What is a computation? Intuitively some (say binary) states of the physical world are changed, voltage gates switched, rocks moved around (https://xkcd.com/505/), whatever.
Now, in general if these physical changes were done with some intention like in my CPU or the guy moving the rocks in the xkcd comic, then I think of this as a computation, and consequentially I would care for example about if the computation I performed simulated a conscious entity.

However, surely my or my computer's intention can't be what makes the physical state changes count as a computation. But then how do we get around the slippery slope where everything is computing everything imaginable. There are billions of states I can interpret as 1's and 0's which get transformed in countless different ways every time I stir my coffee. Even worse, in quantum mechanics, the state of a point is given by a potentially infinitely wiggly function. What stops me from interpreting all of this as computation which under some encoding gives rise to countless Boltzmann brain type conscious entities and simulated worlds?