ABSTRACT
People known for a long time that at every level of knowledge, from infancy to scientific thinking, physical experience cannot be interpreted, or even read off, without an assimilating framework that is logic-mathematical. These amounts to saying that empirical abstraction and reflecting abstraction always go together. Since all empirical abstraction requires an assimilating framework, reflecting abstraction must be present at every stage of development, not just Level IB or later. But many problems arise when people try to detail these relations, especially at the elementary stages. This chapter addresses the questions in the context of a problem that requires physical reasoning with particularly constraining data. In these elementary stages it includes: stage I; stage II and stage III. Stage II extends from age 7 to age 10, is marked by two advances whose interrelations need to discover. The subject keeps track of the degree of error and uses this information to improve his performance on subsequent trials.
