Theoretical approaches to urban environmental planning

This thesis documents and examines seven histories of environmental and planning thought over the last century, drawing on Yiftachel's (1989) classification of planning theories. It provides evidence that environmental and planning theory over time is moving: away from the understanding of nature as an object; away from the notion of a unitary public interest in planning theory; toward an increasing recognition of uncertainty in environmental decisionmaking; away from instrumental rationality in planning decisionmaking; away from hard determinism in urban design and planning control theory; away from direct pollution controls in environmental policy theory.-- This thesis argues that these changes can be understood in the context of broader philosophical shifts around the issues of being, knowing and acting, involving a reevaluation of the relationships between: subject and object; value and fact; cause and effect.-- It suggests that the changes indicate a shift away from philosophical rationalism in policy theory over time. The thesis concludes that neither the extremes of rationalism or relativism provide a sound theoretical foundation for environmental planning. It suggests that future theoretical development is likely to come from the interaction of theoretical approaches influenced by non-Western cultures, and innovations produced by local cultures adapting existing theories to meet their specific needs.