There are at least two definitions of “urbanism” that are opposites of each other. The first one claims that urbanism is a standalone discipline that studies cities with its own theoretical and methodological frameworks. The second one understands urbanism as a topic that can be explained by different theories with various methods; as a topic, urbanism is essentially an umbrella term for everything cities entail.
I support the second definition, because the urban environment is a collective construct of social, political, economic, engineering, ecological, and cultural dynamics. Each of these aspects can be approached and understood via its respective disciplines. I avoid the first definition of “urbanism” as a discipline, because it is difficult for me to imagine studying cities via only one way.
Sometimes, when urbanism functions as a discipline of its own, it applies the theories and methods of architecture directly to issues of larger scales. “The city is a big house” and “My building is a city” are typical mantras of this school. For me, these statements are problematic, because the scalar difference between buildings and cities brings about complex changes in many other dimensions. If a 100 square-feet room makes one person feel cozy because the architect made specific choices of proportion and materiality, she cannot deduce that a similarly designed 10,000 square-feet plaza can make 100 people feel the same kind of intimacy. This is because the quality of a public plaza depends not only on its architectural quality; its meaning also results from the economic, political, and social functions of the urban system. Because it takes different kinds of organizational resources to make cities than to construct buildings, larger territories (such as neighborhoods and towns) are qualitatively different from smaller ones (such as a room or a shed). The difference is not only in size, but also in the financing, planning, and governance of complex physical and social environments. Therefore, it is insufficient to study architecture and cities with the same logic, and I will not assume that the relationship between these two realms is linear.