The issues regarding complex systems and the validation of their models has recently come on the fore; as Cellular Automata do belong to this category, they are directly involved in this revision. A major issue arising from the debate regards the procedure adopted to test models of these systems: application of a priori ipotheses to one case study. This kind of procedure is seen as unreliable, and as a generator of misleading models, whose predictions do not have solid foundations. Analyzing the problem in a general perspective, it (that is, the choice of the family of models to use) could be formulated as an inverse problem, based on an inductive method, which tries to formulate rules gaining information from data and doing the least number of a priori ipotheses.