[Reading] has the distinct drawback that, if indulged in to excess, it almost always destroys the precious illusion of the originality of one’s own insights.
—Professor Charles L. Black, Jr.
What Is Plagiarism?
Generally, plagiarism is making use of other people’s words or their ideas without sufficient acknowledgment. If you make use of someone else’s ideas, i.e., if someone else’s ideas are the source or origin for something you have written, then you owe that author a complete citation, i.e., a citation providing sufficient information so that your readers can find the source. If you make use of someone else’s words, you must surround their words with quotation marks and also use a complete citation. It is a simple rule.
Still I think there are a few outlier and difficult cases which are worth thinking about.
Case I. What If Your Source’s Author Is Idiosyncratic?
To whom is owed the duty to cite? Is it owed to the author of your source or to your readers? If the former, then that author might not want to be cited. He may be embarrassed by his prior writing and not want it flagged anew to the public. Alternatively, your source’s author may not like you or your writing, and not enjoy seeing his own “good” work appearing in your “bad” work. Here too, he may prefer not to be cited. He might even give you an express release! Finally, your source’s author may like you and your writing, and wish to be helpful by allowing you to enjoy a bit of (undeserved) goodwill among your readers. Again, in such circumstances, your source’s author may prefer not to be cited. What to do?
Case II. The Wholly New Context.
Another problem sometimes happens when you use someone else’s phrase, sentence, paragraph, etc in an entirely novel way or in a context entirely divorced from the original author’s. Is a citation strictly owed in such circumstances?
In his 1968 Rivers of Blood speech, Enoch Powell wrote: “I can already hear the chorus of execration.” “Chorus of execration”—my lord—a truly unforgettable turn of the phrase. It is not found, as far as I can tell, in the Bible or in any standard translation of the classics. It was used many years prior to Powell by F. Scott Fitzgerald, and also prior to Fitzgerald, by Arthur Conan Doyle. I have no reason to think Powell (knowingly or, even, inadvertently) lifted this phrase from Fitzgerald or Doyle or from anyone else, but even if Powell had done so, his using this phrase was in a context entirely removed from these prior authors. Moreover, putting a citation in a live speech, or even at its end, would really interfere with the flow of the speech. In such circumstances, is a citation strictly owed? Would it matter if Powell had reproduced the speech—and its memorable phrase—in a book of collected speeches?
Case III. The Fool And The Damned Fool.
Now let’s say you’ve read a paper by Professor Alpha on a subject which you had already given a good deal of consideration. Alpha’s paper says “X is true because Y.” If prior to reading Alpha’s paper, you had also come to the conclusion that “X is true because Y,” and then you proceed to write in your own paper “X is true because Y,” do you owe Alpha and his paper a citation? I think many, perhaps most, would say “yes,” but I do not think it is quite so clear. You are not lifting someone else’s idea—the idea is also (ex hypothesi) your own, although Alpha published first. If you came to the idea independently, then Alpha is not your source.
You might not owe Alpha a citation in such circumstances, but you would be a fool not to cite Alpha. You may know that you independently came up with the same idea, but Alpha and his colleagues may not. Even worse, Alpha and his colleagues may believe you, but there may be someone in an entirely different field who does not like you or who, perhaps, makes a living finding (or has an active professional sideline involving) cases of plagiarism. Anyone can allege plagiarism, not just the uncited author.
There are other good reasons you should cite Alpha, not just self-preservation. Kindness. Alpha may want and/or need the citation, and what does it really cost you to cite Alpha? Frequently, authors like to be cited: this includes junior authors, particularly those seeking an academic position, or those already in academia who are undergoing review for tenure or promotion. Such authors are often very grateful, and they will sometimes try to cite you in turn (or return).
Now everything I said above applies to the arts and sciences, but it applies even more strongly to those who write about law. In law, the best way to kill an idea is to claim that it is original or new. If you want to promote “your” idea, then give it a (deserved) heritage or genealogy. If other people independently came up with the same idea as you, then you are killing your own idea if you fail to cite them. Moreover, giving others fair credit builds up your credibility with your audience, as does adherence to professional standards in general.
