In the climactic sequence of "Invasion of the Body Snatchers," Kevin McCarthy staggers into the road like an Old Testament prophet, waving his arms, shouting dire warnings of pod people. "They're here!" he roars, as the cars' headlights arc around him. "You're next!"

Substitute the figure of culture critic Lee Siegel, and you have a pretty fair picture of "Against the Machine," a brief but highly charged polemic about the Internet's podification of our culture. This isn't to denigrate Siegel's argument but to suggest its rhetorical pitch -- and to question whether he is the right one to make the argument.

Certainly there's no questioning his C.V. According to Wikipedia (an institution he despises), Siegel has been book critic for the Nation, art critic for Slate, staff writer for Talk and Harper's magazines, contributing writer for the Los Angeles Times Book Review, senior editor at the New Republic ... on and on he goes, a culture unto himself, weighing in on all things great and small. He has even managed to have an opinion about baseball caps, which -- I never knew this -- signify "a lazily defiant casualness ... a hopelessness about the possibility of originality ever to fly in the face of hierarchy."

Siegel's Olympian perch began to sag a little in September 2006 when, stung by anonymous reactions to his New Republic culture blog, he decided to pose as a reader himself under the handle "sprezzatura." Slamming all his detractors ("immature, abusive sheep") and dousing the blogmaster with incense ("Siegel is brave, brilliant, and wittier than [Jon] Stewart will ever be ... You couldn't tie Siegel's shoelaces"), author and sock puppet were quickly sniffed out by other readers. Siegel was suspended, and his blog was cast into the ether.

More grievously for someone of his self-regard, he became, depending on the generosity of your perspective, either a laughingstock or a poignant symbol of high culture sucked into the mire of the low. Siegel himself dismissed the episode as a mere "prank." Given more time, he has recast it as a fortunate fall. "In good American fashion," he writes now, it earned him a Deborah Solomon interview in the New York Times Magazine (how many culture critics get that?) and "the opportunity to write the book on Web culture that I'd long wanted to write."

And yet, for all his eagerness to rise above it, his back story dog-ears each page, and the suspicion lurks that this is not so much a vanity project as a wounded-vanity project. Sprezzatura wants to get some more licks in.

And to do it in the guise of public service. Those anonymous assassins, it turns out, weren't just hurting Siegel (and, he reminds us, his mother), they were ripping holes in our cultural fabric. The subtitle of Siegel's book is "Being Human in the Age of the Mob," and it's worth noting the Burkean scowl of that "mob." Siegel may have liberal credentials, but he is making, at bottom, a conservative argument: in favor of gatekeepers and cultural elites, against the cacophony of untrammeled opinion.

In the same way that Edmund Burke regarded the guillotine in the Place de la Révolution, Siegel regards Gawker and YouTube. And when he writes that "the Internet is possibly the most radical transformation of private and public life in the history of humankind," he doesn't mean "radical" in a nice way (any more than Burke did). Bad times are a-brewing. The "borders of truth" are eroding. Knowledge is "devalued into information." Americans are producing, not enjoying, their own leisure. Our interior lives are being "packaged like merchandise," and "the sources of critical detachment are drying up, as book supplements disappear from newspapers and what passes for critical thinking in the more intellectually lively magazines gives way to the Internet's emphasis on cuteness, novelty, buzz, and pursuit of the 'viral.'"

A thinker no longer has any space to think, says Siegel. "Ads pop up, spam comes in. If you are a blogger, you are being linked to. Search engines pick up on what you post. E-mail waits to be opened. You are being asked questions. (Can Pretty Boy Save Boxing? Should Paris Go to Jail? Do You Know Your Credit Score?) Gradually, on e-mail, on your blog, on eBay, on Jdate.com, by hook or by crook, the ghosts in your machine -- other people -- throng closer to you."

And if Siegel isn't willing to exorcise the ghosts, he's willing to get exercised about them. It would be wrong to view his anger simply in personal terms or to deny him a rhetoric commensurate with that anger. For he is, above all, serious about what he does. He believes in the act of criticism, at no small cost, and his most eloquent writing has been a protest against irony in all its incarnations (Jon Stewart, Dave Eggers, Larry David). Irony, after all, is a tacit admission that nothing matters too much, and in Siegel's world, everything matters, and the critic, in some way, matters most of all.

This is an unfashionable proposition, and it is to Siegel's credit that he is so willing to make it. Unlike, say, the New Yorker's Anthony Lane, he's not afraid to make a fool of himself. He leaps without looking, trusting in the safety net of his taste. Which means, of course, he often lands on his ass. (And occasionally crawls up somebody else's. In one article, he likened Oprah to Christ.) All the same, there's nothing penny-ante about Siegel, even when he fails. He ranges widely, he reads closely. The strongest parts of "Against the Machine" are his dissections of Alvin Toffler and like-minded futurists, whose rhetoric has proven all too assimilable with corporate profit.

It's when Siegel has to gather exhibits for the prosecution that he gets in trouble. No one is safe from his "J'accuse." He criticizes Method acting because it made movie actors' faces more accessible and "easily habitable," which is just one step away, it seems, from digitally interacting with them in video games. (The Method never took root in England. Does that mean kids there don't play video games?) An especially large paddle is reserved for Malcolm Gladwell. Not for Gladwell's real offense, which is building castles of pseudo-science in the quicksand of anecdote, but because his book, "The Tipping Point," made popularity the sole criterion for success and, somehow, laid the groundwork for "homo Interneticus." I never figured a book could have that kind of power. If it did, Gladwell would have killed off Mr. Interneticus with "Blink," which privileges instinct over groupthink.

