\( \renewcommand\vec[1]{\mathbf #1} \newcommand\pp[2]{\frac{\partial #1}{\partial #2}} \newcommand\dd[2]{\frac{\mathrm d #1}{\mathrm d #2}} \newcommand\d{\,\mathrm d} \)

花花花 SuperLaserNino 花花花

home · about · archive · RSS

1/3: Just The Way Things Are

Created: 28 Dec 2015

Modified: 13 Jun 2016

523 words

[Part 1 is about a feeling about the world. Epistemic state: Maybe I shouldn’t commit to writing blog posts about every thought that occurs to me while browsing Wikipedia. Part 2, part 3.]

I decided I don’t like the term “laws of physics” to describe the way reality behaves. Calling them laws makes them sound optional1. Like, it would be really good if you didn’t break them because they are being enforced by the space police, but if you’re really clever, you can outrun the space police and break them anyway. But you can’t.

When you put two marbles down, and then you add two more, the fact that there are now four marbles isn’t a law you can break. It’s not something where some universal authority decides that this should happen by calculating 2+2. It’s just the way things are.

And so, when you hit the accelerator, there is nothing deciding to stop you from going past the speed of light. It’s just not going to happen. Look, for example, at Conway’s Game of Life. Because of the way the game is structured, there is an absolute speed limit and there is nothing you can do to go faster than that maximum speed. And still, if you program a simulation of the Game of Life, you don’t need to add a rule preventing things from exceeding the maximum speed. Like two marbles plus two marbles being four marbles, the speed limit is just a consequence of the structure of the universe.

But! For the people in the Game of Life, it won’t be that obvious, because they don’t see the game board. They see the contents of the cells, but not the cells themselves. So they might wonder why the speed limit exists and they might think they can somehow circumvent it. It’s only when you see the game board that you get an intuitive understanding about why these laws exist and why it’s not forbidden to break them, but a logical impossibility.

This transfers to the real world, too. There have been people who tried to build perpetual motion machines and made plans to go faster than the speed of light and theorized about superluminal neutrinos. Thinking about the laws of the universe as something that logically follows from the stuff the universe runs on, rather than the laws being rules that exist explicitly and are somehow enforced, makes impossible things feel more impossible  – you won’t trick the universe into giving you energy by building a perpetual motion machine that is so complicated that the space police doesn’t notice you’re stealing energy.

I thought that was an interesting intuition.

  1. Weellll, this is arguably inaccurate, but the point is less about the terminology and more about the intuition, so whatev.