Within the domain of planning, whether concerned with different subject areas or different geographical levels, ‘knowledge’ and ‘action’ rest on a dialectical interaction. Thus any attempt at investigating ‘planning theory’ must not only be based on the search for the role of ‘planning action’ against ‘knowledge’, but should also answer the questions concerning the foundations of theories, approaches, actions and activities of planning.
In this paper an attempt has been made to study the specifications and the current classifications of planning theories in order to be able to propose an all-embracing classification of planning theories and their corresponding approaches.
A proposed three-tiered classification starts with, first, the orthodox theories and approaches which have been accepted as a norm and as a framework for planning action in different societies. The second involves radical theories, and the third concerns notions, conceptions and ideas put forward in planning since the early 1990’s, such as post-positivism, post-modernism, neo-pragmatism and environmental planning.
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