Bill Thurston passed away yesterday at the far-too-young age of 65. My thoughts and prayers (for what they’re worth) are with his family.

I never read any of Dr. Thurston’s mathematical work in great detail (geometric topology never really being my thing), but from the popular surveys I read, he was of course brilliant. I can’t really do justice to his mathematical accomplishments, but I’ll quickly say for non-mathematical readers that he was probably best known for his geometrization conjecture, which helped pave the way for the proof last decade of the Poincaré conjecture.

What I *did* read were some of his writings on the philosophy of math; not the boring questions of how “real” mathematical entities are, but thoughts on how we *do* mathematics. I am incredibly grateful that I had the opportunity to let Dr. Thurston know how much those writings meant to me a couple of years ago. It’s nice to think that I contributed, even infinitesimally, to the net happiness in his life.

[ETA: Terry Tao has a much more mathematically complete obituary.]