But there is a deeper reason for its decline. At least in Western Europe and North America, most of us now tend to conceive of reason and religion as belonging to distinct and even incompatible domains. Modern believers, irrespective of confession, pattern themselves after the Protestant model: religion has withdrawn into a space of privacy and irrationality where its truth must be accepted not on the basis of philosophical argument but on faith alone. Atheists and theists, even if they disagree about everything else, agree that God and Reason belong in different houses; their quarrel is about the legitimacy of each domain and their possible relations, not the separation between them. In the concluding pages of his book, [Carlos] Fraenkel offers the exceedingly curious suggestion that modern theorists of liberalism such as John Rawls still cleave to the interpretative principle of philosophical religion: Rawls held that religious citizens should be permitted to participate in liberal deliberation, provided that they translate their claims into the neutral language of public reason. Here Fraenkel pushes too far, since the translation proviso is meant to expose a non-religious rationality behind religions rather than a common religious core.
This breakup of the old philosophical union between God and Reason is another name for the great disentanglement in the history of ideas that some theorists still call secularization. The breakup may strike us as irrevocable. But if Fraenkel is right, then the story of philosophical religion reveals a painful irony: the democratic sentiments that now inhibit us from distinguishing between non-philosophers and philosophers have also made it increasingly difficult for us to look past the literal contents of various religious traditions to a shared philosophical commitment within. Our own egalitarianism, in other words, is an obstruction to the kind of contextualist pluralism once upheld by the most subtle thinkers of the Abrahamic religions. The most zealous advocates for religion today are populists and literalists, and they have abandoned the principles of interpretation that made philosophical religion a possibility. Nathan’s is a lonely voice in the midst of war.