The Wild Improbability of This Moment

It almost certainly would not happen. And yet, here it is.

In this post about Thomas Piketty and the uses of history, I discuss how vast the array of possible futures really is at any given moment in time. The corollary of this is that the future which actually does unfold — which is our present reality — is extremely contingent. And fantastically improbable.

Phil Tetlock and I briefly illustrated a similar point in Superforecasting with a thought experiment dreamed up by the great Daniel Kahneman.

He invites us to consider three leaders whose impact on the 20th century was massive — Hitler, Stalin, and Mao. Each came to power backed by a political movement that would never have accepted a female leader, but each man’s origins can be traced to an unfertilized egg that had a 50% chance of being fertilized by different sperm cells and producing a female zygote that would become a female fetus and finally a female baby. That means there was only a 12.5% chance that all three leaders would be born male, and an 87.5% chance that at least one would be born female. The ripple effects of different results are unknowable but potentially enormous. If Anna Hitler had been born on April 20, 1889, in Braunau am Inn, Austria, World War II might never have happened — or a smarter Nazi dictator might have visited even worse upon us by making shrewder decisions.

I trust you now look like that emoji with the exploding brain.

But here’s a funny thing: That back-of-the-envelope calculation actually overstates the probability of Hitler, Stalin, and Mao all being born male.

After fertilization, an egg must implant in the uterus for a pregnancy to occur. Scientists estimate that between one-third and one-half of fertilized eggs fail to implant. If we take that low figure and apply it to the scenario above, we find the probability of Hitler, Stalin, and Mao all being born boys is … 3.7%.

And even that overstates the probability! Hitler, Stalin, and Mao were all born in the 19th century, when the likelihood of a mother successfully completing a pregnancy and delivering a healthy baby was far lower than now. Factor that in and the tiny probability would shrink further. I don’t have the relevant stats so I can’t make that calculation. But if I very optimistically assume that 90% of pregnancies would be brought to term and result in a successful delivery — I think the real numbers would be lower — it would reduce the probability of Hitler, Stalin, and Mao all being born boys to … 2.6%.

And remember, that’s the probability of Hitler, Stalin, and Mao merely being born as boys. They would still have to survive that first, dangerous year of life. In the 19th century, in most of the world, around one-quarter of infants died. So the probability of Hitler, Stalin, and Mao all being born boys and all surviving their first year of life would be … 1.1%.

And this just gets Hitler, Stalin, and Mao to their first birthdays! They would still be at risk of all the childhood diseases that commonly took children’s lives (cholera, diphtheria, tuberculosis, etc.) as well as all the routine accidents, like being trampled by a horse.

If they survived all that, Hitler, Stalin, and Mao still had to face countless other risks along the way to becoming a history-shaping tyrant — they all encountered major physical dangers on top of the routine dangers anyone faced — and each risk they experienced further reduced the probability that all three would take power.

And on top of all that, there were countless other ways one or all of them could have been diverted to a less homicidal life.

Imagine that one day in 1908, a minor official enjoyed a particularly excellent pastry in a Viennese cafe, strolled to work in a good mood, and decided that maybe he should let that marginal applicant into the Academy of Fine Arts. “What’s his name? Hitler? Maybe he’ll get better. Why not? Give the kid a break. What an excellent pastry that was.”

Adolf Hitler may have spent his life painting bad watercolours for tourists.

In counterfactuals like these ("What if Franz Ferdinand’s driver hadn’t taken that wrong turn?”) the focus is always on Big Names. The reason for that is simple: If Big Names are removed from their known role in history — whether by being born a girl or being kicked in the head by a horse or getting lucky on an art school application — we may not know how history would be different. But we can be certain it would be very different.

But that focus on Big Names can mislead us to think that these wild improbabilities only apply to Big Names. In reality, the same applies to you, me, and all the other Little People. And its importance to the course of history is not limited to Big Names — because, if there’s one thing chaos theory underscores, it’s that Little People matter, too.

