Transcript

Complexity. It sounds very sciencey, doesn't it? Everyone loves to talk about complex problems and complex systems, but no one has any idea what it means. I think that understanding complexity is the biggest gap in science today. What do we even mean by complexity? What do we know about it, and what's the problem with trying to explain it. That's what we'll talk about today.

How complex Do you think these objects are? A rock, a clockwork, a baby? I'm guessing most of you would rate the baby the most complex, the clockwork somewhere in the middle, and the rock the least complex unless possibly you're a geologist working on a grant proposal, in which case you probably shouldn't be watching YouTube. But why? I mean, babies aren't all that difficult, are they? Stuff goes in one end and comes out the other, and for the first couple of months, that's pretty much it. Okay, you might say, but they grow, they learn to speak, they go on and win Nobel prizes. Sometimes clockworks don't do that. The baby is more complex, not because of what it does, but what it could go on to do. How can we possibly scientifically capture property like that? Maybe, let's start with a simpler example, coffee, or if you're British, imagine it's tea, and we pour milk into it. Initially you have the coffee and the milk separated. That's very orderly, very non complex. Then you mix them together, and well, some complex things happen. Then it's completely mixed. And that's maximum entropy and non orderly again. So complexity is somewhere in the middle between the two, between strict order and maximum disorder, between very low and very high entropy. This isn't just the case for latte. It's also the case for the entire universe.