop mathematical meanings for programming languages;
• The 1997 Rolf Schock Prize in logic and philosophy from the Royal Swedish Academy of Sciences for his work in logic, especially the creation of domain theory, which expanded Tarski’s semantic methods to programming languages and helped build models for Curry’s combinatory logic and Church’s lambda calculus;
• The 2001 Bolzano Prize for Merit in the Mathematical Sciences by the Czech Academy of Sciences;
• The 2007 EATCS Award for his contributions to theoretical computer science.

Carnegie Mellon University, 1981–2003

At Carnegie Mellon University, Scott developed a new theory called equilogical spaces as a follow-up to domain theory. One benefit of this theory is that the category of equilogical spaces is a cartesian closed category, while the category of domains is not. In 1994, he was named a Fellow of the Association for Computing Machinery. In 2012, he was named a fellow of the American Mathematical Society.