 When discussing CA as models of reality we need to carefully distinguish the different meanings of modelling.  (CA1)  above  (section 1.2)  discussed CA as “models of computation”: CA model parallel computations in the rather trivial sense that they perform them; for that is what their cells do: they associate inputs to outputs by implementing algorithmic functions, together with their mates. In other words, they model computation as Turing machines do (but, of course, with different underlying ideas). 