  Philosophers will recognize the theory as in some ways analogous to the theories of scientific development proposed by Thomas Kuhn (1962/1996) and others. Two important differences are worth mentioning, because they highlight what is distinctive about Piaget’s approach. First, although science develops organically, there is, for Kuhn, no one specific resource that applies across all fields. What explains the shift from one dominant paradigm to another in economics will typically not explain the shift from the Ptolemaic to the Copernican paradigm in astronomy. But Piaget held that what makes it possible for the child to advance in her understanding of space is in one sense the same thing as what facilitates the stage transitions in the child’s developing understanding of God or morality. Second, science depends on the contingent, uniquely fruitful innovations that overthrow older understandings and set the stage for new ones. But in children, Piaget’s developmental stages are posited as mandatory; we might say they are innately prescribed steps in normal development. The child’s forward motion is regularized as the world presents its predictable problems, and the new resources become available to solve them and advance the child’s understanding. The upshot is that although Piagetians produced probing and highly detailed studies of various domains of the child’s understanding, they shared the Empiricist preference for an across-the-board domain-general mechanism that could explain the developmental facts in every domain. Although there are interesting ideas inherent in the Piagetian paradigm about the innate endowment that makes adult cognition possible, it is not easy to place Piagetian Constructivism on the Nativist-Empiricist  spectrum.[18]