Recently two popular historians were discovered to have lifted passages from other historians' books. They identified the sources in footnotes, but they failed to place quotation marks around the purloined passages. Both historians were quickly buried under an avalanche of criticism. The scandal will soon be forgotten, but it leaves in its wake the questions What is "plagiarism"? and Why is it reprobated? These are important questions. The label "plagiarist" can ruin a writer, destroy a scholarly career, blast a politician's chances for election, and cause the expulsion of a student from a college or university. New computer search programs, though they may in the long run deter plagiarism, will in the short run lead to the discovery of more cases of it.
We must distinguish in the first place between a plagiarist and a copyright infringer. They are both copycats, but the latter is trying to appropriate revenues generated by property that belongs to someone else—namely, the holder of the copyright on the work that the infringer has copied. A pirated edition of a current best seller is a good example of copyright infringement. There is no copyright infringement, however, if the "stolen" intellectual property is in the public domain (in which case it is not property at all), or if the purpose is not appropriation of the copyright holder's revenue. The doctrine of "fair use" permits brief passages from a book to be quoted in a book review or a critical essay; and the parodist of a copyrighted work is permitted to copy as much of that work as is necessary to enable readers to recognize the new work as a parody. A writer may, for that matter, quote a passage from another writer just to liven up the narrative; but to do so without quotation marks—to pass off another writer's writing as one's own—is more like fraud than like fair use.
"Plagiarism," in the broadest sense of this ambiguous term, is simply unacknowledged copying, whether of copyrighted or uncopyrighted work. (Indeed, it might be of uncopyrightable work—for example, of an idea.) If I reprint Hamlet under my own name, I am a plagiarist but not an infringer. Shakespeare himself was a formidable plagiarist in the broad sense in which I'm using the word. The famous description in Antony and Cleopatra of Cleopatra on her royal barge is taken almost verbatim from a translation of Plutarch's life of Mark Antony: "on either side of her, pretty, fair boys apparelled as painters do set forth the god Cupid, with little fans in their hands, with which they fanned wind upon her" becomes "on each side her / Stood pretty dimpled boys, like smiling Cupids, / With divers-colour'd fans, whose wind did seem / To glow the delicate cheeks which they did cool." (Notice how Shakespeare improved upon the original.) In The Waste Land, T. S. Eliot "stole" the famous opening of Shakespeare's barge passage, "The barge she sat in, like a burnish'd throne, / Burn'd on the water" becoming "The Chair she sat in, like a burnished throne, / Glowed on the marble."
Mention of Shakespeare brings to mind that West Side Story is just one of the links in a chain of plagiarisms that began with Ovid's Pyramus and Thisbe and continued with the forgotten Arthur Brooke's The Tragical History of Romeus and Juliet, which was plundered heavily by Shakespeare. Milton in Paradise Lost plagiarized Genesis, as did Thomas Mann in Joseph and His Brothers. Examples are not limited to writing. One from painting is Edouard Manet, whose works from the 1860s "quote" extensively from Raphael, Titian, Velásquez, Rembrandt, and others, of course without express acknowledgment.
If these are examples of plagiarism, then we want more plagiarism. They show that not all unacknowledged copying is "plagiarism" in the pejorative sense. Although there is no formal acknowledgment of copying in my examples, neither is there any likelihood of deception. And the copier has added value to the original—this is not slavish copying. Plagiarism is also innocent when no value is attached to originality; so judges, who try to conceal originality and pretend that their decisions are foreordained, "steal" freely from one another without attribution or any ill will.
But all that can be said in defense of a writer who, merely to spice up his work, incorporates passages from another writer without acknowledgment is that the readability of his work might be impaired if he had to interrupt a fast-paced narrative to confess that "a predecessor of mine, ___, has said what I want to say next better than I can, so rather than paraphrase him, I give you the following passage, indented and in quotation marks, from his book ___." And not even that much can be said in defense of the writer who plagiarizes out of sheer laziness or forgetfulness, the latter being the standard defense when one is confronted with proof of one's plagiarism.
Because a footnote does not signal verbatim incorporation of material from the source footnoted, all that can be said in defense of the historians with whom I began is that they made it easier for their plagiarism to be discovered. This is relevant to how severely they should be criticized, because one of the reasons academic plagiarism is so strongly reprobated is that it is normally very difficult to detect. (In contrast, Eliot and Manet wanted their audience to recognize their borrowings.) This is true of the student's plagiarized term paper, and to a lesser extent of the professor's plagiarized scholarly article. These are particularly grave forms of fraud, because they may lead the reader to take steps, such as giving the student a good grade or voting to promote the professor, that he would not take if he knew the truth. But readers of popular histories are not professional historians, and most don't care a straw how original the historian is. The public wants a good read, a good show, and the fact that a book or a play may be the work of many hands—as, in truth, most art and entertainment are—is of no consequence to it. The harm is not to the reader but to those writers whose work does not glitter with stolen gold.