In this paper we set out a theoretical account of how we suppose commonsense reasoning about motion may develop.~identify some of the most primitive building blocks necessary to the construction of a psycho-logic of motion. Our analysis shows how such primitive elements could combine together to provide schemes of motion, recognisable in psychological accounts of infancy, which themselves generate both prototypes of and rulesfor motion used in commonsense reasoning. The theory takes as fundamental the basic (essentially Kantian) categories of commonsense reasoning: action, object, space, cause, time and movement. J# also start with Piaget's intuition that action and movement areprimitive and fundamental to all development. A number of levels are suggested from the initial primitive schemes, emerging rules and prototypes, new prototypes from combinations, projection ofprototypes onto other objects and elaboration. Examples are given of prototypes which are the link between the deep seated ways of thinking and commonsense reasoning.