Von Neumann

Von Neumann is the clearest case in this course of a Hungarian-born mind whose ideas shape everyday life, since the computer on which you are reading this is built on a design that still bears his name. He is also a case where "who invented it?" has no single answer. This chapter follows his path from Budapest to Princeton, describes his main ideas in plain terms, and treats the credit dispute and the controversies around his later career with care. Names, dates and details are from general knowledge and flagged for checking.

A Budapest Prodigy

He was born Neumann János Lajos in Budapest in 1903 into a wealthy Jewish banking family (check the details), and became known in his youth for extraordinary memory and quickness with numbers (check the stories, many of which are anecdotes). He attended the Lutheran gymnasium in Budapest, the same school as Eugene Wigner (check), and studied mathematics at Budapest while also taking a chemical engineering degree in Zürich (check). He took a doctorate in mathematics in Budapest in 1926 (check). His family had been ennobled and the name became "von Neumann" in German-speaking academia (check).

Mathematics and Physics

In the 1920s he worked in Göttingen, then a centre of mathematics, and in Berlin and Hamburg (check). His early work included:

• Set theory. A rigorous way to define the foundations of mathematics (check the details).
• Quantum mechanics. A mathematical framework for the theory in terms of operators on a space of states, set out in a book of 1932 (check).
• Game theory. A proof in 1928 that in a certain kind of two-player contest there is a best strategy (the minimax theorem), later developed in a book with Oskar Morgenstern in 1944 (check). It is the basis of much of modern economics.

He moved to the United States in the early 1930s, joining the Institute for Advanced Study at Princeton, where Einstein was also based (check the dates). As in Chapter 8, the move came as political conditions in central Europe worsened.

The Computer Design

In the 1940s von Neumann became involved with early electronic computers. The earliest machines were programmed by changing wiring and switches by hand. In 1945 he wrote a draft report on a proposed machine (the EDVAC) in which the instructions, like the data, were stored in the computer's memory (check the title and details). This is the stored-program idea, and the arrangement of a processing unit, a memory and input and output is called the von Neumann architecture.

War and Weapons

During the Second World War von Neumann worked as a consultant on military and scientific projects, including the Manhattan Project at Los Alamos, where he contributed to the design of the implosion method for the plutonium bomb (check the details of his role) and used early computers for calculations. After the war he advised on nuclear weapons and defence policy, and served on the Atomic Energy Commission from 1955 (check). The ethics of this work are debated, and some remarks attributed to him about the Cold War are reported second-hand (check). The course describes the work and does not take a side.

Other Ideas

• Monte Carlo methods. Using random sampling to solve problems, developed with others at Los Alamos (check).
• Self-reproducing machines. A theoretical study of automata that can copy themselves, which anticipated ideas in biology and computing (check).
• Weather and numerical forecasting. Early computer work on weather prediction (check).

He died in Washington in 1957 at the age of 53 (check), of cancer. His later years are remembered for the range of his work and for the number of fields that took ideas from him.

Exercises