I get this all the time: "Oh Deirdre, you're such a conservative." My friends seem to think politics operates exclusively on a left-right spectrum. They therefore suspect me and other self-described "libertarians" of being sneaky versions of Ronald Reagan and Margaret Thatcher.

In truth, libertarians sit nowhere on the left-right map, which merely captures a dispute about how to use the government's monopoly of violence. The right wants to use violence to support 800 U.S. bases abroad. The left wants to use it to boss poor people around. Libertarians want neither.

What is the difference between libertarians and conservatives? It is our unique belief in liberty and its spontaneous ordering, in the way that language or art or science is ordered. We see a world ordered by people having a go within a loose framework of honest rewards. Conservatives (and socialists and most people in the middle) believe in top-down order, as in a loving or authoritarian household.

You book-reading types know that I'm getting "spontaneous order" from Friedrich Hayek and borrowing my title here from his essay "Why I Am Not a Conservative," reprinted at the end of The Constitution of Liberty (1960). Hayek argues that both conservatives and socialists believe, along with most lawyers and soldiers and bureaucrats, that "order [is] the result of the continuous attention of authority." The extravagant modern growth of law as legislation embodies such a belief, to be contrasted with the older tradition of law as the discovered customs of our community. Problem? Make a law, and then go on holiday.

All points on the conventional spectrum, Hayek continued, "lack the faith in the spontaneous forces of adjustment." That's why they think they need to extend the government's monopoly of violence: to compel the barbarians and blockheads to get organized. "The [real] liberal," by contrast, "accept[s] changes without apprehension, even though he does not know how the necessary adaptations will be brought about."

No one in 1970 anticipated the internet. No one in 1900 anticipated that autos could safely whiz past each other on two-lane roads at a combined speed of 120 miles per hour. Almost no one in 1800 anticipated that liberalism was about to produce a 3,000 percent enrichment of the West. And almost no one in 1700 anticipated liberalism.

The conservative admires evolution up to a couple of decades before the present, but unlike libertarians he is fearful and angry about any recent or, God help us, future evolution. Adoption of children by gay couples, say. A social democrat, on the other hand, does not admire many of the evolutions up to the present, and unlike libertarians she is quite sure she can lay down a better future by compelling you to give up your stuff and your liberty—for your own welfare, of course. Industrial policy, say.

The true liberal, by contrast, admires some old evolutions—English common law, for instance, though not its enslaving doctrine of femme couverte—and looks with a cheery confidence to a future of unforced evolution from below, not statism from above.

The evolutions of the past two centuries have been splendid for poor people, raising real incomes by a factor of 30. What Adam Smith called in 1776 "the liberal plan of [social] equality, [economic] liberty, and [legal] justice" inspired ordinary people to have a go. Contrary to the beliefs of our conservative or socialist friends, the government was mainly, in the story of liberty and its material fruits, an obstacle: enforcing slavery and Jim Crow, imposing regulation and planning, marshalling armies to clash by night.

Nice consequences aside, liberalism is an ethical conviction. A liberal believes that as much as possible, no one should push others around, standing over them with a gun or a fist to force them to do his will. The liberal abhors hierarchy of men over women, masters over slaves, politicians over citizens. The liberal philosopher David Schmidtz argues that above all, each person should have the right to say no. "I would prefer not to," said Bartleby the scrivener in Melville's tale in 1853. As a free man, he could say that, whether or not it was good for him. He was an adult, and as an adult he was owed respect for his preferences—if not a paying job.

Notice that I have been slipping in the word liberal to describe what we believe. I want to take back the older l word and quietly retire the harsh history of libertarian. Plain liberalism is the great movement since the 18th century that has freed us to prosper in body and spirit. It was distorted into slow socialism by the New Liberals in the U.K. and the Progressives in the U.S., and into fast socialism, nationalism, and national socialism eastward.

Liberalism promises a "negative liberty" to be left alone—not a so-called "positive liberty" to be benefitted by a tax or protection extracted by governmental violence from other people. It is ethical, and in the modern world of toppled hierarchies it is viewed as quite ordinary good behavior. Tom Palmer of the Atlas Network has it right: "Chances are almost 100 percent that you act like a libertarian.…You don't hit other people when their behavior displeases you. You don't take their stuff.…Congratulations. You've internalized the basic principles of libertarianism," a.k.a. liberalism.

To understand what libertarians believe, we must consult two alternative formulations of the Golden Rule. The late first-century BCE Jewish sage Hillel of Babylon put it negatively: "Do not do unto others what you would not want done unto yourself." It's masculine, guy-liberalism, a gospel of justice, roughly equivalent to the non-aggression axiom as articulated by liberals from the Cato Institute's David Boaz to the Mises Institute's Walter Block.

But the early first-century C.E. Jewish sage Jesus of Nazareth put it positively: "Do unto others as you would have them do unto you." It's gal-liberalism, a gospel of love, placing on us an ethical responsibility to do more than pass by on the other side. We are enjoined to be good Samaritans—to be nice.

The world needs both. Each corrects the excesses of the other. The latter tempers an inhumane selfishness. The former reins in a busybody. (What we do not need is the new GOP's version: "Do unto others before they do unto you.")

In a word, be a liberal.