ONE of the anxieties haunting the 21st century is a fear that technological change will soon make many human lives seem essentially superfluous.

It’s a fear as old as the Luddites, but the promise of computing, robotics and biotechnology has given it new life. It suddenly seems plausible that a rich, technologically proficient society will no longer offer meaningful occupation to many people of ordinary talents, even as it offers ever-greater wealth, ever-widening powers and, perhaps, ever-longer life to the elite.

That anxiety dominates the most provocative conversation you can eavesdrop on this week, between the Nobel laureate Daniel Kahneman and the Israeli historian Yuval Noah Harari on the website Edge.org.

Harari, the author of a recent history of the human species, “Sapiens,” argues that our own era’s breakthroughs will create new classes and class struggles, just as the Industrial Revolution did.

Soon, if not tomorrow, the rich may be able to re-engineer bodies and minds, making human equality seem like a quaint conceit. Meanwhile, the masses will lose their jobs to machines and find themselves choosing between bread and circuses (or drugs and video games) and the pull of revolutionary violence . with the Islamic State’s appeal to bored youths possibly a foretaste of the future.

Harari’s scenario, as he concedes, is only a projection, and one may doubt that technology can go as far as he imagines. But some of the dislocations he envisions are already here: Work is disappearing for the erstwhile working class, the rich are increasingly self-segregating and marrying among themselves, and virtual realities are replacing older forms of intimacy.

What I find most provoking, though, is Harari’s insistence that in dealing with these problems, “nothing that exists at present offers a solution,” and “old answers” are as “irrelevant” now as they were (allegedly) during the Industrial Revolution.

He means this as a critique of religious revivalists in particular: Not only the Islamic State’s seventh-century longings, but any movement that seeks answers to new challenges “in the Quran, in the Bible.” Such seeking, he argues, led to dead ends in the 19th century, when religious irruptions from the Middle East to China failed to “solve the problems of industrialization.” It was only when people “came up with new ideas, not from the Shariah, and not from the Bible, and not from some vision,” but from studying science and technology, that answers to the industrial age’s dislocations emerged.

This argument deserves highlighting because I think many smart people believe it. And if we’re going to confront even modest versions of the problems Harari sees looming, we need to recognize what his argument gets wrong.

New ideas, rooted in scientific understanding, did help bring societies through the turbulence of industrialization. But the reformers who made the biggest differences . the ones who worked in the slums and with the displaced, attacked cruelties and pushed for social reforms, rebuilt community after it melted into air . often blended innovations with very old moral and religious commitments.

When technological progress helped entrench slavery, the religious radicalism of abolitionists helped destroy it. When industrial development rent the fabric of everyday life, religious awakenings helped reknit it. When history’s arc bent toward eugenics, religious humanists helped keep the idea of equality alive.

Over all, we overestimate how pious the West of 1750 or 1800 was . and we underestimate how much the more egalitarian West of 1950 was shaped by religious mobilization and revival.

Nor is this just a Western phenomenon. As the developing world has converged in prosperity with Europe and America, old religious ideas that have been given new life . Christianity in China, Hinduism in India, Pentecostalism in Latin America and Africa . are playing as important a social role as any secular or scientific perspective. (In the Middle East, too, it’s a good bet that any successful answer to the Islamic State will also be Islamic.)

The point is not that traditional ideas alone can save societies in transition. That way lies ISIS and the foredoomed ruin of countless old regimes.

But the assumption, deeply ingrained in our intelligentsia, that everything depends on finding the most modern and “scientific” alternative to older verities has been tested repeatedly . with mostly dire results. The 19th-century theories that cast themselves as entirely new and modern were the ones that devastated the 20th century, loosing fascism and Marxism on the world.

Which makes Harari’s concluding provocation feel like an unintended warning: “In terms of ideas, in terms of religions,” he argues, “the most interesting place today in the world is Silicon Valley, not the Middle East.” It’s in Silicon Valley that people are “creating new religions” . techno-utopian, trans-humanist . and it’s those religions “that will take over the world.”

He could be right. But if those new ideas are anything like the ones that troubled the 20th century, we may find ourselves looking to older ones for rescue soon enough.