I read an abridged version of this at the conclusion of Petrov Day in Boston this year.

This year, Petrov Day is a more solemn occasion than usual. Last week, it became known to us that our holiday’s namesake, Stanislav Petrov, has died. (His death was actually on May 19, but the news went unreported until last week—a testament to the obscurity he lived his life in.)

We don’t have a eulogy for Petrov, because we didn’t know much about him as a person. There was a documentary about him in 2014, but you do not come to know a man by watching a documentary. And yet, our community has built a shared myth around him, and around the events of that fateful night—a myth of big red buttons and impossibly high-stakes decisions and the salvation of humanity from nuclear annihilation.

Given the well-known danger of myths and stories to rational thought, one might well ask whether this is wise. Why do we do it?

We do this because it matters who we choose to remember.

Stanislav Petrov is one of a very few people who can be credited, on expectation, with saving billions of lives. He may have been the last living person to have earned that distinction. Others include Vasili Arkhipov, whose name was mentioned earlier; Norman Borlaug, father of the Green Revolution that averted global mass starvation as the world’s population exploded; Fritz Haber and Carl Bosch, who invented the means to mass-produce ammonia for fertilizer which feeds half the people alive today; and Karl Landsteiner, Albert Hustin, Luis Agote, and Richard Lewisohn, whose discoveries made blood transfusion possible.

This isn’t a list of saints. Haber, for one, is also remembered as the father of chemical warfare. And for all the importance of their actions, they were still only human, with greater or lesser personal flaws just like anyone else. But they saved the world.

In Petrov’s case, when the universe handed him an encounter with X-risk, he had the expertise and strength of rationality to know what was the right thing to do, and the courage and integrity to actually do it.

We choose to remember Stanislav Petrov so that, if the day should come when one of us is called upon to do the right thing in a situation of truly great import, we might find it within us to do as he did.

Let us take a moment of silence, to honor the memory of a man now lost to us forever, whose life, like any other, was beyond measure—and who, by being the right man in the right place at the right time, saved us all.