Alan Lightman (MS ’73, PhD ’74, DAA ’03) wrote his Caltech thesis on accretion disks and gravitation theory under Kip Thorne. In 1993, he published Einstein’s Dreams, and at MIT he became the first person to hold faculty appointments in both the sciences and the humanities. He received a Distinguished Alumni Award in 2003 and spent that spring back on campus as writer-in-residence, giving a seminar in Baxter Hall titled “The Physicist as Novelist.”
His essay in a recent issue of The Atlantic argues that existence is improbable enough to be worth noticing, and it argues the point the way a physicist would: by running the numbers. Each conception draws on about 300,000 eggs and some 300 million sperm, which works out to roughly a hundred thousand billion possible DNA combinations. One of them produced the person reading this sentence. To make that fraction visible, he pictures a ruler stretching from here to Pluto. One inch of it is you. The rest is everyone who could have been and never was.
The essay ends on gratitude. Lightman keeps a poster above his desk holding photographs of roughly two dozen mentors, parents and teachers and colleagues, some of them now gone, and looks up at it each day. He rules out the universe, which he notes has no mind, and the people who never existed, since he can hardly owe anything to those who aren’t here. What remains is a responsibility to himself, “to not waste my precious life.”
Read the essay in The Atlantic, or a shorter version, posted on Lightman’s Substack.