This is a photograph by Walker Evans.

And this is a photograph by Sherry Levine.

Walker Evans' photograph dates from 1936, when he was hired by the Farm Security Administration to document the American South in the wake of the Great Depression.

Sherry Levine's was taken in 1981 from a reproduction of the Evans photograph, as part of a series titled yes, "After Walker Evans."

Credit where credit is due, but if forgery is not at issue here, what is?

Evans' photographs are iconic and indisputable documents of the Depression.

They show us its face.

But what exactly do Levine's photographs show us?

Recent art is full of copying of all kinds and degrees.

Art that borrows, steals, pilfers, or poaches existing images.

Some of them iconic, others not.

Are these confessions of creative inadequacy, bald opportunism masquerading as concept?

Are these cries for help as we drown in an image saturated world, or the death rattle of the great pictorial tradition?

How are we supposed to distinguish this kind of copying from a long history of art full of allusions, influences, and innumerable instances of visual sampling, long before hip hop spread the sonic version of it coast to coast.

A sample after all is just one part of a whole song.

But what if the copy is the artwork?

This is the Case for Copying.

Artists, of course, have been copying since time immemorial.

In fact, the earliest Western traditions of aesthetic thought defined art as mimesis, or imitation of the visible world.

But artists don't just imitate the world, they imitate each other.

Copying in order to train their hand or demonstrate stylistic innovation.

They copy to signal the influence of other artworks, to claim the prestige of a particular heritage, or to rework a stock artistic subject for their own time.

Working from existing imagery and traditions can also suggest new ways to navigate history.

Rafael's intimate portrait of Pope Julius the Second became a model for Velasquez's portrait of Pope Innocent the 10th, which in turn inspired Francis Bacon to make over 45 versions of his own, each portrait transgressive in its own time for how it exposed psychological depths of the man at the seat of the church's power.

Velazquez's Las Meninas was also metabolized by Pablo Picasso, who additionally made numerous versions of "le Dejeuner sur l'herbe" painted by Edward Manet in 1863.

Manet's "Dejeuner" in turn borrowed its composition from a Raimondi engraving of Raphael's "Judgment of Paris" and its subject from "Le Concert champetre."

But it's Manet's "Old Musician" that establishes him as the modernist mix master.

Though it might look like a genre painting, the "Old Musician" is in fact a composite image with an extravagant number of citations.

"A painted phrase," as the art historian Carol Armstrong called it, that reads, "'after Watteau,' 'after myself and Murillo,' 'after Le Nain, and Velazquez,'" and so on.

Manet's painting is not a window onto another reality, but a cluster of representations, each one like a song that can be sampled again and again.

Manet's mashup, moreover, stares back at us.

The "Old Musician" personifies the way that all pictures, so to speak, regard us.

Images aren't just neutral depictions of the world.

They're instruments influencing how we perceive ourselves and others.

This awareness inspired a number of artists in the late 1970s to make art that foregrounded representation itself.

Art historians refer to this work as Appropriation art.

In 1977, art critic Donald Crimp curated an exhibition titled, "Pictures," bringing together artists who shared an interest in understanding the picture itself.

Artists of the Pictures generation, as they came to be called, plundered existing images for their own work.

Jacques Goldstein's film "Metro-Goldwyn-Mayer" loops the familiar MGM lion's roar, suspending us between the pleasure of anticipation and the frustrating deferral of the feature film.

Dara Birnbaum's technology transformation, "Wonder Woman," fragments and repeats clips from the TV series to draw out the relationship between technology and sexual objectification.

By isolating and manipulating images, these artists direct our attention toward their subtexts and demonstrate how they get their meanings, not through our actual experience with lions or superheroes, but through our associations with other pictures like them.

In her series of film stills, Cindy Sherman photographed herself in the poses and scenarios of generic feminine personas that evoked stock narratives, so that each version of Sherman seems overdetermined from the start by our expectations for her.

As Crimp wrote, "We are not in search of sources or origins but of structures of signification-- underneath each picture, there is always another picture."

These artists certainly weren't the first to use images from pop culture.

The aptly named Pop Art movement built upon the work of artists including Jasper Johns and Robert Rauschenberg, who made bronze casts of mass produced objects or incorporated newsprint and rubbish into their work.

Art historian Leo Steinberg described this work as belonging to the Flatbed Picture Plane, borrowing the term from the flatbed printing press that had flooded the post-war world with mass media images.

As Steinberg saw it, paintings were no longer doorways to imaginary worlds, evoking our visual.

