John Horton Conway? Mariana Cook? Alexander Masters? Apocryphal?
Question for Quote Investigator: A prominent mathematician once said something like the following:
Mathematics is simple. Cats are complicated.
Would you please help me to find the correct phrasing and the name of the mathematician?
Reply from Quote Investigator: Channel 4 of the BBC broadcast a series titled “What We Still Don’t Know” in December 2004.1 The third episode was called “Are We Real?”,2 and it featured an appearance by English mathematician John Horton Conway of Princeton University who discussed the cellular automaton game he had invented named Conway’s Game of Life. Conway began with a remark comparing mathematics and cats:3
You know, people think that mathematics is complicated. Mathematics is the simple bit. It’s the stuff we can understand. It’s cats that are complicated. I mean, what is it in those little molecules and stuff that make one cat behave differently to another, or that make a cat? I mean, how do you define a cat? I’ve no idea.
Below are additional selected citations in chronological order.
In 2009 photographer Mariana Cook published the book “Mathematicians: An Outer View of an Inner World” which contained portraits of ninety-two mathematicians together with brief autobiographical texts. John Horton Conway mentioned cats, but he made a different ontological point:4
I still don’t know the sense in which mathematical objects exist, but they do. Of course, it’s hard to say in what sense a cat is there, too, but we know it is, very definitely. Cats have a stubborn reality but maybe numbers are stubborner still. You can’t push a cat in a direction it doesn’t want to go. You can’t do it with a number either.
In 2011 English author Alexander Masters published “Simon: The Genius in My Basement” about the mathematician Simon P. Norton who was Conway’s colleague and occasional co-author. The fifth chapter began with the following quotation:5
You know, people think that mathematics is complicated. Mathematics is the simple bit. It’s the stuff we can understand. It’s . . . cats that are complicated. I mean, what is it in those little molecules and stuff that make one cat behave differently to another, or that make a cat? I mean, how do you define a cat? I’ve no idea.
Professor John Horton Conway,
Simon’s former colleague
In 2015 “The Wall Street Journal” printed a review of a biography of John Horton Conway. The epigraph of the review was the following quotation:6
“People think that mathematics is complicated. Mathematics is the simple bit, it’s the stuff we can understand. It’s cats that are complicated. — John Conway
In conclusion, John Horton Conway deserves credit for this quotation. Conway employed the quotation during a television program broadcast by the BBC in 2004.
Image Notes: Picture of a kitten with a flower from Dimhou at Pixabay. Image has been resized.
Acknowledgement: Great thanks to the anonymous person whose inquiry led QI to formulate this question and perform this exploration.
- 2004 December 4, The Independent, Section: The Information, Sunday Television, December 5, Pick of the Day, Quote Page 52, Column 1, London, England. (Newspapers_com) link ↩︎
- Website: IMDB Internet Movie Database, Series: What We Still Don’t Know, Episode 3: Are We Real?, Host: Martin Rees, Production Company: Darlow Smithson Productions, Airdate: 2004, Website description: Searchable database of information about movies and TV. (Accessed imdb.com on Jun 28, 2026) link ↩︎
- 2004, BBC 4, Series: What We Still Don’t Know, Episode 3: Are We Real?, Chapter 1: in which the cosmologists learn that we were no accident waiting to happen, Remarks by John Horton Conway, Timestamp: 6 minutes 17 seconds of 48 minutes 27 seconds, BBC British Broadcasting Corporation, United Kingdom. (Verified via dailymotion.com) ↩︎
- 2009 December, The New Criterion, Volume 28, Number 4, Still four by Martin Gardner (Book review of “Mathematicians: An Outer View of an Inner World” by Mariana Cook), Note: Excerpt in this journal is reprinted from the book, Start Page 68, Quote Page 70, Column 1, The Foundation for Cultural Review, New York. (Verified with scans) ↩︎
- 2011 Copyright, Simon: The Genius in My Basement by Alexander Masters, Chapter 5, (Chapter epigraph), Quote Page 29, Delacorte Press: A Division of Random House Inc., New York. (Verified with scans) ↩︎
- 2015 August 15, The Wall Street Journal, (Article epigraph), A Fellow of Infinite Jest by Jordan Ellenberg, (Book review of “Genius at Play” by Siobhan Roberts), Quote Page C7, Column 1, New York. (ProQuest) ↩︎