John Rawls, a giant of modern political philosophy, has worked throughout his career to articulate the theoretical foundations of liberalism. Almost against his will, Rawls has suggested that those foundations are entangled with, and fortified by, religious faith.
Liberalism has always staked its claim to govern on its superior rationality. The modern liberal tradition, with its premise of the natural freedom and equality of all, arose in the 17th century partly in response to the turmoil of Europe's wars of religion. When John Locke set out in his first Letter concerning Toleration (1689) to demarcate the sphere of life that belonged to religion and the sphere that belonged to secular authorities, he relied on reason rather than religion to map the boundaries. In the 18th and 19th centuries, in the writings of Montesquieu, James Madison, John Stuart Mill, and others, liberalism forged an alliance with the commercial spirit, science, and democracy. These were the forces associated with progress, while religion was generally equated with reaction. In the 20th century, the liberal tradition faced the eruption of the forces of unreason in hideous secular forms--Nazism and communism--and defeated them. At the beginning of the 21st century, a threat to the liberal tradition has erupted again, this time drawing strength from religion.
Over the centuries, however, the liberal tradition has also drawn strength from religion. Locke viewed the law of reason--a moral law that he regarded as universal and objective--as an expression of God's eternal order. He also argued that religion, no less than reason, taught toleration. In the 19th century, Alexis de Tocqueville argued that liberal democracy in America depended on the vitality of the people's religious faith. Hegel sought to show that the liberal state is Christianity in secular and political form. Today, even as the United States wages a worldwide war against religiously inspired terrorism, religion remains a powerful force within America itself.
Yet at the heart of the liberal idea a question remains: Is it reasonable for a liberal to be religious? Can it be reasonable to claim to put freedom first while also binding oneself to a system of theological notions about where we come from, what we are, and how we ought to live? Such doubts have a distinguished pedigree in the liberal tradition, and they have impelled many contemporary liberals to regard religion with intense suspicion, if not outright hostility.
In the old quarrel between liberalism and religion, John Rawls, the preeminent academic moral philosopher of the last 50 years, has often seemed to encourage the view that while liberals must tolerate religious faith, it would be unreasonable for them to profess it. But with the publication at the end of his career of his Lectures on the History of Moral Philosophy (2000), Rawls's most searching examination of liberalism's foundations, he provides reasons to believe that far from being the antithesis of freedom, religious faith of a certain sort may be the basis of our respect for freedom, the very thing that renders our respect rational.
Rawls's Lectures is based on his notes for the class on moral philosophy he taught at Harvard University between 1962 and 1991. As in all his writings, he gives pride of place in these lectures to questions about moral reasoning. He is concerned above all with the logic of morality, its presuppositions, its principles, and the basic legal and political institutions that flow from it. Rawis finds inspiration chiefly in the daunting writings of the great 18th-century German philosopher Immanuel Kant. He does discuss other thinkers. David Hume, with whom he begins, raised the question that Kant attempted to resolve: How can there be universal moral standards untainted by our passions and interests? Part of Kant's answer is elaborated in the Critique of Pure Reason (1781): The very structure of reason, independent of our passions and interests, provides universal standards. …