Hugh Everett鈥檚 many-worlds interpretation of quantum mechanics arose from what must have been the most world-changing drinking session of all time. One evening in 1954, in a student hall at Princeton University, grad student Everett was drinking sherry with his friends when he came up with the idea that quantum effects cause the universe to constantly split.
Read more: 鈥�Multiverse me: Should I care about my other selves?鈥�
He developed the idea for his PhD thesis 鈥� and the theory held up. According to his work, we are living in a multiverse of countless universes, full of copies of each of us. It was sensational.
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of Massachusetts Institute of Technology has said that Everett鈥檚 work is as important as Einstein鈥檚 work on relativity. But the leading physicists of the Everett鈥檚 day, in particular Niels Bohr, one of the fathers of quantum mechanics, couldn鈥檛 stomach it. They couldn鈥檛 cope with the idea that every decision we make creates new universes, one for all possible outcomes. Everett had to publish a watered-down version of his idea. Thoroughly disgruntled, he left physics.
What he did next fascinates me, in the light of what he had discovered. Everett joined the Pentagon, and worked in a team calculating potential deaths in the event of nuclear war. His job was to calculate how to maximise the death toll for the Soviets while minimising it for Americans by looking at fallout.
If the many-worlds view is right, our actions shape our counterparts鈥� lives in parallel worlds. What does this mean for how should we behave in this world? It鈥檚 a question I explore 鈥� with the help of leading physicists, as well as Hugh Everett鈥檚 rock star son 鈥� in this in-depth article: 鈥�Multiverse me: Should I care about my other selves?鈥�.
Mutually assured destruction
But what about Everett himself? Did he consider what working for the Pentagon would mean in parallel worlds? Wasn鈥檛 he facilitating nuclear war in the multiverse? We can鈥檛 ask him, because he died in 1982, aged only 51. But we can ask those who know his work.
鈥淗e wrote arguably the first ever serious report on just how devastating a nuclear war would be for the US,鈥� says Tegmark. It helped devise the concept of mutually assured destruction (MAD). This is a concept appropriately summed up by its acronym 鈥� in that we鈥檇 be insane to start a nuclear war 鈥� but MAD might actually have prevented the cold war from overheating.
鈥淢AD might have in a major way contributed to the extra caution that might explain why we鈥檙e still here,鈥� says Tegmark. 鈥淢y guess is that Everett鈥檚 work helped drive home the full horror of war, and this reduced the fraction of the multiverse that saw global nuclear war.鈥�
The work Everett did for the Pentagon, then, arguably had a net positive effect on the multiverse. It鈥檚 tempting to speculate that these actions were influenced by his physics work, but we鈥檒l never know.
Unstoppable vs immovable
Everett鈥檚 life was fascinating and tragic. Peter Byrne鈥檚 book, provides a detailed account. Many moments stand out, here are a few.
Everett wrote to Einstein when he was 12 鈥� and Einstein replied. Young Hugh was already keen at challenging the very highest figures of physics authority. His letter was an attempt to solve the paradox of what happens when an unstoppable force meets an immovable object.
He was recommended for Princeton by his old professor of mathematics, who wrote, 鈥淭his is a once-in-a-lifetime recommendation for I think it most unlikely that I shall ever again encounter a student I can give such complete and unreserved support.鈥�
When Everett died of a heart attack, his teenage son Mark discovered the body. Mark recalls that trying to revive his dead father was the first time he could remember ever touching him.
Everett was a keen atheist. Following his instructions his widow, Nancy, threw his ashes out with the garbage.
Everett鈥檚 son Mark referenced his father in a 2005 song :
I never really understood what it must have been like for him,
Living inside his head,
I feel like he鈥檚 here with me now,
Even though he鈥檚 dead.
There is also , and an award-winning .
