Hans Rosling and Raymond Smullyan have died

Why should I worry about dying? It’s not going to happen in my lifetime!

Raymond Smullyan, This Book Needs No Title (1986)

This week, the mathematical community has lost not one but two of its most beloved practitioners. Earlier this week, Swedish statistician Hans Rosling passed away aged 68, and today it’s been announced that author and logician Raymond Smullyan has also died, aged 97.

Hans Rosling: Image from Wikipedia, CC-BY David Shankbone

Hans Rosling was a statistician and doctor, and has appeared in various TV documentaries on statistics, population and global development, as well as being hugely popular in TED talks. He also co-founded the Gapminder foundation, which uses data analysis software Trendalyzer (developed by Rosling’s son Ola) to display and illustrate international statistics in innovative ways.

He’s been awarded many accolades, including being named one of 100 leading global thinkers and one of the 100 most creative people in business. He’s also a member of the Swedish Academy of Sciences and the Swedish Academy of Engineering Sciences, and was instrumental in the establishment of Médecins Sans Frontières in Sweden.

Raymond Smullyan on Carson, 1982 YouTube/betoperdido

Raymond Smullyan was a logician, philosopher and set theorist (and also magician, pianist and puzzle-maker) from New York. He has written books on philosophy, set theory, logic puzzles, Gödel’s incompleteness theorems and even combinatory logic. He is well-known for his ‘Knights and Knaves‘-style logic puzzles, in which you are told that some of the people you’re talking to speak the truth or only tell lies, and you have to work out who is lying based on their statements. The Lady and the Tiger is one famous example, and some incorporate people who only sometimes lie, or lie with a given probability.

Smullyan was a professor of philosophy at Lehman College, City University of New York, and Indiana University. He has published over 30 books, some as recently as last year. On social media, people are honouring his memory by sharing their favourite anecdotes, puzzles, jokes and problems from his oeuvre.

Raymond Smullyan passed away on 6th February aged 97. Hans Rosling died on 7th February at 68, after a year-long battle with pancreatic cancer. They will both be missed by many.