The founders of cognitive science found it useful to remind everybody that no benevolent deity has issued psychologists an insurance against complexity. They implied that if the mind is complex, then we should expect theories of mind to reflect that complexity. H. A. Simon and A. Newell wrote that their “… theory posits internal mechanisms of great extent and complexity.… That is all there is to it.” The three micro-theories of creativity, adaptation and conversion proposed in this book conform to this expectation. In each case, the behavioral phenomenon that the theory was designed to explain can be described in one or two paragraphs, but its explanation requires a chapter-length exposition. If the ultimate theory of cognition is a conjunction of many such micro-theories, then that theory is complex indeed.

But the founders might have taken their realism a shade too naively. Scientific theories are human constructions and they are shaped as much by our ambitions, desires and needs as by the reality they explain. Scientists strive for concise principles because they cannot think effectively with complex ones, due to the very limits on cognitive processing that the founders themselves did so much to reveal.