What began as a “throwaway” post on Reddit grew into a bullhorn of a message sounded from seven continents—from 610 cities and a frozen research station at the bottom of the world. On Saturday, untold numbers of citizens who support the idea of free scientific inquiry, and enough public funding to pursue it, took to the streets to tell everyone else on the planet they did.

In some ways, it was that simple. The March for Science, which turned traditional Earth Day celebrations into a kind of celeprotest, was a coming-out party for the STEM set—a chance to showcase a significant, if overlooked, constituency of innovation-makers (and voters) and, at the same time, an opportunity to vent some long-simmering frustrations. In that regard, it was like any protest march, except with intellectually funnier signs: “There is no Planet B,” warned one. “Less division, more mitosis,” pleaded another. And this one—which was magic-markered below a giant parabola—was there, it seems, just to make the math-minded masses snicker: “I was told to bring a sine.”

Though billed and organized as a nonpartisan affair, some in the protest—particularly in the huge centerpiece rally in Washington, D.C.—had a particular protestee in mind—and that, of course, was President Trump, whose efforts to cut funding to the NIH, the EPA, and other science-supporting agencies have been met with stunned outrage by many. But here, too, the signs were more clever than angry: “Mr. President, I know bacteria more cultured”; and “Dear Trump, are you an atom? You make up everything.”

I thought a lot about that smart signage—the flowering of left-brained whimsy in a sea of supposedly right-brained thinkers—as I spent way too much of my Saturday on a Twittertrek of marches around the planet. And I would venture that this undercurrent of cleverness tells us something important about the demonstrations. For the most part, the scientists and science lovers who marched around the world on Saturday weren’t—and aren’t—protesting a specific person, or party, or policy. Even President Trump isn’t their main target. No, they’re taking on a core driver in the human psyche: fear.

The very existence of science is disruptive—because the tool is designed to undercut belief, to challenge both the sacred and the prosaic. The aim of science is disprove the comfortable assumptions of life, not to reinforce them. And since the time of Galileo, it has been seen as a threatening interloper to those in power and to everyday living.

The notion of human-caused planetary warming threatens the status quo, no less than the notion of a solar-centric universe dislodged the consecrated cosmology of the 17th century. The unavoidable message today: Governments, businesses, and consumers can’t keep doing what they’re doing without the risk of having an iceberg float into New York Harbor.

So, too, the latest fruits of science, technology, engineering, and mathematics—from artificial intelligence to self-driving vehicles to advanced robotics—threaten existing industries and the people who work in them even as they promise to create brand new industries and jobs to replace them. No matter that more Americans now work in the solar power industry than do in the production of natural gas or coal: Science is unsettling to millions nonetheless. It’s still frightening. Indeed, it’s hard to overestimate how much.

Which is why, in my view, Saturday’s global March for Science was so effective. The organizers and participants didn’t try to counter fear with stridency. Their antidotes were humor, cleverness, and the celebration of human ingenuity. They understood that one of the most ancient and potent forces of the brain—fear—could be overcome only by its most developed and fertile force: creativity.

And if that failed, they had a backup. As one sign read: “No science, no beer.”

This essay appears in today’s edition of the Fortune Brainstorm Health Daily. Get it delivered straight to your inbox.