## The 2022 Thoralf Skolem Memorial Lecture

published: 2022-11-12

event date:
2022-12-08

*Harry Lewis, Gordon McKay Research Professor of Computer Science at Harvard University*

The Birth of Binary: Leibniz and the Origins of Computer Arithmetic

The curious history of the binary number system includes a multimillennial prehistory and a few early seventeenth-century sparks that did not catch fire. Though several others independently came up with the binary system, my recent translation and edition (with British intellectual historian Lloyd Strickland) of mostly unpublished works on binary by Gottfried Wilhelm Leibniz (1646–1716) establishes Leibniz as the key progenitor of the arithmetic used in today’s communications and computing technologies. I will review Leibniz’s research on binary notation, his increasingly sophisticated algorithms for binary arithmetic, his development of some rudiments of Boolean algebra to describe his calculus symbolically, his improvisation of a concatenation semigroup to describe patterns in bit strings, his plans for two different binary calculators, and his invention of what we now call hexadecimal notation, complete with four different notations for the hex digits, including the one in general use today. I will also comment on Leibniz’s efforts to universalize his invention by connecting it to Christian and Chinese traditions.

*Harry Lewis, Gordon McKay Research Professor of Computer Science at Harvard
University, holds AB and PhD degrees in Applied Mathematics from Harvard. A
member of the Harvard faculty since 1974, he has helped launch thousands of
Harvard undergraduates, including both Bill Gates and Mark Zuckerberg, into
careers in computer science. Principal architect of Harvard’s undergraduate
computer science program, he served as Dean of Harvard College and interim dean
of Harvard’s Engineering School and was the recipient of the IEEE’s 2021 Mary
Kenneth Keller Computer Science & Engineering Undergraduate Teaching Award. His
recent books include an edited collection of classic computer science papers,
“Ideas that Created the Future,” as well as “Leibniz on Binary” with Lloyd
Strickland, both published by MIT Press.*

*Time and place: December 8, 2022, 13:15 –15:00, Georg Sverdrups hus
(Universitetsbiblioteket), Blindern, Auditorium 1.*

It will be possible to follow the lecture on Zoom:

https://uio.zoom.us/j/63956167845

Fore more on the Skolem Lecture, see

https://www.hf.uio.no/ifikk/english/research/groups/logic/events/