Experience they were like tabletops, strewn with papers and objects, that simulated how we look at pictures in newspapers and magazines.

Not incidentally Andy Warhol began his career in advertising.

Warhol explained that he chose the subjects of his paintings, from commercial products to celebrities, precisely because everyone already liked them.

The artist's job, so Warhol claimed, was not to offer up new images of beauty, but to reproduce what society had already approved.

This authorized him to appropriate images of mass produced objects, and to turn them out in the studio he called The Factory, blurring the distinctions between artist and factory worker, and between commodity and art.

In more recent years, Richard Prince, who may sit atop the high throne of copydom, described his interest in copying this way.

"Advertising images aren't associated with an author.

They look like they have no history to them, like they showed up all at once.

They look like what art always wants to look like."

Yet, of course, Prince, Warhol, and other pop artists certainly didn't fade into the woodwork.

On the contrary, a Campbell's Soup can is almost synonymous with the name Warhol, a single blown up cartoon frame with Roy Lichtenstein.

Pop art held up a mirror to the ubiquity of mass media.

But a mirror is often the weakest form of critique.

After all, that other thing that looks like it showed up all at once without history, that's the mass produced commodity.

Perhaps it's no surprise then that the art market quickly embraced Pop Art as one more luxury object.

Appropriation art on the other hand, had a very different relationship to popular imagery.

More like certain strands of Dada and Surrealism, Appropriation art sought to understand how images around us inform our psyche and provide a basis for collective life.

Martha Rosler's "House Beautiful-- Bringing the War Home" used a technique similar to surrealist collage, inserting photographs from the Vietnam War into scenes of American domestic life.

Both sets of images were taken from copies of life.

Rosler just reassembled what was already bound together in the magazine, and what only a serious threshold for cognitive dissonance holds apart.

Appropriation art also hearkened back to the "Readymade" by highlighting how an artist's gesture of selection could confer value on the most mundane object.

Like the "Readymade," Appropriation drew attention to the institutions whose operations depend on ideas of exceptionality and originality, even and especially in the face of total unoriginality.

Appropriations by Sturtevant, who made perfect copies of artist's work-- in the case of Warhol, actually borrowing his silk screens to get the job done-- as well as those by Sherry Levine, compel viewers to question just what kind of value is added by a signature, and more importantly, what kinds of people have historically been authorized to sign works in the first place.

Hint, hint-- they've usually looked more like Walker Evans and Duchamp than Sherry Levine or Sturdevant.

Indeed, countless creative achievements in our museums are considered anonymous, many of them seized from regions and social groups that have been denied recognition and representation.

This is to say nothing of conventionally unauthored cultural contributions from quilts, to recipes, to folk or blues songs.

In his essay, "The Death of the Author," the theorist Roland Barthes argued that writing contains many layers of association that can only be unified in the reader's experience of a text.

This meant that the author had no particular authority over the meaning of a book, because anything she wrote existed in a web of connotations and cultural significance.

To interpret a book or an artwork was therefore not to decode it, or to identify its definitive meaning, but to demonstrate how it functioned in this web of significance.

Michel Foucault followed with his essay, "What is an Author?

", which argued that an author is actually just an organizing principle that allows us to group together a certain number of cultural objects.

More importantly, it clarifies who did not make the work, impeding, rather than helping along, the free circulation and inventiveness of creative output.

No less of a paradigm for the artistic genius than Pablo Picasso once said, "Good artists borrow.

Great artists steal."

This is often taken to mean that great artists transform their influences into their own authentic and original inventions.

But Appropriation art turns this meaning on its head.

Appropriation art asks us to recognize that so-called great artists managed to convince us that their works are authentic and original because society has already given them the power to be authentic and original for reasons that have little to do with genius and a lot to do with the structures of power that concerned Foucault.

Yes, there are people who have done amazing things and gotten credit for it.

And we're grateful for their work.

But copying shows that the idea of the original originating genius is a myth.

It shows that this myth is linked to the power of images themselves to determine what kinds of representation, visual as well as political, are made available in our societies.

Appropriation art, while sometimes confounding and often contested, helps us see that the context of pictures is absolutely integral to their meaning.

It reminds us that pictures don't just have histories, they exist in history.

A copy, no matter how perfect, is never really the same as the original, since its context is always shifting.

And since we exist in history, our perspective is always shifting, too.

When artists copy, we recognize that they're making fresh meanings through their interaction with signs and symbols and bits of information already out in the world.

And that this work is never done, not for them, and not for us.