It’s not a surprising message from the renowned champion of the poor, and Pope Francis has had a great deal to say about urban development’s impact on human life. Speaking in New York in September, he declared that “God is living in our cities,” and celebrated urban diversity while condemning “the roar of traffic” and smog.

In “Praise Be,” an encyclical released in May that was focused on the environment, Francis also examined “current models of development” that he said included the “disproportionate and unruly” growth of many cities. Those cities are threatened by “toxic emissions . . . urban chaos, poor transportation, and visual pollution and noise.”

He also said that many cities are “huge, inefficient structures . . . congested, chaotic, and lacking in sufficient green space. We were not meant to be inundated by cement, asphalt, glass and metal, and deprived of physical contact with nature.” The most beautiful parts of cities, he contended, are often “closed to outsiders in order to ensure an artificial tranquility.”

It’s a ripe time for the Holy Father to take a stand on cities. More than half of the world’s population is now urban, and the United Nations says that will reach two-thirds by 2050. Urban planning is frequently contentious, whether in Cape Town or Portland, as New Urbanism’s support for walkable, ‘green’ development pushes back against the growth of overpasses and high-rises.

That tension in urban planning may be best embodied by two famed rivals—Robert Moses and Jane Jacobs. For much of the 1930s through 1960s, Moses wielded huge influence in planning New York City by pushing for big projects like bridges, parks, and public housing. Jacobs became a vocal critic of Moses in the 1950s, championing neighborhoods instead of megaprojects. Their opposition has been increasingly mythologized, with an opera on the way to accompany recent comic books and endless think pieces.

So, the inevitable question: Does the Pope side with Jacobs, or (no pun intended) Moses?

It may seem like a gimme. Moses famously flexed his power on behalf of the cars that the Pope seems to scorn. Moses also had no problem bulldozing entire (largely poor) neighborhoods as head of New York’s Committee on Slum Clearance. His reputation has become that of an uncaring authoritarian, while Jacobs is seen as a champion of the little guy. At least by sentiment, it would seem Pope Francis would side with Jacobs.

But a deeper dive makes the question more complicated. Moses pushed hard for the green space the Pope feels is so vital by creating major public parks as well as 658 playgrounds in New York. While high-rise public housing is now widely seen as a broken model, Moses built more than 150,000 housing units that, at least in a basic material sense, improved living standards for the poor—an accomplishment that recent New York leaders must look on with envy. And though the highways Moses loved have been condemned as short-sighted alternatives to public transit, their like would be welcome aids to much of the developing world’s mounting gridlock.

Jacobs’ legacy is perhaps even more counterintuitive. Her advocacy of cities made up of ‘little villages’ has, indirectly, helped turn places like Brooklyn and her own beloved Greenwich Village into exactly the sort of gentrified enclaves that the Pope rails against in “Praise Be.” As the Guardian once put it, many of the very neighborhoods Jacobs helped save have become “malls for tourists that are just as soulless as the cultural centres and high rises she abhorred.”

All of which may only show that, where cities are concerned, we’re still figuring out how to solve the very complex problems of housing, transportation, and services. Even the Pope can’t untangle the contradictions along the way—he preaches against smog, but gets around in a car.

Albeit, famously, a very small one.

For more about Pope Francis, watch this Fortune video: