planning theories, epistemology, 21st century, climate change, mitigation strategies, decision-making


Planning is an iridescent term. A glance at the literature shows how diverse the term planning can be understood, for example as state action, as spatial distribution of different zones or infrastructures, as governance arrangements of different actors, or as civil society engagement for the common good, and many more. Planning practice is defined accordingly in abstract terms in the literature: Planning as "linkage between knowledge and organised action" (Friedmann and Hudson, 1974, p. 2), i.e. connecting knowledge and action, or as an attempt to control the future ("planning as future control", Wildavsky, 2018, p. 128) or "planning activity as practice of knowing" (Davoudi, 2015, p. 317). Gunder (2010, p. 299) described planning as the ideology of how we define and use space, whereas Brooks (2019, p. 9) understands planning as the process by which we try to shape the future. These and other definitions do have in common a strong orientation towards the future (i.e. it is not just a description of the present), which is accompanied by a direct normative orientation towards action. As Alexander (2016, p. 92) already noted, the problem with all these definitions is not that they are not true, but rather that they are too abstract for a definition. These definitions are hardly sufficient in narrowing down what is (and especially what is not) meant by the term spatial planning. It is undisputed that the future orientation of spatial planning undermines a concrete analytical understanding, "the object of planning, future action, routinely involves the unique and novel" (Forester, 1982, p. 3). Nevertheless, or perhaps rather because of this, it is essential to explain the underlying understanding of planning.


However, our respective understandings of planning are dependent on our theoretical perspectives, shaping our reality(ies) and perceptions, determining our problems and solutions, and how society deals with it. In this process, theories serve as lenses, as glasses through which we grasp the world out there, make it tangible and discussable, cast it into constructs of realities and define all our assumptions. One of the profound experiences in dealing with planning theories has been the realisation that these theoretical lenses can be changed, so that at one time spatial distribution issues are in the

foreground, at another time the actors behind them and their possibilities for action. What changes by switching the perspective is all-encompassing: the problem definition, the approach to the solution, the methods and forms of knowledge selected, the possible aims to be achieved, and not least the fundamental understanding of what we call spatial planning. It is therefore all the more astonishing that in many discussions and publications it is precisely the study of planning theories that is degraded as being of little benefit to practice (Alexander, 2016, p. 95).

With this article, we engage to contribute to a re-organisation of knowledge for planning in the 21st century. Numerous challenges, be it the impacts of climate change and adaptation and mitigation strategies, or societal polarisation and the question of appropriate decision-making, require an accessible planning knowledge to be combined in interdisciplinary contexts as well as transdisciplinary research questions with society. Therefore, we urgently need to restructure our planning knowledge for a fundamental integration of spatial and planning perspectives on these challenges, but also its paradigmatic limitations and blind spots. First, we introduce a novel systematisation of planning knowledge according to the specificity of future orientation in planning knowledge (section 2). In the following we investigate a systematisation of multiple levels of planning theories according to their action orientation (section 3). In section 4 we present the entire Topologie of Planning Theories based on the relation of different planning theories towards each other in the knowledge field with different ontological and epistemological orientations. In concluding remarks we reflect upon this systematisation and explain the benefit from this re-organisation of planning knowledge.