The ultimate goal of physics is to accurately describe, as precisely as possible, exactly how every physical system that can exist in our Universe will behave. The laws of physics need to apply universally: the same rules must work for all particles and fields in all locations and at all times. They must be good enough so that, no matter what conditions exist or what experiments we perform, our theoretical predictions match, or at least are consistent with, the measured outcomes. And having predictive power, explicitly, means that if you know the initial conditions of your system and the laws that govern it, you can predict what the outcomes — or the relative probability of the set of possible outcomes — will always turn out to be. The most successful physical theories of all fall into two separate categories: the quantum field theories that describe each of the fundamental interactions (electromagnetic, weak nuclear, and strong nuclear) that occur between particles, as well as General Relativity, which describes spacetime and gravitation. And yet, there’s one fundamental, …