To see why, consider the Brad Pitt movie The Curious Case of Benjamin Button.

A running theme in the movie is that small things can make a big difference, which is just another way of expressing the fundamental insight of chaos theory — that even tiny changes in initial conditions can rapidly generate huge changes in outcomes. This is made very explicit in the scene where Pitt visits the love of his life, Daisy, in hospital, after her career as a dancer in Paris has been abruptly ended by an accident.

Pitt’s character intones:

Sometimes we’re on a collision course and we just don’t know it. Whether it’s by accident or by design, there’s not a thing we can do about it.

Pitt then narrates a series of trivial events, involving a host of unrelated people, starting with, “a woman in Paris was on her way to go shopping but she had forgotten her coat. When she had gotten her coat, the phone had rung. She’d stopped to answer it and talked for a couple of minutes. While the woman was on the phone, Daisy was rehearsing for a performance at the Paris Opera House.” Pitt’s character continues narrating, introducing new people and showing how the trivial things one person did led to someone else acting in a certain way, and how that in turn influenced the minor decisions and actions of others. It is a chain reaction of triviality. And it ends in tragedy.

If only one thing had happened differently, if the shoelace hadn’t broken, if the delivery truck had moved moments earlier, or that package had been wrapped and ready, if that girl hadn’t broken up with her boyfriend, or that man had set his alarm and got up five minutes earlier, or that taxi driver hadn’t stopped for a cup of coffee, or that woman had remembered her coat and got into an earlier cab … Daisy and her friend would have crossed the street and the taxi would have driven by.

But life being what it is, a series of intersecting lives and incidents out of anyone’s control, that taxi did not go by and that driver was momentarily distracted and that taxi hit Daisy. And her leg was crushed.

In a world shaped by “a series of intersecting lives and incidents out of anyone’s control,” every single person is capable of making an enormous difference. They may not know when they make a difference. In fact, they almost always will not know they made a difference. But they can and do, simply by living.

So instead of thinking about the colossal figures who defied probability and became history-shaping figures, consider those who did not. Hitler survived the battlefields of the First World War. Were there soldiers who did not survive who would also have become major figures in history — or played a role in the lives of major figures, however remotely — if they had survived? Given that 10 million soldiers were killed, the answer is surely yes. Who they were we’ll never know. How history would have changed we’ll never know. What it would have taken for them to survive we will also never know — but it’s a safe bet that a little luck here or there would have done it.

Maybe if a gust of wind had blown at just the right moment, a French bullet fired in the Battle of Verdun might have strayed just a little and some unknown German soldier would not have died. And maybe that soldier would have still been in uniform on a particularly day in 1923 when he agreed to take a shift for his buddy, and, as a result, he would have been dispatched, not his buddy, when far-right extremists attempted to seize power in Munich. Maybe that soldier would have been a slightly better shot than the man he replaced and the leader of the far-right coup, instead of merely suffering a dislocated shoulder in the mayhem, would have died, along with the 16 other extremists who were killed. And the art school rejectee Adolf Hitler would now be a minor footnote in German history. Because a gust of wind had blown in France at just the right moment.

Or maybe one of ten million other scenarios would have unfolded. We’ll never know.

But here I am imagining events. Pure fiction. So let me close with one final story that is hard fact.

In 1920, two junior American Army officers watched tanks conduct maneuvers. One of the tanks got stuck in mud. A truck was brought to pull it out. A cable was attached, the truck pulled, and the cable snapped and lashed back — almost striking both officers in the head, which would have killed them instantly. The officers were rattled. But they were unharmed. It was a trivial incident involving obscure people who would have been soon forgotten if the truck had parked at a slightly different angle and both men had died.

So why do I even know about this uneventful event? Because one of the officers mentioned it briefly in his diary. And that diary was read by historians — because the two officers were George Patton and Dwight Eisenhower.

I love stories like that. But let’s not forget they are merely the rare, visible manifestations of a phenomenon which is everywhere, always. Our reality truly is “a series of intersecting lives and incidents out of anyone’s control.”