The New York Times is running an article about one quirky explanation for why we haven’t found a Higgs boson yet.
A pair of otherwise distinguished physicists [Holger Bech Nielsen and Masao Ninomiya] have suggested that the hypothesized Higgs boson, which physicists hope to produce with the collider, might be so abhorrent to nature that its creation would ripple backward through time and stop the collider before it could make one, like a time traveler who goes back in time to kill his grandfather.
The picture should be familiar enough from Lewis’s discussion of time travel. What would happen in a time travel world if someone tried to go back in time to kill their grandfather? They’d fail. They might fail in surprising ways. At this point of the story banana peels start to play a prominent role, leading to one of the better paper titles of our time.
But as Nielsen acknowledges in the article, it isn’t quite so clear why creating the Higgs boson would be akin to killing one’s grandfather. And at this point the analogy with time travel starts to look strained.
If we’re doing speculative physics on the basis of Lewisian philosophy, I think we should be looking not at Lewis on time travel, but Lewis on QM. In How Many Lives has Schrödinger’s Cat?, Lewis discusses what it feels like to be the inhabitant of a world where the Everett Hypothesis is true. And his conclusion is that inhabitants of such a world will appear to have, from their perspective, a surprising number of near-death experiences.
The picture is that whenever we get near to death, there’s a possible evolution of the world in which we don’t die. (That tumour quantum tunnels its way out of the patient’s body, etc.) Now from an external perspective, such bizarre possibilities are generally ignorable quirks. But from the perspective of the agent nearing death, things look quite different. They don’t experience anything after they die. So all of the possibilities in which they keep experiencing are ones in which they survive. So if the only way to survive a time period t is through a series of events that are incredibly improbable, all of the agent’s future experiences will be in worlds where those events happen. So despite the improbability, the agent should expect those events to happen, in the sense that those events will probably be part of the only future the agent knows.
Now suppose that creating a Higgs boson (or more precisely isolating one) will lead to the instantaneous destruction of the universe. (Actually we just need that it leads to the death of everyone on earth.) And suppose the Everett hypothesis is true. Then unless the creation of a Higgs boson has probability 1, there are some really existing futures in which the Higgs is not created. And we should expect (with probability 1) that we’ll find ourselves in one of them. So we should expect (with probability 1) that the attempt to create a Higgs boson will appear to fail.
If future attempts to create a Higgs boson fail in more and more unlikely ways, I think we’ll have to start taking this hypothesis seriously. So far we’ve had two attempts to create the Higgs boson fail in mildly surprising ways. I think we need to get to more like 8-10 failures before we start worrying about the hypotheses sketched here, but if the improbable failures start accumulating, the lessons of How Many Lives has Schrödinger’s Cat? start to look more and more pressing.
Hopefully they’ll get the LHC back working soon and we can put crazy ideas like these to bed!