We don’t really have a word for the way reality seems to work.
We have “rules”, but rules were made to be broken (as the saying goes).
We have “laws”, but laws are really just rules enforced by people who scare you. Laws are no more unbreakable than rules.
And indeed, from humanity’s vantage point way up here, there aren’t any absolute rules.
You might think that inanimate objects always fall down until the first time you encounter a helium balloon.
It seems like trees grow up, but you can find trees in caves that grow sideways.
It seems wrong to kill people, but if someone’s trying to kill your family, you might be justified to kill in self defense.
In our towering human world, there’s an exception to every rule. Just ask a lawyer, a judge, or a politician: there is no black and white, there are only shades of gray. If I say “you should never jump off a cliff”, you can say “what if I have a hang glider?”. If I say “always save children from fires”, you can say “what if they’re launching nukes across the street?”
Imagine humanity’s surprise, then, when we first stumbled upon unbreakable rules of reality.
Sir Isaac Newton unveiled one single law that described why apples fall and why the moon goes around the earth.
To fully grasp the revelation, try to empathize with the people of the era, who believed that the heavens followed heavenly laws completely unrelated to our mundane earthly laws.
Then came Newton’s law of gravity, which governed not only the falling of apples but the turning of the tides and the motion of the planets.
It suddenly seemed as if all reality obeyed a single set of laws.
Reflect on that for a moment. It’s always seemed as if reality has rules, because reality has always had order. If something is ordered it can be described. Humans have tried to describe the order of the universe since the dawn of philosophy.
But there was no reason the fundamental laws had to be simple. There was no reason that the heavens had to follow the same laws as the earth. If you push an object on earth it will eventually come to rest on the ground, while the stars above seem to walk their celestial path eternally. Indeed, what laws did we know that were completely without exception? For all we knew, the laws of reality would be like the laws of humanity: wishy washy rules of thumb with wide margins of gray.
The laws that arose from the fundamental rules were certainly complex. Gravity is simple, but the tides are complicated. Chemistry is complicated. Biology is complicated. Why should the rules that govern those rules be simple?
The fundamental rules could have said “Everything follows the rules of gravity, except sometimes when the planets get too close to the sun they get pushed back out again. And then sometimes on every other Tuesday, gravity spikes for a bit, but only near Jupiter.”
They didn’t have to be simple. They could have been complicated.
Then along came Newton, with a few simple rules that governed everything, without exception.
As far as we could tell at the time, the laws of gravity were never violated…
Until we found a violation. Albert Einstein famously discovered that Newton’s law of gravitation is not correct.
What happened next? Did we have to patch up the law of gravity? Did we have to tack on an addendum: “Gravity holds, except on every other Tuesday when a light beam gets too close to the sun”?
No. The fundamental rules got simpler. They got more beautiful. Axioms were removed.
We figured out that the old rules were wrong, but it wasn’t because of an edge case. It wasn’t like human rules, where the exceptions lead you to whole swaths of gray. No, when we violated the laws of gravity we found deeper laws. We found an underlying rule that unified reality even further. We found out that the rules governing the universe are even simpler than we thought.
We found rules that, to our knowledge, have never been violated. Not once. As best we know, the universe has always obeyed general relativity, and it always will.
This seems to be a running theme. Every time we see complexity in our universe, it turns out to flow from simple rules, from rules that humans can understand.
It didn’t have to be this way. The universe didn’t have to be understandable. It didn’t have to follow simple, beautiful rules, and when you get right down to the bottom, maybe it doesn’t.
But so far, everywhere time we’ve turned over a rock or peered out at the stars or jumped head-first into one of the sacred mysteries, it’s turned out to follow fundamentally simple rules. It’s turned out to be beautiful and understandable.
There’s no guarantee that this trend will hold. There’s no guarantee the laws will be simple and there’s no guarantee that we’ll actually be able to understand them. But everywhere we’ve looked so far, the fundamental rules have proved their beauty.
That’s not a guarantee – but it’s a hint.