Toward a Multi-Scale Science of Cities: Flows, Networks, and Scaling Laws

We live in an age defined by cities. Although it is challenging to claim that the term “city” carries the same meaning it did thousands of years ago, many of the regularities observed in contemporary urban systems echo those found in ancient settlements. Urban scaling laws, power-law distributions of city size, and related fundamental principles governing urban organization repeatedly emerge across ancient contexts. These parallels are not coincidences; they point to enduring processes that shape how human societies organize themselves in space, processes that transcend time, geography, and culture.

Modern urban theory begins with the foundational idea that cities exist because people come together to interact. If interaction is the core of urban life, then understanding cities requires examining the networks, flows, and exchanges that allow people to communicate and collaborate. This insight runs like a thread through decades of urban thought. From Jane Jacobs’s The Death and Life of Great American Cities (1961) to Michael Batty’s The New Science of Cities (2013), scholars have emphasized a crucial conceptual shift: cities should not be viewed merely as physical spaces or static places but as products of interactional processes, where locations emerge from evolving networks of relationships that bind people together.

This project is rooted in these intellectual foundations, with a particular focus on urban scaling theory, which we view as a central pillar of urban science. Scaling laws are deeply intertwined with a wide spectrum of urban attributes and operational dynamics, offering conceptual and empirical insights relevant to both social concerns such as segregation and inequality and environmental goals including resource efficiency and emissions reduction. In this project, we adopt a network-based perspective on urbanism and employ a hybrid methodological framework that integrates mathematical modeling, agent-based simulation, and data-intensive empirical analysis. Our aim is to re-theorize and re-model the origins of urban scaling laws in a way that is both more comprehensive and more closely aligned with the complex realities of urban systems.

The significance of this project is twofold. First, it yields insights that can inform more equitable, resilient, and sustainable urban development. Second, it establishes a conceptual and methodological bridge between contemporary urban regularities and the deep urban past, offering a more complete understanding of how core mechanisms of urbanization evolve or persist across time. Ultimately, this project seeks to advance a unified and empirically grounded framework for understanding cities.

This project is undertaken within the Max Planck Postdoctoral Program framework (2025 cohort).