Things a Computer Scientist Rarely Talks About

by Donald E. Knuth (Stanford, California: Center for the Study of Language and Information, 2001), xi+257 pp.
(CSLI Lecture Notes, no. 136.)
ISBN 1-57586-327-8
Japanese translation by Tooru Takizawa, Yuko Makino, and Noboru Tomizawa, Computer Kagakusha ga Mettanî Kataranaî Koto (Tokyo: SiBaccess Co. Ltd, 2003), x+260 pp.

In the fall of 1999, computer scientist Donald E. Knuth was invited to give six public lectures at MIT on the general subject of relations between faith and science. The lectures were broadcast live on the Internet and watched regularly by tens of thousands of people around the world, and they have remained popular many months after the event. This book contains transcripts of those lectures, edited and annotated by the author.

After an introductory first session, the second lecture focuses on the interaction of randomization and religion, since randomization has become a key area of scientific interest during the past few decades. The third lecture considers questions of language translation, with many examples drawn from the author’s experiments in which random verses of the Bible were analyzed in depth. The fourth one deals with art and aesthetics; it illustrates several ways in which beautiful presentations can greatly deepen our perception of difficult concepts. The fifth lecture discusses what the author learned from the “3:16 project,” a personal exploration of Biblical literature which he regards as a turning point in his own life.

The sixth and final lecture, “God and Computer Science,” is largely independent of the other five. It deals with several new perspectives by which concepts of computer science help to shed light on many ancient and difficult questions previously addressed by scientists in other fields.

A significant part of each lecture is devoted to spontaneous questions from the audience and the speaker’s impromptu responses, transcribed from videotapes of the original sessions.

The book concludes with a transcript of a panel discussion in which Knuth joins several other prominent computer specialists to discuss “Creativity, Spirituality, and Computer Science.” The other panelists are Guy L. Steele Jr. of Sun Microsystems, Manuela Veloso of Carnegie Mellon University, and Mitch Kapor of Lotus Development Corporation, together with moderator Harry Lewis of Harvard University.

The author has contributed additional notes and a comprehensive index. More than 100 illustrations accompany the text.

Excerpt from the Foreword by Anne Foerst

Many listeners, particularly students, used the opportunity to ask their “god” about the questions that bothered them. Don had to address questions such as, “Why is there evil in the world?” “What happens after death?” Students wanted him to give them answers about the meaning of life, and if there were any miracles. In short, they treated Don as people within a faith-community treat their minister.
It didn't help that Don was absolutely clear about having no authority to answer these questions. It was particularly upsetting for some people when Don gave his opinion that the questions have no objective, universally valuable, and applicable answers; that everyone has to try to seek answers for themselves. From the feedback, I gathered that some people were disappointed. But the vast majority of people were excited. Against all of their prejudices, here was someone religious who did not claim to own the truth. Instead, Don invited his listeners to find their own path, of questioning and reasoning about themselves and all the rest.
The text of this book certainly speaks for itself. I would like to invite the reader to follow the quest within this book. It was an exciting event at MIT, and I am convinced that the book can get much of the same spirit across. I wish the reader fun, anger, excitement, and trouble, because that is something only a deeply engaging topic such as religion and science can do for us. Don has presented a wonderful way to relate his science and his faith, and I hope the readers will enjoy it as much as the live audience did.

Other Reviews

Things a Computer Scientist Rarely Talks About is a unique book. Ultimately its charm lies in the author’s approach to the subject rather than what he actually finds in the end. As Knuth himself writes, in discussing the purpose of life, “The important thing to me ... is not the destination, but the journey.” -- Saul A. Teukolsky, Physics Today (April 2002)
One mark of a good author is the ability to make a successful book out of an unpromising subject. -- American Scientist (May--June 2002)
... a fascinating book. ... musings about the interface between computer science and Christian theology are definitely not what one usually hears computer scientists talking about, but I'm glad Knuth was willing to take the risk of discussing them. -- Fernando Q. Gouvêa, MAA Reviews (February 2002)
Lecture 6 was the meat of the book for me, discussing how concepts of computer science including computational complexity might give insights about divinity. -- Ian Parberry, SIGACT News (December 2002)
Although there is little technical content ..., this collection of wisdom and insights makes fascinating reading ... After all, the author says, “computer science is wonderful but it is not everything.” Occasionally even mathematicians and computer scientists should think about the meaning of life. ... Each chapter concludes with a really good set of spontaneous questions from the audience and the speaker’s impromptu responses, as well as excellent endnotes. -- Jerrold W. Grossman, Mathematical Reviews (November 2003)
Knuth’s involvement was a great boon for MIT’s “God and Computers” project. -- Albert C. Lewis, Zentralblatt MATH 1033 (2004)
... Knuth is courageously unconventional, dealing with theological matters as a mathematician and computer scientist. It’s always reassuring, and even inspirational, to see a famous scientist humbly approach these questions and declare himself confused like the rest of us. ... [The book’s] value is in seeing that computer scientists can and should address the big issues; and also the uniquely humorous, down-to-earth, and personal way that he does it. After all, he opens with, “Why I am unqualified to give these lectures” and then “Why the lectures might be interesting anyway.” And they certainly are.
-- Brendan O’Connor, IEEE Annals of the History of Computing (October--December 2004).

