Does beauty still belong in art?

Beauty is no longer about what's pretty, symmetrical, or harmonious. It's about what stirs viewers to grapple with the world as it really is.

Is beauty dead? The answer that springs from much of contemporary art is an unapologetic "yes." Grime, grit, death, destruction, flesh, and flaws have replaced pretty models, still lifes, and pastoral scenes.

In the past 500 years, the opalescent beauty of "La Pietà" has become the urine-soaked effrontery of "Piss Christ." It's no wonder crowds prefer the cheer of Van Gogh's sunflowers to such cheekiness. But history is surely laughing at this irony.

Impressionism, now beloved, was considered an assault on beauty when first exhibited in the 1860s. Critics scoffed that the paintings were sloppy, stupid, and meaningless – the same complaints one often hears about art today. As art critic Clement Greenberg famously said, "All profoundly original art looks ugly at first."

So perhaps it is premature to declare beauty obsolete. Instead, what's needed is a more nuanced appreciation of contemporary art's aesthetic. Today, beauty is no longer about what's pretty, symmetrical, or harmonious. It's about what stirs the viewer to grapple with the world as it really is. Art is not a cosmetic to prettify reality or provide escapist pleasure but a hammer to smash our complacency.

The philosopher George Santayana described beauty as "a living presence or an aching absence." In contemporary art, it's quite often an aching presence. As Peruvian writer Mario Vargas Llosa pointed out, "Contemporary aesthetics has established the beauty of ugliness, reclaiming for art everything in human experience that artistic representation had previously rejected."

This challenge to convention reflects artists' "I cannot tell a lie" honesty. After the savagery of World War I, art turned to the dark side with wrenching paintings of brutality by German Expressionists such as George Grosz, Otto Dix, and Max Beckmann. "We had found in the war," the Dada artist Richard Huelsenbeck said in 1917, "that Goethe and Schiller and beauty added up to killing and bloodshed and murder." After World War II, Theodor Adorno said that "to write poetry after Auschwitz is barbaric."

No wonder today's art reflects an unsettling sense of disturbance. Check out Anselm Kiefer's charred landscapes. Or Lucian Freud's clotted canvases grotesquely exaggerating each crease and fleshly flaw in his models. It shouts: What a broken, saggy, ruined piece of work is man! If we don't want to be blind to reality, it behooves us to look at contemporary art, think about it, register its message, and understand its origins.

"If you look at the street art of Jean-Michel Basquiat or younger artists like Dash Snow or Barry McGee, their work is about the grit and grime of reality," says Susan Davidson, senior curator at the Guggenheim Museum. "There is beauty in it but it's harsher, rough, and in your face."

Morley Safer, who covers art for CBS's "Sunday Morning," says, "It's clear beauty has no place in contemporary art." He suggests substituting "emotional and intellectual impact" as the criterion to judge quality.

To assess quality in today's art, don't rely on superficial beauty. Unlike a vapid Breck-girl image, good art has got to have punch to shake us up, wake us up, and – above all – make us sit up and take notice.

Alejandro Cesarco, an up-and-coming artist in New York, sees a work's surface appearance as merely a door-opener. "It's part of a seduction strategy, an initial stage of allowing somebody into the work, although it never ends there." He adds: "There has to be something that makes you continue to think about the work."

Good art grabs our attention, then deepens our engagement with multiple layers that expand our knowledge of the world and ourselves, and make us see and feel and think in different ways. And all this should come in the form of an object made with consummate skill. "Things that quicken the heart" is how John Baldessari, a master of postmodern art, puts it.

Renaissance idealism – a pinnacle of beauty in visual art – embodied the smiling face of life as we might wish it to be. Caravaggio gave art a Baroque twist when he took his models from the gutter and painted the Virgin Mary with dirty feet. Caravaggio's patrons howled, just as today, museum-goers often recoil from art reflecting the sordid side of life.

It's lovely to depict humanity's highest aspirations, but it's necessary to acknowledge our feet of clay, too.

Looking at art today has the morbid fascination of rubbernecking at a wreck on the highway. Yet the artist's intent goes beyond voyeurism to sound an early warning. The canary's song is beautiful and lulling. But when its melody stops in the mine, you'd better cease heaving that pickaxe and run for your life.

• Carol Strickland is an art correspondent for The Christian Science Monitor and the author of "The Annotated Mona Lisa: A Crash Course in Art History from Prehistoric to Post-Modern." This is the second of a three-part series.