The ontological problem is "what exists?" The answer regarding the part of consciousness which is related to left hemisphere is that only individual discrete objects exist; objects are regarded one at a time. The answer regarding the part of consciousness which is related to right hemisphere is only comprehensive entities exist; each…

Discussed is the research method of "didactic engineering" and the potential theoretical problems of putting research findings into practical use as teaching methods in mathematics classrooms. Cited is the possible incompatibility between the theoretical principles of experimental methods and teachers' conceptions. (MDH)

Reports a study designed to identify 9 and 11 year olds' ways of drawing nets of solids and to provide opportunities for them to reflect on their models in whole class discussions. Results indicated that children's views of solids' nets progressed from more global and holistic to more quantitative and analytic. (MDH)

Begins with the assumption that by practicing something one often learns something else. A discussion is presented on the historical and social development of knowledge, the cognitive development of students, the role of teachers, and the meaning of learning situations. (PK)