We argue that creative ideas are potentially valuable improbable constructions. We arrive at this formulation of creativity after considering several problems that arise for the theories that suggest that creativity is novelty, originality, or usefulness. Our theory avoids these problems. But since we also derive our theory of creativity from the scientific commitments of a more general theory of cognitive development, a theory called rational constructivism, our theory is unique insofar as it explains creativity in both adults and children through (...) reference to a set of computational mechanisms that have been posited on the basis of independently plausible experimental research. (shrink)