Further notes

This book can be ordered from the publisher (CSLI), and also from the distributor (University of Chicago Press).

Curiosity seekers might also want to go back to the old (1999) webpage on which the lectures were first advertised.

Videos of the original lectures were hosted for many years by Dr Dobbs Journal, but all traces of those videos seem to have disappeared. Audio files do survive, however, thanks to Udo Wermuth:

lecture 1 (6 October 1999]
lecture 2 (13 October 1999]
lecture 3 (27 October 1999]
lecture 4 (3 November 1999]
lecture 5 (1 December 1999]
lecture 6 (8 December 1999]
panel discussion (17 November 1999]


As usual, I promise to deposit a reward of 0x$1.00 ($2.56) to the account of the first person who finds and reports anything that remains technically, historically, typographically, or politically incorrect. If you have the original hardback edition of 2001, you might be interested in its historic errata list, which enriched the coffers of numerous readers.

Here is a list of all nits that have been picked so far in the first paperback printing (2003):

page vii, line 7 from the bottom (30 Dec 2020)
change "Stephen" to "Steven"
page 6, line 5 (14 Nov 2003)
change "in a effort" to "in an effort"
page 13, line 15 (31 May 2023)
change "Institute of Technology" to "Mellon University"
page 23, line 14 (25 Mar 2011)
change "ton, Rouge" to "ton Rouge"
page 35, bottom line (30 Oct 2010)
change "on every" to "on nearly every"
page 36, line 2 (30 Oct 2010)
change "59 pages" to "roughly 59 pages"
page 112, line 1 (18 Nov 2003)
change "Kirsten" to "Kerstin"
page 120, lines 10, 11, 12 (02 Feb 2017)
change "mirror image ... didn't fit" to "rotation. When I first prepared this image, my combination of the individual layers and color separations was slightly off; the letters didn't fit"
page 125, lines 4 and 5 from the bottom (13 Apr 2021)
change "David had stolen Michal away from her husband" to "David had reclaimed his first wife, Michal, from her current husband, a victim of circumstances."
page 134, line 10 from the bottom (29 Dec 2003)
change "Page 96" to "Page 95"
page 135, line 18 (25 Jul 2011)
change "van Randow" to "von Randow"
page 165, line 6 from the bottom (21 Nov 2003)
change "the the" to "the"
page 200, line 16 (27 Nov 2007)
change "Job 33" to "Job 22"
page 204, replacement for line 9 from the bottom (11 April 2022)
2:9, 2:17, 3:3. This tree was “in the midst of the garden.”
page 228, line 20 (25 Jan 2007)
change "is to ask is" to "is to ask"
page 237, line 15 (25 Mar 2011)
change "Baton, Rouge" to "Baton Rouge"
page 243, Cantor entry (26 Jun 2005)
change "Philip" to "Philipp"
page 245, Dijkstra entry (28 Mar 2005)
change "Wijbe" to "Wybe"
page 245, Drosnin entry (10 Oct 2022)
change "Michael" to "Michael Alan"
page 247, Hart entry (10 Oct 2022)
change "Johhny" to "John Lewis"
page 249, Lotus entry (10 Oct 2022)
change page 3 to page 4
page 252, Planck entry (28 Apr 2008)
change "Max Karl Ernst" to "Karl Ernst Ludwig Marx (= Max)"
page 253, Randow entry (25 Jul 2011)
change "van" to "von"
page 256, Van Randow entry (25 Jul 2011)
change it to "von Randow", and re-alphabetize
page 256, Ventura entry (10 Oct 2022)
change "Jesse" to "Jesse (= Janos, James George)"
back cover, line 15 (25 Jun 2015)
change "translation,aesthetics" to "translation, æsthetics"

I hope the book is otherwise error-free; but (sigh) it probably isn't, because each page presented me with numerous opportunities to make mistakes. Please send suggested corrections to, or send snail mail to Prof. D. Knuth, Computer Science Department, Gates Building 1B, Stanford University, Stanford, CA 94305-9015 USA. I may not be able to read your message until many months have gone by, because I'm working intensively on The Art of Computer Programming. However, I promise to reply in due time.

DO NOT SEND EMAIL TO KNUTH-BUG EXCEPT TO REPORT ERRORS IN BOOKS! And if you do report an error via email, please do not include attachments of any kind; your message should be readable on brand-X operating systems for all values of X.

Don Knuth’s home page

Don Knuth’s book on the 3:16 project

Don Knuth’s other books

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