 Finally, another kind of formal model for a different kind of unity straddles the boundary between formal epistemology and ontology: computational models of emergence or complexity. They are based on simulations of chaotic dynamical processes such as cellular automata (Wolfram 1984; Wolfram 2002). Their supposed superiority to combinatorial models based on aggregative functions of parts of wholes does not lack defenders (Crutchfield 1994; Crutchfield and Hanson 1997; Humphreys 2004, 2007 and 2008; Humphreys and Huneman 2008; Huneman 2008a and b and 2010).