Above, I suggested that only a fool would fail to cite Professor Alpha. But if the subject matter is law, then I suggest that only a damned fool would fail to cite Alpha.
Case IV. What If You Have Two Independent Sources For A Proposition?
Suppose Professor Alpha in his paper wrote:
“X is true because of Y.”
And Professor Beta in her paper also wrote:
“X is true because of Y.”
Now you decide to write your own paper, and in it, you write: “X is true because of Y.” The idea is not your own. Because the idea is not yours, you need a citation. So which paper do you cite: Alpha’s paper or Beta’s paper? You can cite either or both.
If you cite only one of the two, how do you decide which? You have much leeway here: you could flip a coin, you could cite your friend, the first of the two to be published, etc. If one of the two papers is better known in regard to the particular proposition being cited, then perhaps you should cite that paper. I would think that principles of fair play—although not absolutely mandatory—should push you in the direction of citing the source that was the greater influence on your thinking in regard to the cited proposition.
Again, you have some choice here. But there is a limit. Let’s say that you have not actually read or examined Beta’s paper. Instead, you only know about Beta’s position because many, many third-party sources ascribe it to her and quote her paper. You might have 100s of such third-party sources ascribing this position to Beta, if not actually quoting Beta. Here, the bottom line is that you must quote Alpha, and not Beta.
You can only cite what you have seen, and here, you have not actually seen Beta’s paper. Sure you could quote the third-party sources which in turn quote Beta. But you cannot cite directly to Beta’s paper because you have not seen Beta’s paper. A citation indicates that an idea is not yours. But a citation also indicates that you have read and examined the source cited, as opposed to some other source that purportedly says the same thing. If you have not actually read and examined a source, you ought not pretend that you did. Such a citation lacks transparency, truthfulness, and candor.
It is also unsafe to trust that the third-party sources got it right (or were themselves truthful).
Imagine if you had read Professor B’s book, and B is later, much later unmasked as a fraud, i.e., a person who quotes and cites to nonexistent sources. But before B is unmasked, you innocently read B’s book. Now if B’s book had said “source X stated that ‘Y is true’.” You might have thought that you had a choice between: (1) quoting B’s book for the proposition that source X stated that “Y is true”; or (2) quoting source X directly for the proposition that “Y is true.”
You might think that the second choice is simpler. It imposes less on the reader, and makes your writing crisper. But your putting forward such a citation is not truthful. It is not truthful because the source you have cited is not the one you have seen, examined, and relied upon. It is not truthful because you have not given credit to the actual source you have seen, examined, and relied upon—thereby denying your readers the opportunity to verify your actual source. Moreover, such a course of action is imprudent. If you lift Professor B’s words or ideas, and B is in error or untruthful, then you become a party to B’s wrong. If B is a liar (because source X does not exist), then your citing directly to source X makes your conduct wrongful too.
There is a happy confluence between doing the right thing and doing the prudent thing: you can only cite what you have seen (and examined).
PS: My co-bloggers do good work. So, please have a look around New Reform Club.
Twitter: https://twitter.com/SethBTillman ( @SethBTillman )
My prior post is [here]: Seth Barrett Tillman, Metrics from the Social Science Research Network on Irish Law Departments (including Tillman’s department) (Apr. 3, 2016, 5:45 AM).
 Charles L. Black, Jr., Some Thoughts on the Veto, 40 L. & Contemp. Prob. 87, 88–89 (1976).
 I am sometimes cited by other authors, who go on to state that my position is incorrect. I should hope no one hesitates to cite me in such circumstances. Cite me as correct or cite me as incorrect—I really do not care—just spell my name and my papers’ titles correctly!
 If at the end of a trial, a criminal defendant’s attorney used (John Mortimer’s) Rumpole’s standard closing speech, should the attorney flag his source to his client, the Court, and/or to the jury (if there is a jury)? See, e.g., John Mortimer, Rumpole and the Penge Bungalow Murders 196–97 (2004).