Long ago, before Westerners associated "enlightenment" with meditation or yoga, there was the Enlightenment: the philosophical revolution of the 1600s and 1700s that made the modern West. Before the Enlightenment discovered natural rights, most people had no rights, speech was restricted, and few governments were accountable to their subjects. Enlightenment ideals are still common ideals: tolerance and equality, reason and science, an educated, engaged public. But today, we are witnessing the decoupling of Enlightenment principles from Enlightenment practices.

The Enlightenment was what historians call a "grand narrative." For full effect, say it with a smirk. How foolish those costumed dreamers were to believe in the advance of human knowledge, the dignity of all individuals, and the right to think, speak, and pray as we choose. How much cleverer we are, to not bother at all with such questions as we stroke our screens. As G.K. Chesterton said, "Everything matters—except everything."

The ideal of infinite progress is, ironically, an Enlightenment inheritance: Before the modern age, progress was in the hands of the Almighty, and moral authority rested with kings and churchmen. We might see this more clearly, if only we could settle on what the Enlightenment was. Everyone knows that it happened, but no one agrees on when, why, or where. The Enlightenment aspired to scientific reason, and the discovery of universal principles. But we, locavores in taste, are local in perspective too. Since 1989, and the demise of Marxism, one of the Enlightenment's grander narratives, historians have subdivided the Enlightenment like developers with condos. Now, we look back and see many Enlightenments. French dandies discourse wittily about Reason, and why it is reasonable to destroy the church. Red-faced Brits exchange their claret for coffee, and ponder the uses of Adam Smith's invisible hand. Practical Americans discover their natural rights in the wilderness. The Germans take off their clothes and commune with Nature. The Jews keep theirs on, and commune with the Germans. Everyone enlightens, but in their own way.

There is much to be said for this picture, give or take the naked Germans. The Enlightenment was a broad phenomenon—often, we use it as a synonym for "modern life"—but its outcomes depended on local variations. This is the relationship of climate and weather: the varieties of the latter confirm the stability of the former, but the relationship between the two is always unstable. Vincenzo Ferrone, the Italian author of the forthcoming Enlightenment: History of an Idea, calls the Enlightenment a "centaur": an impossible combination. It was a set of abstract philosophical ideals, but it was also a lived historical experience, full of ordinary disappointments and irregularities. We know what a centaur should look like, but we never see one in real life.

"Ah, but a man's reach should exceed his grasp," Browning wrote, "Or what's a heaven for?" The Enlightenment was the first modern "theory of everything." Out with empires, slaves, and priests; in with nations, free minds, and free publics. If the world could be known entirely, society could be reconstructed along improved lines.  That, at least, was the theory. In practice, some of the Enlightenment's local variations were terrifying, not least because the theorists of the Enlightenment thought they knew better than everyone else. The Enlightenment was made by intellectuals, and frequently for them, too. The modern intellectual prides himself on his selfless rectitude but, like the medieval churchman whose power he supplanted, he can spy a distant horizon because he looks down from a lofty height. Voltaire reviled the church, but thought religion was a good way to keep the plebs in line: better that the little folks clung to their religion than to their guns. Rousseau loathed authority, but he awarded his Enlightened state the dictator's privilege of "forcing people to be free."

"These days," Goethe said, "there remains no doubt that world history has from time to time to be rewritten." Historically, managerial elitism has been a reliable paver of the road to hell. Today, the technocrats chase a mirage of perfection, allegedly on our behalf. Lawrence Lessig tells us that we should abandon the eighteenth-century ideals of intellectual copyright, and the Constitution; perhaps Google can sponsor a Second Constitutional Convention? Cass Sunstein tells us that we cannot be trusted to make informed decisions, so the government must "nudge" us toward "healthy" choices. Why let us eat cake, when we can be forced to make free at the salad bar? These are odious ideas, the kind of suggestions that Rousseau might have made if he had worked in advertising. They reflect a widening distance between the governors and the governed, the tenured and the temporary, the rich and the poor.

The greatness of the Enlightenment lies less in its ideals, than in our efforts to realize them. The tragedy of the Enlightenment lies there too. History is made in the middle ground between theory and practice. But the middle ground, economic, social, and political, is a bad place to be in the modern West. The Enlightenment was never automatically democratic in the modern sense. The path from the Enlightenment ideal of Nature to the Enlightenment politics of natural rights often ran into the mud of the middle ground. Intellectually, the Enlightenment was always an elite business. And in business, ethics are always challenged by commercial realities.

Today, the ideals of scientific enquiry and free exchange survive, but at the expense of the Enlightenment inheritances that shaped the democratic nation state: civic tolerance, genuinely free speech, and an engaged, educated public. In the free market of American spirituality, "enlightenment" means the sweaty contortions of the yoga studio, where bodhi is only personal, never political. An educated middle class appears to be a luxury we can no longer afford. If nothing fails like success, then the Enlightenment is failing wonderfully.

"I must create a system, or be enslaved by another man's," said William Blake, full of Romantic doubts about Reason and a planned society. When the visionaries presume to plan on our behalf, we are no less obliged to refuse their presumption. Like Kant said, we are autonomous subjects, providing we try to act like it. If we outsource the intellectual labor of decision-making to the upper crust, or surrender to the bread and circuses of digital entertainment, we cannot complain about the results. Long ago, before the Enlightenment, people cowered before governments and speech laws. The Enlightenment offered an alternative, but it is one that must continually be affirmed: by public actions, by intellectual engagement, and by voting. We must make our own Enlightenment, or be chosen by someone else's.