I received a lot of praise for my column on how both sides of the gay marriage debate exhibit bigotry. But the column also inspired a lot of fury. Critics wrote me personally and took to Twitter to denounce me for describing some supporters of gay marriage as illiberal — and for standing up for the rights of those who oppose equal rights for homosexuals. Over and over I was asked: Isn't this like defending neo-Nazis or a lynch mob while criticizing the intolerance of those they seek to oppress? And all in the name of liberalism? It's outrageous. And offensive. And confused.

I'll admit it: Put like this, it does sound confusing.

But the confusion isn't in my mind — or in the mind of my critics. It's a result of the fact that we're talking about two different senses of "liberalism."

For many advocates of gay marriage, liberalism is a holistic, comprehensive ideology with its own distinctive vision of the human good. This vision advocates the autonomy of individuals from received traditions and their liberation from constraints both external (political, social, cultural, religious) and internal (psychological), which it invariably treats as forms of oppression. Liberalism in this sense denies that sexuality should be subject to moral judgment or evaluation of any kind, beyond the consent of the parties involved in the sexual act. As long as consent has been given, anything goes.

In addition to holding out this ideal of individual autonomy, comprehensive liberalism demands that each individual's choice of how to live be recognized and positively affirmed by everyone else, no matter what it involves (as long as it doesn't infringe on anyone else's equally free lifestyle choice). Comprehensive liberals also tend to treat the refusal to grant this recognition and affirmation as an act of illiberalism that ought not be tolerated. Many go so far as to think that liberal governments should force the recalcitrant to comply with the liberal ideal, at least in any area of life that can plausibly be described as public.

Liberalism in this sense is a zero-sum game, since its advance through public life often requires the equal and opposite retreat of non-liberal visions of the good. During the past several decades, we've seen it wash in waves over American society, culture, and politics, first with race, then with gender, then with disability, and now with gay marriage. The fight for transgender rights, recognition, and affirmation will almost certainly be next.

My own understanding of liberalism — which supports gay marriage while also tolerating religious traditionalists who reject it — grows out of a very different intellectual tradition. It derives, at its deepest level, from the classical virtue of liberality, which meant generosity and openness. This notion of liberalism underlies the idea of the "liberal arts" as a curriculum that at its best instills a sense of humility by opening a student to the full range of human experience, thinking, and feeling. It assumes that differences in life experience, psychological makeup, social class, intelligence, the capacity for introspection, and temperament will tend to produce a "natural" condition of pluralism in human social life.

Responding to this pluralistic reality — and reacting most proximately to the violence and war it produced in the theologically divided societies of 16th- and 17th-century Europe — the greatest early modern liberals (John Locke, Montesquieu, Adam Smith, David Hume, James Madison, Thomas Jefferson) devised a form of politics that could enable a society comprising individuals deeply divided about the good to live together in relative peace and freedom despite their differences.

The U.S. Constitution was the first and is still one of the greatest practical achievements of pluralistic liberalism, establishing a series of minimal rules to enable numerous clashing factions divided by a range of interests and ideals to govern themselves freely and fairly. The Constitution itself takes no position on the highest human good; on how to pursue happiness or what it consists of; or on whether there's a God and what he might want from us. Yes, it presupposes that individuals have rights, and (read in light of the Declaration of Independence) that those rights derive from a deistic "nature and nature's God." But that nominal metaphysical presupposition is the only one present in the document.

The agnosticism was intentional. Complete metaphysical neutrality might be impossible, but minimalism is both possible and desirable, since it opens up space for toleration of social, cultural, and religious diversity.

Toleration is the premier virtue of pluralistic liberalism — and a modern analogue to ancient liberality. Unlike comprehensive liberalism's zero-sum demand for recognition and affirmation, toleration upholds the ideal of "live and let live," allowing (within certain broad limits) diverse, clashing, morally conflicting ways of life to thrive, provided that they tolerate other ways of life to do the same.

When one way of life judges another harshly — think of religious traditionalists rejecting the legitimacy of gay marriage, for example, or gay marriage advocates attacking the homophobia of the Catholic Church — this can be difficult. But it remains essential to the functioning of liberal society and government. The hostile groups need not love or even respect one another's vision of the good. They need only agree to disagree in relative civility and peace.

Pluralistic liberalism was first proposed in early modern Europe and put into practice in the late 18th-century United States. It was theoretically bolstered by such 20th-century pluralists as Michael Oakeshott, Isaiah Berlin, Daniel Bell, and (in some of his late work) John Rawls. But its greatest modern-day exemplar may well have been Nelson Mandela.

Mandela risked his life and languished in prison for years in the name of a comprehensive ideal that was radically incompatible with apartheid. His steadfast, gutsy opposition to it made him a great moral hero. But it was his wise and courageous leadership after he became the first black elected president of South Africa that made him a great statesman.

Many people inside and outside the troubled nation expected a bloodbath once white minority rule came to an end. But Mandela’s moderation and restraint — above all in his emphasis on national reconciliation — kept South Africa from the brink and laid the essential groundwork for the construction of a diverse, multicultural democracy.

Yes, Mandela's vision of the good won the kind of total victory gay marriage advocates in America seek today, but it was the spirit of pluralistic liberalism that consolidated the new order in South Africa. Where justice seemed to demand harsh penalties for former leaders and collaborators, as well as fewer amnesties for horrific crimes committed against black South Africans, Mandela understood that the nation’s well-being depended on its citizens learning to live together in mutual toleration of their deep, painful differences. It was an extraordinary act of magnanimity that Americans on the winning side of the battle surrounding gay marriage ought to take to heart.

America’s cultural clashes are relatively minor compared to the national fissure South Africans confronted two decades ago. But that doesn’t mean we don’t have something important to learn from Mandela’s example of pluralistic liberalism in action.