After Joni Mitchell accused Bob Dylan of plagiarism, the blogosphere exploded and Dylan detractors cheered. Sean Wilentz on why they - and Joni - are wrong.

When Joni Mitchell trashed Bob Dylan in an interview with the Los Angeles Times last week, using words like "plagiarist," "fake," and "deception," the music blogosphere caught fire. In one corner was a beloved singer-songwriter, in the other, a legend, someone who has been described as the supreme poet of rock 'n' roll.

Dylan's defenders shot back at Mitchell, saying she acted like "a petulant child." But Dylan's detractors chortled: At last, a rock 'n' roll heavyweight had the courage to tell the truth about Dylan. "After decades of carefully manicured deification by Columbia Records," wrote the music critic Jonny Whiteside, the time has come "to flout indoctrination and examine Dylan's track record as a Grade-A phony."

It's not clear how Mitchell defines "authentic" or what her definition might have to do with Dylan. That he changed his name from Robert Zimmerman is not exactly news, and it makes him no more deceptive than hundreds of other writers and artists ranging from B. Traven to Judy Garland. Nor do the numerous vocal stylizations Dylan has adopted over the years - imitated, mocked, but never replicated - mark him as a fraud.

The plagiarism charge, perhaps the gravest charge that can be leveled against any artist, is the one that matters, and it is important to look closely and calmly at Dylan's work, if only to see how the charge misses the point of what Dylan has done, especially over the last decade or so.

Dylan would be the first to concede that he has borrowed from other writers and traditional folk and blues musicians from the very beginning of his career. The melody for "Blowing in the Wind" comes directly from an old spiritual "No More Auction Block," and on a New York radio show in 1962, Dylan played a new song, "The Ballad of Emmett Till," and off-handedly admitted that he had stolen the tune from another folksinger, Len Chandler. Only a few folkies complained, and then quickly fell silent - it transpired the complainers themselves had lifted some of their own tunes from others. Dylan's method was fully in line with what Pete Seeger had called "the folk process," borrowing freely from others to create something new.

Case closed. That is until 2003, when alert listeners noticed similarities between a few lines on Dylan's highly acclaimed (and aptly named) album Love and Theft, and the English-language edition of an obscure oral history of a Japanese gangster, translated as Confessions of a Yakuza, by a physician and writer, Junichi Saga, from a small town north of Tokyo. Early appreciations of Love and Theft had noted how much of the album involved reworking earlier melodies and lyrics, including references to Donizetti and Bing Crosby as well as William Shakespeare. But the Yakuza discovery somehow seemed different. A closer look at the album's songs, especially the track "Floater (Too Much to Ask)," showed about a dozen passages from Saga's book that had ended up, without attribution, on Dylan's album. The news became a front page story in The Wall Street Journal and caused the eminent critic Christopher Ricks, normally a defender of Dylan's creative filching, to step back and say that the appropriation was "quite striking." (When informed about Dylan's use of his words, Saga reportedly said he felt honored, not abused.)

Three years later, when Dylan released Modern Times, listeners trawled for arcane references on the new album, and find them they did, including poetic fragments from Ovid and Henry Timrod, the second-rate pro-Confederate Southern poet. Apparently, the literary thievery was bounded by neither time nor space: Even a much-noted shout-out to rising star Alicia Keys in the song "Thunder On the Mountain" turned out to be a rephrasing of the old blues great Memphis Minnie's tribute song, "Ma Rainey," recorded in 1940. And so, even as Modern Times enjoyed huge sales and critical acclaim, earning Dylan two Grammies, it brought renewed clamor in the blogosphere as well as the pages of The New York Times, and suggestions that Dylan wasn't a musical magpie but a plagiarist. And now along comes Joni.

It's a controversy very much of our Internet age. Thanks to the increased sophistication of general-use search engines such as Google, as well as scanning technology and the appearance of literary and musical concordances online, dedicated sleuths can track down Dylan references without having to spend long hours at the library. High-profile cases of plagiarism by journalists, memoir writers, and historians have added to the frenzy.

At the most basic legal level, the charges of plagiarism are groundless. Almost all of the words and melodies that Dylan appropriated passed into the public domain long ago, and are free to use by anyone. Some argue that if Dylan used words and melodies by others on an album of supposedly original material, he ought to find a way to acknowledge as much, instead of claiming those words and melodies under his own copyright. But except for the Yakuza lines, most are isolated fragments - images and turns of phrase - that hardly compare to inventing a past or stealing scholarly research.

According to American copyright law, transforming the meaning of a copyrighted work can constitute fair use, and it seems that Dylan simply jotted down little phrases he found compelling in books and songs, and later used them for very different purposes in his own work. Indeed, Joni Mitchell herself told an interviewer that Dylan had explained to her that this was exactly his work method and how his ideas found spark.

The idea that Dylan is a faker, unless everything he wrote came out of his own imagination - word for word, note for note - is absurd. By those standards, Franz Kafka is an unscrupulous plagiarist as is Aaron Copland and every jazz great. As the music critic Jon Pareles has observed, all art - not just folk art - involves conversations with the past, battening on everything that the artist can find in culture and history rather than pretending that culture and history don't exist. Pristine originality is not just impossible - it is fakery.

This isn't a just matter of law or ethics. It's a matter of the illusions we make in order to live, which is one definition of art. Dylan, an artist, steals what he loves and then loves what he steals by making it new.

Sean Wilentz is a professor of history at Princeton University. His new book, Bob Dylan in America, from which portions of this article are drawn, will be published by Doubleday in December.