ABSTRACT
It would be natural at this point to suggest new axiom-systems to serve as skeletons for further theories of the kind presented in Chapters 6–10. Such theories might bear on additional length abilities possesed by children, should it be the case that Grize’s axiomatization does not permit derivation of every principle children comprehend. In addition, the present data suggest that an entirely different set of axioms will be required to explain class-inclusion abilities. Other logical realms, e.g., the properties of subregions of a plane, also seem amenable to the present approach.