From here, it only gets sillier. We learn that Match.com has taught us how "to perform ourselves, and package ourselves, and sell ourselves to each other." As if the actual experience of dating hadn't taught us. To gauge the Internet's warping of TV, Siegel drags out "American Idol," surely one of our lowest-tech programs (you phone in your votes, for God's sake) and a direct descendant, as Siegel acknowledges in passing, of old-time talent shows like "Major Bowes' Original Amateur Hour."

When he can't find sufficiently subversive real-world examples, Siegel channels "Reefer Madness" visions of purest pulp. "Perhaps your husband is, at this very moment, shut away in his office somewhere in your home, carrying on several torrid affairs at the same time under his various aliases: 'Caliente,' 'Curious,' 'ActionMan.' When he emerges from his sequestered lair, red-faced and agitated, is it because he has been arguing for moderation with 'KillBush46' on the political blog Eschaton, has failed in his bid to purchase genuine military-issue infrared night goggles on eBay, or has been desperately masturbating while instant-messaging 'Prehistorical2'?"

Can you really IM and jack off at the same time? Oh, never mind ... They're here! You're next! And are you any closer to listening? To put it more plainly, if you had to choose someone to preserve civilization from the rabble, would he or she be touchy, impulse-bound and hyperbolic? Or cool, deliberative and Apollonian? In short, would your savior be anything like Lee Siegel?

Any defense of an established culture, if it is to ward off the incursions of the new, must enact the old in some unanswerable way. Through its very performance, it has to cordon itself off from the modernity it's opposing. Siegel's prose, by contrast, draws from the same well of hysteria as the enemy -- most notoriously and least surprisingly when he is writing about the Internet.

On two separate occasions, from his New Republic pulpit, he has linked bloggers to fascism, citing in particular their "hatred of the processes of politics" and their "knockabout origins." "Knockabout origins"? That passes beyond Burke into Burke's Peerage. And outside the Beltway, there aren't many people keener about political processes than Siegel's bête noire, Daily Kos. (It's the processes themselves that Siegel doesn't care for.) None of that has prevented him from proclaiming the blogosphere "hard fascism with a Microsoft face," a coinage he handily compressed into "blogofascism." It's fair to say that, once you've so carelessly flung that tinder into the conversation, you are no longer on the side of reason or culture.

Again and again, Siegel ropes himself with his own lasso. The blogosphere, he warns us, is ruled by a "lust for recognition." A phrase that grows only funnier when you recall Siegel's 2003 Slate diary entry, which consists of the author studying himself -- very closely -- in a mirror. "Lee Siegel, Lee Siegel, Lee Siegel," he chants. "Lee Siegel, Lee Siegel, Lee Siegel." Remember the name now? Just in case you forget, there's a signature gash of red in every Siegel article. Reviewing "The Almost Moon" recently in the New York Times Book Review, he finished off his dissection of Alice Sebold's much-pilloried book by calling it an "insult to the timber industry." That's quite a line; three people quoted it to me within a day of its appearance. But what does it mean, exactly? Wouldn't the insult be to the tree? What of the glue makers? The publishing-software manufacturers? Were they insulted, too? In "Against the Machine," after citing a not particularly reprehensible passage from Internet chieftain Tim O'Reilly, Siegel adds: "If your toaster could write a sentence, it would write one just like that." He gets our attention, yes -- and then the questions resume. Why a toaster? Because it's soulless? Capable of burning the person who uses it? Full of bread crumbs?

Siegel, in other words, has a habit of reaching for the invective nearest to hand, without much regard for the implications. Which places him, cheek by jowl, with the blogo-barbarians pounding on the gates.

There is, finally, an unexamined arrogance in many sociological critiques, and Siegel's is no exception. The Internet, he tells us, is killing off our society -- except for his little corner of it. He alone -- OK, maybe a few of his smart friends, too -- have the taste, character, fortitude to inoculate themselves against the Internet's excesses.

But what inoculates us is not our cultural credentials but the basic exigencies of life. We are too riven, too much in the world to become pod people. We may wince at the same mean-spirited rants Siegel objects to, but most of us find ways to ignore them and incorporate the rest into the weave of our lives -- just as we did with the radio and television, just as we are doing with the iPhone and the iPod. Virtual Land isn't where the majority of us live, not permanently; it's just one of the dozens of course corrections we make between waking and sleeping.

But maybe I wouldn't say that if I were an intellectual. For instance, I see a double latte; Lee Siegel sees end time. "The old-fashioned café," as he recalls it, "provided a way to both share and abandon solitude, a fluid, intermediary experience that humans are always trying to create and perfect." And now? Thanks to our laptops, we are "socially and psychologically cut off from [our] fellow caffeine addicts," deprived of "the concrete, undeniable, immutable fact of our being in the world."

It's the usual Siegel pattern: A prelapsarian fantasy (the days of wine and old-fashioned cafes) gives way to an equally unrecognizable dystopia. At my local coffeehouse, the customers, in between tending to their projects -- dissertations, law-school exams, books, kids -- converse with each other, flirt with the baristas. We crack jokes, we comment on the music. We know each other's names, we ask after each other's families. It is no great challenge to raise our heads from the prosceniums of our laptops. It's why we're there in the first place. Even without the cultural gatekeepers to push us out the door, we've come looking for the flesh and blood, the lived life, of other people.