Scott(ID:6953/sco009)

Dana Scott began his education nearly 60 years ago in a one-room schoolhouse
in northern California. At that time, no one could have dreamed he would become
a world-famous scientist, honored by royalty for fundamental advances in an
as-yet-unborn discipline called computer science.

Yet, there he was last month--Carnegie Mellon~s Hillman University Professor
of Computer Science Mathematical Logic and Philosophy--in Stockholm to receive
the 1997 Rolf Schock Prize in logic and philosophy from the Royal Swedish
Academy of Sciences.

Scott was being honored for his fundamental contributions in contemporary
logic and most especially for creating domain theory, a mathematical theory used
for explaining the meaning of advanced computer programming languages. Initiated
in the early 1970s, the work has given scholars the mathematical tools to model
computer programs and predict and analyze what they will do.

"Dana built a bridge between traditional mathematics and the semantics of
programming languages," says Jim Morris, head of the Computer Science Department
in SCS. "He identified a mathematical structure that would correspond to
computer programs and produced a mathematical model for a simple language called
Lambda Calculus. Until he did that, the Lambda Calculus (and all other
programming languages) were understood only through mechanical means. It was as
if our only understanding of conventional calculus was through the formal rules
for differentiation and integration. Dana's models supply the analogues of real
numbers, continuous functions, and the other apparatus that allow one to justify
the formal rules."

"Scott's work completely changed people's thinking about how you'd use math
and logic to reason about computer programs," says SCS associate professor Peter
Lee. "Before domain theory, research into programming languages was pretty
informal--something of a black art. But his work changed the field. The
obligations of researchers to prove their work became mandatory."

From 1963-69, while Scott was at Stanford as an associate professor and
professor of logic and mathematics, the university was just creating its famed
computer science department. "Many people at Stanford were concerned with formal
logic in mathematics, philosophy and linguistics," he recalls. "It was natural
to bring logic to computer science. I was involved with several faculty and
students there in thinking about applications in computer science."

A dramatic turning point in Scott's research career came in the summer of
1969. He attended a workshop in Vienna about a new field of programming language
design and definition. There, he met the late Christopher Strachey, one of the
pioneers in programming languages. A man with outspoken opinions, Strachey's
influence on Scott's thinking was immediate and profound. During a sabbatical
visit to Oxford that fall, Scott began to formulate a precise definition of
denotational semantics within the beginnings of domain theory to carry out
Strachey's conceptually formulated program. "This intense period of work," he
says, "influenced the whole rest of my academic life."

But Scott insists that he himself was not a pioneer. "I'm an organizer of
ideas and solver of mathematical problems," he says. "Other people were chopping
down trees, and I was busy building them into log cabins."

In late 1969, Scott delivered three public lectures on his new approach.
According to Peter Lee, they stunned the theoretical computer science community.
People spent years trying to comprehend them and their consequences fully. Today
Scott is revisiting domain theory and trying to make the material more
accessible.

SCS professor John Reynolds remembers being in the audience at Oxford for
Scott's second lecture. "It had a life-long impact on my own research," he
remarks. "Dana introduced a new way to describe programming languages that was
far more expressive and flexible than anything known before. In a deep sense, he
showed how to say what a language meant, rather than just how it might be
implemented on a computer."

Scott says Reynolds and many other researchers have made many contributions
to and applications of the theory. And the work continues at many centers of
research. Even today, Scott himself is revisiting the ideas and trying to make
the material more accessible and usable.