What Is Pan-Computationalism?

There are robust, strong notions of computation such that, at least on the face of it, most things are not computers. You cannot program or set up any kind of system you want to give your results in a reliable, systematic way. With a digital computer, you can do that with a cactus or a stone, you can't. So I mean, that's a first approximation, but it's just sort of an intuitive example. Hopefully illustrating why there's something wrong with just saying point blank: Yeah, everything performs computations.