Computer Science

The field called computer science was born in the 1940s, though its roots extend back to the nineteenth century and even earlier. One of the early founders of the field was Alan Turing (1912–1954), a citizen of Great Britain, who in 1937 published his famous paper entitled "On Computable Numbers with an Application to the Entscheidungsproblem." In this paper he introduced the concept of an abstract computing device, later dubbed a Turing machine. It was precisely the simplicity of his model that permitted scientists to ask, and answer, fundamental questions about the nature of computation. Any computer can be simulated by a Turing machine, and the converse is also true. Moreover, the complexity of Turing machine computations yields insights into the efficiency of computations on real computers. Two other famous mathematical logicians who made early contributions to computer science were Alonzo Church (1903–1995) and Kurt Gödel (1906–1978). Church developed a system called the lambda calculus, which makes possible logically precise expressions of mathematical propositions. The lambda calculus proved to be a model for functional programming, and the popular LISP programming language used the lambda calculus as its theoretical base. Of equal import was the so-called Church thesis, which states that every effectively calculable number-theoretic function is lambda-definable. The importance of this result is that it ties numerical computation to string manipulation, an initially surprising result. Kurt Gödel is best known for his proof of "Gödel's Incompleteness Theorems." As early as 1931 he proved fundamental results about axiomatic systems, showing that in any axiomatic mathematical system there are propositions that cannot be proved or disproved within the axioms of the system. In particular the consistency of the axioms cannot be proved.

Computer science was not founded solely by mathematicians. An equally important group was electrical engineers, who focused on actually building a computing machine. World War II identified and spurred a need for computing devices, machines that could help carry on the mechanics of war. Enlisted into this cause were some of the greatest scientists of the day. One of these was Howard Aiken (1900–1973), who in 1944 built the Automatic Sequence Control Calculator (Mark I) at Harvard University. Another groundbreaking effort was the development of the ENIAC computer by John Mauchly and John Presper Eckert at the Moore School of Electrical Engineering of the University of Pennsylvania. Mauchly and Eckert were in turn influenced by John Vincent Atanasoff (1903–1995), who is now widely recognized as the inventor of the world's first electronic computer, the so-called Atanasoff-Berry computer (ABC machine). The ABC machine employed all of the basic units of a modern digital computer, including binary arithmetic, a separate arithmetic unit, and vacuum tubes for emulating logical switching circuits such as adders. The mathematician-turned-computer-scientist John von Neumann (1903–1957) worked closely with Mauchly and Eckert, and among many results he is usually credited with the idea of the stored program computer, the idea that a computer would contain within it both a program for processing the data as well as the data itself.