Beyond Turing Equivalence

What is the relation between intelligence and computation? Although the difficulty of defining "intelligence " is widely recognized, many are unaware that it is hard to give a satisfactory definition of "computational " if computation is supposed to provide a non-circular explanation for intelligent abilities. The only well-defined notion of "computation " is what can be generated by a Turing machine or a formally equivalent mechanism. This is not adequate for the key role in explaining the nature of mental processes, because it is too general, as many computations involve nothing mental, nor even processes: they are simply abstract structures. We need to combine the notion of "computation " with that of "machine". This may still be too restrictive, if some non-computational mechanisms prove to be useful for intelligence. We need a theory-based taxonomy of architectures and mechanisms and corresponding process types. Computational machines my turn out to be a sub-class of the machines available for implementing intelligent agents. The more general analysis starts with the notion of a system with independently variable, causally interacting sub-states that have different causal roles, including both "belief-like " and "desire-like " sub-states, and many others. There are many significantly different suc