LIBERALS are in the market for new ideas. For roughly 30 years, they ran the world. Starting in the early 1980s, free markets, globalisation and individual freedoms flourished. Liberalism—in this broad classical sense, rather than the narrow American left-of-centre one—saw off communism as well as social conservatism. Then, in the crash of 2008, it all fell apart.

As this week’s Books and Arts section explains, the financial crisis unleashed economic austerity and the rise of populism. Liberals, in charge of government and the banks, got the blame. They have been paralysed ever since.

One source of new ideas is debate. That is the aim of our Open Future project, marking The Economist’s 175th anniversary with essays, debates, reports, podcasts and films. Another source is the past. That is the job of our philosophy briefs, which start this week with John Stuart Mill (pictured). The ideas of old liberal thinkers still hold lessons.

Run of the Mill

What emerges? Liberalism is pragmatic. John Maynard Keynes, a lifelong champion of the liberal ethos, advocated government intervention during recessions to avoid the social ruin of economic collapse. The welfare state was not a socialist creation, as both right and left assume, but a liberal one—so that individuals are free to achieve their full potential.

Thanks to this pragmatism, liberalism is a broad church. John Rawls was a progressive American academic, his counterpart Robert Nozick a libertarian. Keynes believed in intervention; Friedrich Hayek and his fellow mid-20th-century Austrian, Joseph Schumpeter, insisted on the freest of free markets. (We urge readers who think our choice of dead white men too narrow to add their favourite liberal thinkers to our Literature of Liberalism—economist.com/liberalthinkers.)

And liberals think concentrations of power pose a threat. If anyone should have known that intellectual dominance would lead to disaster, as it did in 2008, liberals should have. Mill thought that no argument was ever settled definitively. Alexis de Tocqueville, the great chronicler of liberal America, cherished the diversity of local groups as a guard against state power. Yet the liberals in charge before the financial crisis were convinced that they had all the answers. In protecting what they had, they stopped thinking.

Were the great minds still humming today, three things would trouble them. The first is the steady erosion of truth by “fake news”, Twitter storms and viral postings. Liberalism thrives on conflict. But for argument to be constructive, it must be founded on good faith and reason. Today both sides talk past each other. The idea has become common, on both right and left, that when people put forward an argument you cannot separate what they say from who they are.

The second worry is the erosion of individual freedom. Mill popularised the term “the tyranny of the majority”. He supported democracy, including women’s suffrage, but warned how, as now in Turkey and the Philippines, it could turn into mob rule. Separately, Isaiah Berlin, an Oxford academic, would have seen that “no platforming” in order to protect minority groups comes at the cost of individual speech.

Last, the great thinkers would have lamented liberals’ faltering faith in progress. New technology and open markets were supposed to spread enlightenment and prosperity, but many people no longer expect to live better than their parents did. As democracies drift towards xenophobic nationalism, universal values are in retreat. And for the first time since the heyday of the Soviet Union, liberalism faces the challenge of a powerful alternative, in the form of Chinese state-capitalism.

Today’s liberals like to think that they are grappling with uniquely difficult issues. They should consider their forerunners. Mill and Tocqueville had to make sense of revolution and war. Keynes, Berlin, Karl Popper and the Austrians confronted the seductive evils of totalitarianism. Today’s challenges are real. But far from shrinking from the task, the liberal thinkers of yesteryear would have rolled up their sleeves and got down to making the world a better place.