ABSTRACT
This chapter presents the implications of Jean Piaget's genetic epistemology for the relationship between knowledge and action. This laid the foundation of our belief that social science and planning cannot be completely objective and value-free and that a theory of design and a theory of planning are both extremely important. Several reasons justify an interest in Jean Piaget's epistemological ideas. The nature of epistemology is defined as follows: epistemology is the study of the constitution of valid knowledge. A theory of planning would be a reflexion on the practice of planning. It would therefore be an epistemology of planning which would attempt to explain the manner in which planning is practiced, how 'problems' and institutions appear. A proper balance between the development and teaching of planning theory and design theory is necessary for the progress of urban planning.
