The Large Hadron Collider sprung back to life this month, smashing subatomic particles with nearly double the energy used to discover the Higgs boson, a landmark in understanding the makeup of the physical world. With the Higgs now in the bag, researchers are setting their sights on more exotic fare: signs of a new physics that not only describes the universe but explains why it is the way it is.
Four fundamental forces rule reality, but why is the number not three or five or 17? Matter is built from a grab bag of particles whose masses differ so wildly that they appear to have been handed out by a punch-drunk God. The proton weighs 0.9986 as much as the neutron, and each is more than 1,835 times as massive as the electron.
These values, like all the others making up the spec sheet of the universe, seem so arbitrary. Yet if they had been slightly different, theorists tell us, the universe would not have given rise to intelligent life.
Rejecting the possibility that this was nothing more than a lucky accident, physicists have been looking for some underlying principle — a compelling explanation for why everything could only have unfolded in this particular way.
That is not how we ordinarily think of human history, where for the want of a hanging chad we might be living in a very different geopolitical world. With every event, forking paths of possibilities branch out into the future. Pick one of the multitude that didn’t become real, and you might have the plot for a good counterfactual novel.
