A moment ago, I saw the winner of physicist Brian Greene’s “Explain String Theory in Two Minutes” contest. In my current philosophical frame of mind, it got me thinking, and I believe that I’ve realized a fundamental truth about the universe.

I’ll try to explain it as best I can for readers who know little or nothing of physics. I’ll start with some fundamental physical principles:

1. The universe is composed of constituent particles. Every object consists of particles of different sorts, all held together by forces. (Atoms, for example, consist of a nucleus held togehter by the strong nuclear force, and a cloud of orbiting electrons, held to the nucleus by the electromagnetic force).
2. The forces, however, turn out to be the result of the exchange of force-carrying particles. (Think of two people throwing a really heavy ball back and forth: each time the ball is exchanged, it pushes them apart. In the case of attractive forces, think of a rope instead of a ball).

So, the things we call “physical laws,” such as the force of gravity and the strength of the electromagnetic force, are all really just approximations of the result of particles sloshing about. So, in reality, there are no laws of nature. There is only stuff, exchanging particles (which are also stuff) with other stuff.

This worldview seems to take care of a problem that has been irritating physicists for years: Where does time come from? We can’t observe it directly. And what’s more, our physical laws work essentially the same way whether time is running backwards or forwards. Physicists like Julian Barbour have attempted to solve this problem by constructing physical principles that don’t depend on time, but perhaps the only real physical principle is embodied by a tremendous web of particle interactions, unchanging in time because this web is completely timeless.