Jon Stewart, in this week’s “Healther Skelter” segment of The Daily Show, found that out for himself after his live audience cheered, enthusiastically, the notion of taking Glenn Beck off the air—while, on the video that that audience was watching, town hall participants jeered, vehemently, at the same idea. “While you were cheering,” Stewart said, in his most sardonic tone, “you perhaps missed, on the tape…uh: they were booing. How we’re gonna straddle this thing—I feel like I’m gonna get a groin pull. Are things that simple? ‘Glenn Beck: Yay!’ ‘Turn off Glenn Beck: Boo…’ ‘Football: Yay!’ ‘Soccer: Booo…’ ‘Abbot: Yay!’ ‘Costello: Boo…’”

But, then, the phenomenon we’re witnessing isn’t merely a matter of reduction, not merely a matter of polarization. On the surface, sure, we can attribute the town halls’ demise of decorum to the potent combination of Astroturfing—“Saul Alinsky tactics,” per the latest meme—and classic propaganda techniques: two distinctive influence machines that stifle democratic discussion by alternately silencing it and skewering it. The problem is deeper than that, though. Because we’ve moved beyond merely differing opinions—beyond even fundamentally oppositional opinions—and settled instead upon a much more unsettling proposition: differing facts in the first place.

“One of the problems that I have is that those who get their information from sources like FOX News have a completely different perception and have a different set of facts than those who get their information from MSNBC,” the political message-maker Frank Luntz noted, discussing the healthcare debate in a recent episode of On the Media. Now, Luntz said, “listeners can quite possibly reject everything that I say because their sources are completely different. It’s a real problem, and it actually encourages much more extreme language as people try to play to their base.”

Indeed. What Luntz was describing is a world that is on its way to becoming—to use the phrase used by Farhad Manjoo in his recent book, True Enough—a “post-fact society.” A world that threatens to loosen our hold on the one thing that, regardless of what else might divide us, promised to hold us together: reality itself. Increasingly, Manjoo writes,

our arguments aren’t over what we should be doing—in the Iraq War, in the war of terrorism, on global warming, or about any number of controversial subjects—but, instead, over what is happening. Political scientists have characterized our epoch as one of heightened polarization; now…the creeping partisanship has begun to distort our very perceptions about what is “real” and what isn’t. Indeed, you can go as far as to say we’re now fighting over competing versions of reality. And it is more convenient than ever before for some of us to live in a world built out of our own facts.

Sounds familiar, right? As in: not a doomsday scenario so much as a sober assessment of our current condition? A world of rhetorical rootlessness isn’t a new phenomenon; as Manjoo points out, it’s something that’s been brewing ever since the Web exploded the distribution channels available to both good-faith content producers and more perniciously motivated propaganda-mongers. (And the broader social phenomenon that fueled that explosion—a broad mistrust of “the mainstream media”—has, of course, been brewing since long before the Web came along.) But our movement toward a “post-fact” political landscape is particularly evident in the healthcare debate—a national discourse that, with its murky terms and heated rhetoric, doubles as a kind of propagandistic Petri dish.

Take, again, the town halls—in which so many angry audience members moved beyond the classic political accusation—you’re spinning—to a more pernicious one: you’re lying. While that isn’t, on its own, a novel accusation—citizens, of course, have accused politicians of untruth before, mostly because politicians have given them ample cause to do so—what is new is the blanket nature of the indictment. And the framing of the mistrust not in terms of bias, but in terms of truth itself. I don’t trust you. In other words: It’s not so much that I disagree with you, it’s that I will systematically refuse to believe anything you say. The declarations we’ve seen at the town halls haven’t been, generally, singular allegations; they’ve been broad. (“Everything the State says is a lie,” Nietzsche said, “and everything it has it has stolen.”) And, to a large extent, those allegations haven’t been specimens of reason so much as symptoms, apparently, of inarticulate outrage that has finally found an outlet for expression. “Now don’t you let the government get a hold of my Medicare,” and all that.

Taken together, these expressions of mistrust filter to something even deeper than cognitive dissonance. Call it cognitive dissociation.

Megan Garber is an assistant editor at the Nieman Journalism Lab at Harvard University. She was formerly a CJR staff writer.