Scale, causality, complexity and emergence: rethinking scale's ontological significance

Scale remains a pivotal yet highly contentious concept in geography. I survey the lively discussions engaged in recently by many critical/radical geographers regarding the theoretical status of scale. While these discussions have been intellectually fruitful, I argue that much more needs to be said. Drawing from complex systems theory, I argue that scale should be understood as an ontological category essential to understanding causality. Revalorising Aristotle's four categories of cause – formal, final, material and efficient – from two centuries of positivist thinking facilitates this endeavour. Research on the relationship between university-based poultry scientists and the poultry industry illustrates the explanatory potential of poly-scalar analysis.