Why did Jane Jacobs oppose large-scale demolition and reconstruction in cities?

Jane Jacobs opposed large-scale demolition and reconstruction because she believed these modernist planning practices destroyed the complex social fabric of cities and imposed an "inhuman orderliness" on urban environments.1

In her influential work, The Death and Life of Great American Cities, Jacobs argued that the "rational model" of planning—often characterized by isolated officials directing wholesale clearance—failed to account for the human consequences of such decisions. Instead of viewing high population density as a problem to be solved through clearance, she championed it as a vital component of urban life.1

Jacobs advocated for the following principles as essential to healthy urban development:
* Diversity: She promoted a mix of population groups and land uses as a principal value, arguing that diversity contributes to sustainable growth.1
* Street Life: She believed that lively, active streets make cities attractive and functional.1
* Organic Growth: She favored the rehabilitation of existing buildings and adaptive reuse over the destruction of established neighborhoods.1

Ultimately, Jacobs argued that cities thrive on complexity and variety, whereas large-scale, undifferentiated projects lead to stagnation.1