The trouble with physics is, that there are too many sacred cows. Things like the Lorentz group, the Equivalence Principle, the Coleman-Mandula Theorem, etc etc etc. It really doesn’t matter what they are, what matters is that they are sacred. They cannot be slaughtered, however much they get in your way and destroy your work. But if you can’t slaughter any sacred cows, how can there be any beef in your theory?
That, of course, is the reason why there is no beef in any theory that is considered at all “reasonable”, in the past 50 years. There is no beef in string theory – it is spaghetti without the bolognese. There is no beef in loop quantum gravity – it is macaroni without the cheese. There is no beef in GUTs – they are tripe without the onions. They don’t predict anything, or if they do, the predictions are not even wrong. There isn’t even any beef in emergent gravity – it is bean sprouts without the soy sauce.
No, if you want beef, you have to slaughter a sacred cow. Which sacred cow do you fancy? For my taste, the Equivalence Principle is ready for the cooking pot. My culinary skills don’t rise to a fillet steak, my beef is usually minced, curried, and/or braised for as long as it takes. But it is beef. My theories make predictions. They do not contradict experiment. If you try my curried beef mince you won’t pronounce it inedible – although it might be surprisingly spicy, and unlike anything you’ve ever tasted before.
It is the unification of different ingredients that is the key to cooking beef: the quanta of spices, the relativity of herbs, the colours and the long slow fusion of flavours of carefully selected vegetables to yield a truly satisfying dish that convinces you that, yes, this is how the world should be.
Of course, it might not be. God might be a vegetarian.
