Control theory defines a control system in a way that covers thermostats and whale-controllers alike. One of the more interesting research topics is figuring out how to make controllers determine the properties of the system they're controlling.

You see this especially in control systems for durable robotics: there are some robots which are designed to determine experimentally what the effects of moving their appendages around will be, and to derive from that a gait that will allow them to walk. If their model of the system later starts failing because they lost a leg or turned into a whale or something, they'll update their idea of what they're controlling. Control systems are surprisingly deep, and damn interesting.

(This is getting way off topic, but in general, loads of things are surprisingly deep if you look at them hard enough. I once found a book on the shelf of a library called "The grain supply of the Roman Empire", and my jaw dropped. Surely, I thought, this must be the most boring book ever written. Obviously, I had to take a look at it. As it turned out, that was a pretty interesting subject. It touched on everything from preventing mold to the tricks used to abuse an ancient welfare system. Go figure.)