I'll put it this way: I have no problem imagining a physical system in my head and running a simulation of it, but it is as if instead of receiving the output

I'll put it this way: I have no problem imagining a physical system in my head and running a simulation of it, but it is as if instead of receiving the output of the simulation as images on a screen I am receiving it in the form of instantaneous knowledge of the state of the system. It feels very similar to modelling program state in my head while debugging or whatever.