 Although some CA topics are still relatively untouched by philosophers (e.g., the nature of space and time (see Wolfram 2002: 481–496), the representation of knowledge in Artificial Intelligence (see Berto, Rossi, Tagliabue: 15–26), the relationship between information and energy (see Fredkin &amp; Toffoli 1982)), there are many conceptual challenges raised in connection with CA. While in some cases the CA contribution was indeed overrated by practitioners, in others CA proved to be useful models of important phenomena.