I’ve never purchased a lottery ticket, which I’m pretty sure is why I’ve never won. Lotteries are of course examples of zero sum games (or even worse than zero sum, since the state’s not running the lottery just for something to do – they’re making money!) However, some people have pointed out that if many worlds is true, you have a sure-fire way of winning the lottery.

First, build a suicide machine.

Next, go buy a lottery ticket. A single ticket will do just fine.

Now set up the suicide machine so that it will kill you in your sleep if you don’t win.

Go to sleep (sweet dreams!)

If you wake up (as, according to many worlds, you must in some history), then you’ve won the lottery!

Sounds pretty grim, but the idea comes from the fact that every possible outcome must happen in some history, so that somewhere your lottery ticket is the lucky one. And since any “you” that results from the many worlds splitting is in fact you, then you’ve just guaranteed yourself a big payoff.

The problem, of course, is that in the vast majority of histories you’ll be dead. Maybe you don’t care, but I might. I kinda like you, and chances are that in my history your infernal machine just snuffed you out. So don’t do it!

It sounds like a sick joke, sort of Schrodinger’s cat meets The Hunger Games , but such ideas are the topics of serious conversation in the many worlds debate.

Another version says that in some history I will live forever. In another history you will, too. In a vanishingly percentage of histories, we both will, but they’re so rare that we’ll ignore them for now. Here’s the idea. When I get to a potentially life-ending event (as I must every moment of every day), I will always find myself in the history in which I survive. Since there’s always some history in which I survive anything, I will live forever. Even as I grow old and grey (ok, older and greyer), something happens that causes my continued existence. I’ll notice the rest of the world passing by as normal, but I will find myself becoming the oldest living human, first by just a little, then by a decade, then a century, and so on.

I doubt this. For one thing, it seems to require either cause-effect problems or else historical discontinuities. For instance, I may be hit by a cosmic ray today that will start a slow cancer. The cancer might kill me in, say, ten years. So ten years from now in this history I’m ready to die, but somehow I don’t. Maybe I just barely survive. OK, fine.

But what about this? Right now there is an asteroid in deep space that, with the right nudge, could find itself on a collision course with the Earth. This is no ordinary Cretaceous Era asteroid that will wipe out 90% of life on the planet. No, this is a world-shattering asteroid that will turn the Earth itself into a pile of rubble. It is unfathomable that I could survive such a cataclysm. But how does my current history know to avoid the branch in which that asteroid tumbles Earthward? If you don’t think the asteroid is final enough, consider nearby supernovas, or disasters that destroy the Sun itself.

Or what about this? I hold a gun to my head and fire. In the fraction of a second after the bullet starts to move, but before it enters my brain, I’m still conscious. I’m still in that universe where a bullet is flying toward me but I’m alive. How in that history do I avoid death? And when exactly does the death avoidance happen?

Still, maybe there is some utterly unlikely way to survive. I suppose the test is this – if I find myself in situations again and again where I should die but don’t, then the hypothesis of quantum immortality is supported. Of course, if that doesn’t happen, I’ll never know about it, now will I?

But here’s another point. None of us live in such a universe, where some really old guy is living out his quantum immortality history. Yet if I were such a person living forever, I’d be surrounded by younger people who would see my odd immortal state. But who would those people be? What if (OK, this is really getting into the realm of fantasy now) they were actually my children? If not for my odd immortality, they would never exist. So they would only know a universe in which the reality of quantum immortality was manifest. Yet none of us, alive in this universe, can know this. So I ask again, who are these people? Another way of looking at it is, why aren’t we living in a universe where one, two, or more people are immortal?

All this assumes, of course, that there’s something special about consciousness. I’m not sure that’s a justified assumption, and neither does David Deutsch:

“There is the so-called ‘quantum suicide argument’ in regard to the multiverse . . . However, that way of applying probabilities does not follow directly from quantum theory . . . It requires an additional assumption, namely that when making decisions one should ignore the histories in which the decision-maker is absent . . . the theory of probability for such cases is not well understood, but my guess is that the assumption is false.”

So go buy a lottery ticket if you must, but as for your quantum suicide machine, don’t do it!

For the last entry in this series on many worlds, I’ll revisit a topic I’ve written about before, the reality of free will.