Notice the artistic principle that's governing what sells: The principle is that there's no longer any principle. The market plunks as happily for one kind of work as for its opposite.

Now look at the world's most important surveys of contemporary art this summer in Europe. Same nonprinciple applies.

In both buying and curating, diversification is preferred to investing deeply in one notion of what matters most in art right now. Trying to take stock of this moment in contemporary art is like doing inventory at Amazon.com: There's something for everyone, times 10 — even quite a bit that's very good — but little sense that some things matter more than others.

ALL DIRECTIONS AT ONCE

The art world's dominant direction is a random scattering.

At the Venice Biennale, veteran curator Robert Storr has put the latest abstractions from German master Gerhard Richter near the folk-art figuration of Cheri Samba, a Congolese street artist. Both are around the corner from a huge, Japanimated video of a doll's house being flooded, which is not far from a sober installation of ephemera and photographs that document the life of Wael Zuaiter, a Palestinian activist and intellectual assassinated by Israeli agents in Rome in 1972.

At Documenta, curators Roger Buergel and Ruth Noack are giving big play to a slew of highly polished minimal sculptures by John McCracken, a 72-year-old American whose career is in revival. But the curators are equally committed, apparently, to a bevy of extra-sloppy, ugly-is-beautiful sex-themed allegories by Australian painter Juan Davila, born in Chile in 1946. You're likely to run into works by either artist sitting near a political video, a solemn black-and-white photo or even an antique Oriental rug.

People used to complain that for any work to have a chance, it had to support the narrow doctrines of the scene's most powerful arbiters — an ubercritic like Clement Greenberg, who once proclaimed abstraction as the only way ahead for art, or a megacurator such as Okwui Enwezor, accused of turning the last Documenta into a political soapbox. No danger of that today. The doctrines seem so meek, almost every kind of art gets equal attention.

Maybe this new, noncommittal attitude is an offshoot of the strange fact that despite all those broken auction records, no one's claiming that many of the latest pricey works will go on to matter deeply in the history of art. In the market, and then spreading like a virus to the art world at large, the idea may be to counter a lack of evident quality and significance by going for quantity and range.

Western society is bound up in the notion of consumer choice. A vast spread of commodities, of any kind, seems as sure a sign of civilization's success as the virtues of any one of them. It has taken a good while, but now fine art, once thought of as a humane antidote to commerce, seems to have bought into that notion, too.

It's as though the market's out-of-control success has made it the model that applies across the board in art.

According to old ways of thinking, the market was supposed to follow where the top end of the art world led, investing in the few artists picked out as important by experts with no money at stake. Today, it's the market that leads. It scatters its dollars here and there, then watches as the rest of us art lovers scamper to see where they have landed. Or at very least, the market watches as others imitate its scattershot approach.

Of course, any decent market is supposed to pay attention only to the price tags it can attach to things, not to the things themselves. It should be an equal-opportunity buyer and seller. What's strange about the current state of the art world is that the market's artistic laissez-faire has spread beyond the salesroom. It's as though curators, too, don't want to commit to where the market — in their case, the market for ideas — ought to be heading.

They put out a pile of varied stuff and hope to find takers for at least some part of it. Triumphant market principles — that variety is good for business; that what sells well is good — seem to take over when there are no bold artistic principles to rival them.

A tour through Documenta or the Biennale feels like a stroll in New York's crowded gallery districts. Some of the artists' names may be different. (Not for long; the galleries will soon pick up the unknowns.) But there's the same confounding range of suggestions for what should count as good.

At Documenta, for instance, curators are pushing the latest sculptures by McCracken — tall pillars or slabs, in slick lacquer or polished bronze, with the simplest of cubic geometries. But if you don't like that version of McCracken — or his 1960s pieces that the new work derives from — why not try another one? For a little while in the 1970s, McCracken made messy, brightly colored mandala paintings that reversed the fundamental principles of the glossy work he'd done before. Those are in Documenta, too, and just as well liked by its curators, apparently, as the rigorous sculptures that stand as their antithesis. Or as the work of radical Argentine conceptualist Graciela Carnevale, who invited unsuspecting art lovers to an opening in 1968, then locked them in the gallery to see how they'd break out. That moment is preserved in photographs that pop up more than once across the Kassel show.

PROFOUND ISN'T SELLING

Of course, there has always been a wide spread of art out there. Rival notions of what art should be, and the curators promoting them, have always vied for our attention and respect. But with this latest round of surveys, it feels as though stiff competition has been replaced with flabby evenhandedness. The old idea that at any given time some kinds of art might mean more than others has been replaced with a notion that anything goes, as long as someone, anyone, gets some kind of buzz from looking at it — before moving on to looking at its opposite.

In Venice, a video of a boy kicking a rubber skull in front of the bombed-out former headquarters of the Serbian army gets the same weight as the daily figurative doodles of a painter from Argentina, which don't seem to matter any more — or less — than the latest batch of two-tone abstractions from the brush of an 84-year-old Ellsworth Kelly. There's a kind of leveling effect that makes even the very best, most innovative work feel like just another option some artist is trying on for size. When you glide painlessly from an engrossing video of a boxer's knuckles coming within a hair of a beautiful woman's face, made by a little-known Belgian named Sophie Whettnall (she's that almost-battered woman), to the imposing welded blobs of the famous Austrian Franz West, it can shake your belief in either one.

The funny thing is, this lack of focus represents a kind of trend, or at least a moment in the history of art that's different from the moments that have come before. This summer's shows suggest that our current absence of direction has brought along its own peculiar tendencies in how art gets made and shown. There's an obsession with the past, given the lack of dedication to any potent view of what we need today; a new focus on good looks, given how well the market has rewarded work that doesn't even try to be profound; a last-ditch attempt, maybe, to fight the market with cerebral art that's barely even there.

Yet all these feel more like the result of our confusion than promising ways out of it.