John Rawls saw a “plurality of reasonable but incompatible comprehensive doctrines” as a “fact” about the world, or at least about the modern world. He explained: “a reasonable doctrine is an exercise of theoretical reason: it covers the major religious, philosophical, and moral aspects of human life in a more or less consistent and coherent manner. It organizes and characterizes recognized values to that they are compatible with each other and express an intelligible view of the world” (Political Liberalism, New York: Columbia University Press, 1993, pp. xvii, 59).

Since my first book, I have been criticizing this assumption that the world is divided into separate, internally coherent worldviews. It’s certainly not Rawls’ assumption alone. I would define “modernism” as the premise that there is a plurality of incompatible comprehensive views. And I would assert that modernism is a mistake, driven by certain confusing metaphors: culture as a perspective, culture as a structure built on a foundation, culture as a table of values. I’d prefer a metaphor of overlapping horizons or a model of cultures as interconnected networks of ideas.

If anyone holds a “comprehensive doctrine” that is incompatible with other views, it would be a religious authority in one of the Abrahamic faiths. For instance, in 2011, during the turmoil of the Egyptian revolution, the most senior cleric who had been appointed under the old regime of Hosni Mubarak, the Grand Mufti of al-Azhar University, gave a sermon against political “extremists”:

They preferred to learn in their own beds at home from The Book with neither a methodology nor a master, so they stopped at the outer shell of Islam without realizing its goals and meanings. They stopped at the surface and they failed to realize the truth behind matters and the truth behind rules. They stopped at the partial and failed to see the whole. They favored the specific over the general. They favored their own interest over the interest of the ummah [nation or community].

Here a theologian and jurist asserts that his religion is fully coherent and centralized. This cleric, Ali Gomaa, goes on to address particular issues; for example, he opposes destroying the idols of other faiths, which he calls  an act of extremism. He argues that to make such judgments correctly, one must apprehend the core of the true faith—or else follow a master who possesses such knowledge.

This is a familiar rhetorical move within any faith tradition. For an outsider, it may seem obvious that the faith is a “comprehensive doctrine,” uniting all believers into the same structure of reasoning. But a learned member of the faith always knows that almost every element of it is contested within the tradition. Certainly, Gomaa would be aware that the Islamic Brotherhood and Salafi sheiks were preaching different messages in Egypt at the same time.

Gomaa did not actually specify how the core truths of Islam led to his particular judgments. He wanted his listeners to picture a chain of reasoning that flowed from the core of the faith to the particular cases, but he did not spell it out. That is because his purpose was to assert authority, not to offer reasons. One can offer reasons within a faith tradition, but that will be a matter of picking a path through a complex web. And many of the nodes and connections in that web will be shared with other faiths, so much so that the borders between faith traditions are often blurred.

The problem for liberalism is not that citizens hold strong and controversial metaphysical commitments. Citizens in a liberal regime may believe that Jesus is their personal savior or that science delivers the only valid truths. The problem is a moral network that is overly dependent on a few central ideas. And that is not intrinsic to a religion. To put it a different way: It is not a fact that the world is divided into comprehensive and incompatible doctrines. It is a choice to view it that way.