What is it about the word “art”?

Pronounce it, and the IQ of susceptible folk is instantly halved. (I’ve seen cases where it is diminished by 87 percent.)

Normally sensible people who do not, as a rule, appreciate being made fools of stand idly by as someone tells them that a video of some charlatan climbing naked up a scaffolding while applying Vaseline to sensitive parts of his body is “the most important American artist of his generation.”

Instead of throwing something soft and rotting at such mountebanks, they nod solemnly and reach for their wallets. They are only too eager, when a stiffy arrives from the Museum of Modern Art or some similar establishment, to don the soup and fish and buzz round to the super-exclusive evening event where scores of beautiful people line up to sip the shampoo (David Niven’s word for champagne) and admire a tank full of formaldehyde and a dead tiger shark.

What is it about the word “art” that endows it with this mind- and character-wrecking property?

Why does it induce incontinent gibbering, not to mention mind-boggling extravagance, among normally hard-headed souls?

A full answer would take us deep into the pathology of our time.

It has something to do with what I’ve called elsewhere the institutionalization of the avant-garde, the contradictory project whereby the tics and outré attitudes of the avant-garde go mainstream. The half-comic, half-contemptible result is that ordinary bourgeois adults find themselves in the embarrassing position of celebrating the juvenile, anti-bourgeois antics of people who detest them.

Our misuse of the word “art” also has something to do with our age’s tendency to look to art for spiritual satisfactions traditionally afforded by religion. “After one has abandoned a belief in God,” Wallace Stevens observed, “poetry is that essence which takes its place as life’s redemption.”

That, anyway, is the idea, though exactly what sort of “redemption” may be had from much that goes by the name of “art” today is another question. Consider the case of Millie Brown, the “English performance artist known for her work involving vomiting.”

Yes, that’s right. This deep thinker drinks tinted milk and then regurgitates it over a canvas. That’s her claim to immortality. The Daily Mail in 2013 compared Millie Brown to Jackson Pollock. People — not art people — used to say contemptuously that their child of five could paint something indistinguishable from a Jackson Pollock painting. Perhaps so. Ms. Brown has gone a step further: Her creations are indistinguishable from the “creations” of one-year-olds, whose “canvases” are the products not of their hands but of other organs.

Perhaps the most risible — or is it the saddest? — part of this whole charade is the pretense that there is something novel about what Millie Brown has on offer. “I have an inherent desire to push my own boundaries within my art,” she says.

But we’ve been there; we’ve done that. In 1961, Piero Manzoni produced 90 tin cans of his own excrement. Examples of this limited edition work occupy a proud place in several museums, including the Tate in London. (One tin sold for more than $200,000 at auction.)

And then there was the student at the Ontario College of Art and Design who, in 1996, pushed his own boundaries with an “artwork” that consisted of him vomiting on paintings by others, a Piet Mondrian in New York and a Raoul Dufy at a museum in Ontario.

The truth is that, rhetoric to the contrary notwithstanding, there is nothing new or “challenging” about the “artists” who populate the trendy precincts of contemporary art. All their “shocking” moves were long ago pioneered by Marcel Duchamp and his fellow Dadaists. Indeed, Marcel Duchamp mapped out both large domains of the pseudo-avant-garde. When Duchamp took objects from everyday life — a bottle rack, a snow shovel—and impishly exhibited them as works of art, he pioneered the entire genre of art-as-banality. When he exhibited a urinal as a sculpture, he twitted the more delicate sensibilities of an earlier age with exactly the same sort of naughty schoolboy outrage that (to take but one example) Tracey Emin’s sordid exhibitionism recycled, lo, these many years later. (Pardon, that’s Dame Tracey Emin to you. Yes, really.)

What our latter-day Dadaists have accomplished is simply the domestication and routinization of the avant-garde. They preserve the gestures but lack the spirit. They pretend to be “challenging” or “transgressing” conventional boundaries, but all such boundaries were long ago erased. Far from guying conventional taste, today’s self-styled avant-garde are today’s conventional taste. The only thing these “artists” challenge is our patience. It is a melancholy, not to say tiresome, spectacle. What it says about our culture is partly depressing, partly anger-inducing. The really breathtaking feature of the thing is that these “artists” actually seem to believe they are brave aesthetic and existential pioneers. It’s contemptible, yes, but also quite sad. Curiously, this is something that Duchamp himself recognized when his impish gestures became celebrated by the art world. “I threw the bottle rack and the urinal into their faces as a challenge,” Duchamp noted contemptuously, “and now they admire them for their aesthetic beauty.”