Do you believe in evolution? I do. But when I say "I believe in evolution," I mean something rather different than when I say “I believe in liberal democracy.” Evolutionary theory is a science. Liberal democracy is a political philosophy that most of us think has little to do with science.

That science and politics are nonoverlapping magisteria (vide Stephen Jay Gould’s model separating science and religion) was long my position until I read Timothy Ferris’s new book The Science of Liberty (HarperCollins, 2010). Ferris, the best-selling author of such science classics as Coming of Age in the Milky Way and The Whole Shebang, has bravely ventured across the magisterial divide to argue that the scientific values of reason, empiricism and antiauthoritarianism are not the product of liberal democracy but the producers of it.

Democratic elections are scientific experiments: every couple of years you carefully alter the variables with an election and observe the results. If you want different results, change the variables. “The founders often spoke of the new nation as an ‘experiment,’” Ferris writes. “Procedurally, it involved deliberations about how to facilitate both liberty and order, matters about which the individual states experimented considerably during the eleven years between the Declaration of Independence and the Constitution.” As ­Thomas Jefferson wrote in 1804: “No experiment can be more interesting than that we are now trying, and which we trust will end in establishing the fact, that man may be governed by reason and truth.”

Many of the founding fathers were scientists who deliberately adapted the method of data gathering, hypothesis testing and theory formation to their nation building. Their understanding of the provisional nature of experimental findings led them naturally to form a social system wherein doubt and disputation were the centerpieces of a functional polity. “The new government, like a scientific laboratory, was designed to accommodate an ongoing series of experiments, extending indefinitely into the future,” Ferris explains. “Nobody could anticipate what the results might be, so the government was structured, not to guide society toward a specified goal, but to sustain the experimental process itself.”

For example, the political belief of John Locke that people should be treated equally under the law—which factored heavily in the construction of the U.S. Constitution—was an untested theory in the 17th century. In fact, Ferris told me in an interview, “few thinkers prior to the advent of the American liberal-democratic experiment thought democracy could work in any but the most limited forms” and that most political theorists believed that “the common people are too stupid and ignorant to be trusted electing their leaders.” And yet, Ferris continued, “liberal democracy did succeed and is today the stated preference of the majority of the world’s peoples, including both those who live in democratic nations and those who don’t.” What would constitute a failed experiment in the political laboratory? "If it ceased to exist in the nation under examination and was replaced by something else. Such was widely predicted to be the fate of the liberal democracies, but the verdict of experiment was otherwise: liberal democracy turned out to be the most stable and long-lasting form of government ever instituted."

But, I protest, aren’t all political claims types of beliefs? No, Ferris responded: “Liberalism and science are methods, not ideologies. Both incorporate feedback loops through which actions (e.g., laws) can be evaluated to see whether they continue to meet with general approval. Neither science nor liberalism makes any doctrinaire claims beyond the efficacy of its respective methods—that is, that science obtains knowledge and that liberalism produces social orders generally acceptable to free peoples.”

The myth of the scientific method as a series of neat and tidy steps from hypothesis and prediction to experiment and conclusion is busted once you go into a lab and observe the more haphazard and messy realities of how researchers feel their way toward discovery. So it is with liberal democracies, which almost never work out as planned but somehow progress ever closer to finding the right balance between individual liberty and social order. The constitutions of nations are grounded in the constitution of humanity, which science is best equipped to understand.