Conway’s Game of Life has four simple rules:
- Any live cell with fewer than two live neighbours dies, as if caused by underpopulation.
- Any live cell with two or three live neighbours lives on to the next generation.
- Any live cell with more than three live neighbours dies, as if by overpopulation.
- Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.
A naïve look at these rules might indicate that there’s not much going on in this two-dimensional universe. Its four little rules, after all, are quite easy to understand.
Granted, if the initial conditions are random, it doesn’t immediately blow your mind. Even though something is happening, the Game of Life looks more like bacteria flopping around in a petri dish than anything else.
However, if you are more careful with setting up the initial conditions of the game, things can get quite interesting.
How interesting? Well, it turns out that this little universe can host spaceships, guns, racetracks, replicators, and even Bruce Willis. Kind of.
Further, these four rules are — in principle — powerful enough to build a universal computer. You could take these four rules, and with enough careful planning and engineering, you could rebuild your smartphone, laptop, or whatever device you are using to read this article.
Strange, isn’t it?
The thing about simple systems is that they don’t stay simple for long, especially if you scale them up.
A single water molecule might not do too many interesting things. If you put a bunch of them together, however, all sorts of interesting things start happening.
While Conway’s Game of Life is fascinating in its own right, I don’t want to dive too deep into the world of cellular automata. One reason is that this world is practically endless, another reason is that I actually wanted to write about distributed systems and their emergent properties. But hey, moving pixels are fun too, right? (If you do want to take a deep dive into this topic, have a look at the work of Stephen Wolfram and his New Kind of Science.)
The reason these things are fascinating to me is that we keep building systems which might appear simple on the surface, but which keep surprising us.
One could even argue that any given system which has the potential for complex behavior might be “infinitely complex”, meaning that it will behave in a way that is surprising and fundamentally unpredictable. I’ll let you be the judge if this is a good thing or a bad thing.
I guess what I want to say is that you never know what you are dealing with unless the thing you are dealing with is mind-numbingly trivial. I think few things are this trivial.
Conway’s Game of Life illustrates this better than anything else I know.
