Let no one else's work evade your eyes
Remember why the good Lord made your eyes
So don't shade your eyes
But plagiarize, plagiarize, plagiarize —
Only be sure always to call it please "research".
Plagiarism is when you take another person's work and try to pass it off as your own. In academia, the definition tends to be more technical — it's when you discuss another person's facts or theories without properly citing them, which is tantamount to passing them off as your own. Around here, though, we're more concerned with literary plagiarism — i.e., taking another person's creative work (or parts thereof) and passing it off as your own.
Literary plagiarism is often used as a plot point, as described in our trope on the subject, Plagiarism in Fiction. However, this Useful Note will attempt to dispel some of the misconceptions people have about plagiarism in real life. Not all plagiarism is the same, and it's rare to encounter "blatant plagiarism", or the exact text copy-pasted from another work but passed off as one's own. There are many different, more subtle ways to plagiarize, and many more different ways to skirt that line but not cross it.
Every work is influenced by what has come before
Literary plagiarism can involve lifted text, characters, or ideas — the text need not be exactly the same if the story elements are so remarkably similar. But just having similar tropes as another work doesn't necessarily mean plagiarism; all stories are influenced by what has come before, and all works are to some degree inspired by what the author has read previously. The two works may even be inspired by an even older common source. Mere inspiration isn't enough for plagiarism; you'd have to take credit for the original idea.
Star Wars is a good illustration of this. A story about a farmboy who rescues a princess and destroys the Big Bad's Doomsday Device is not necessarily plagiarism if the rest of it is sufficiently different from Star Wars. The characters, story beats, settings, and dialogue could all serve on a unique take on the same story — all you could say in that respect is that both works make use of the same tropes. And indeed, George Lucas did exactly this in creating Star Wars himself; the work is a Genre Throwback and borrows a lot of its tropes and conventions from old Flash Gordon serials and Akira Kurosawa films.
Different degrees of borrowing
A Shout-Out is generally the least controversial; it's only a brief reference to another work that rarely lasts longer than a couple of seconds. A Shout-Out is not plagiarism because it's clear from the context that the person knows the reference is not his but wants to acknowledge what came before. This allows a Shout-Out to be directly lifted from the source work (the exact same line, blocking, facial expressions, scenario, etc.).
An homage is more difficult to defend; in general, it will use imagery and ideas from the original material, but with sufficient differences as to be its own work. This lets the viewer easily see that the work is influenced by what has come before. For example, the fifth installment of Stephen King's The Dark Tower series sees the heroes defending a town from raiders who attack every so often, a Whole Plot Reference to both Seven Samurai and The Magnificent Seven. But the characters were original, the setting and the raiders were largely the product of King's own imagination (with numerous shout outs), and the series itself acknowledged the similarity.
A remake or "retelling" is more explicitly the exact same work, but done by a different person in his own way. The way to get away with this is to be open about your intentions, and to seek permission from the original author. A famous example of a retelling that works is John Sturges' The Magnificent Seven, which had the same plot and even some of the same dialogue as Akira Kurosawa's earlier Seven Samurai — the only real difference is that while Kurosawa's film was set in feudal Japan, Sturges' was set in The Wild West. It wasn't plagiarism because Kurosawa knew what Sturges was doing and gave his approval, and Sturges never pretended it was his; he openly acknowledged that he was simply moving Seven Samurai to the Old West. Compare this to Sergio Leone's A Fistful of Dollars, which is a frame-for-frame remake of Kurosawa's Yojimbo but set in Texas. When Kurosawa saw the film, he wrote to Leone, "It is a very fine film, but it is my film."
Finally, a parody is the hardest to defend against accusations of plagiarism, because parodies tend to lift as much as they can from the source material to make fun of it. Internet parodies in particular disclaim their claim to the original work and will often point out the real rights holder in an I Do Not Own sort of way. Yu-Gi-Oh! The Abridged Series and its imitators do this Once an Episode, codifying the convention for The Abridged Series, which tend to lift the clips and some dialogue directly from the source work. On TV or film, a parody generally has a sufficiently different plot and dialogue to technically count as a different work.
Plagiarism in music
Plagiarism in music is a far trickier issue, as there are plenty of songs and acts that look or sound similar to others.
In music, a Shout-Out is generally a welcome convention; it's almost never seen as plagiarism, especially if the artist is doing an obvious tribute to what has come before. And a Cover Version is almost always treated as a Shout-Out, as long as it's properly introduced and labeled as a cover and the covering artist isn't making any money off it without the original artist's permission.
Sampling, the replaying of a riff or section but not an entire cover, is more complicated. Generally, direct sampling is not plagiarism if it only makes up one portion of the song and permission has been sought and given. It's more acceptable if the sample is from a public domain source, which is why so many of them come from things like news broadcasts.
Remixing can be considered plagiarism, if it's done poorly enough that the song isn't changed in any appreciable way, or if it's done without permission and for financial benefit. But it's difficult for a remix to be so similar to the original as to be plagiarism; many remixes will change instruments, rhythm, which bits loop, and other elements so as to be distinct from the original.
Conversely, it can fall into dubious territory if an original song has too much in common with an existing one, as George Harrison learned the hard way when his song "My Sweet Lord" was found to be so closely identical to The Chiffons' earlier hit "He's So Fine" that a court ruled he had to split his royalties with them. (In an extra bit of Paranoia Fuel for songwriters, Harrison claimed he had never intended to rip off the Chiffons' tune, making it a case of what was called "subconscious plagiarism.")
The musical version of an homage is where the artist chooses to be an expy of another artist's appearance or style; it's generally not considered plagiarism, unless the artist claims to have invented that appearance or style himself and it's such an exact copy as to be no different from the original.
Parody in music tends to follow the same lines; a musical satire or parody is generally so obviously such, it's rarely considered plagiarism unless it's impossible to tell that it's supposed to be a parody.
True actionable musical plagiarism generally arises from not crediting samples or remixes, entirely mimicking someone else without any of the above-mentioned defenses, lifting musical passages or lyrics note-for-note without permission or credit and claiming them to be your own (e.g. if you claim you personally wrote the guitar solo in "Eruption" or the lyrics to "Imagine"), or giving your band or act the exact same name as another one.
Plagiarism versus copyright infringement
A big reason for the misconceptions surrounding plagiarism is the tendency to confuse it with copyright infringement. While they often occur hand-in-hand, they're not the same thing. Copyright refers to an artist's right to make money from the work, and if you're making money from someone else's work without their permission, they can sue you to recover the money and stop you from doing it. Plagiarism is an ethical consideration; rather than a question of who makes money from the work, it's a question of who deserves artistic credit for it. It's true that they share certain elements in determining whether they have occurred (how similar the story elements are, whether permission was given, whether it's clearly a parody, etc.), but the consequences are different.
The difference is even if you acknowledge that the work isn't yours or copy someone else unwittingly (and thus avoid technically plagiarizing), you could still be committing copyright infringement if you don't have permission from the holder. Going back to the A Fistful of Dollars example above, Leone plagiarized Kurosawa because he never acknowledged he was copying from him; Kurosawa successfully sued Leone for copyright infringement because he never asked for permission or paid for the rights. On the other hand, it's entirely possible to plagiarize without committing copyright infringement if you're copying a work in the public domain; while publishing a play copied from a William Shakespeare anthology is not copyright infringement, it is plagiarism if you try to pass off Shakespeare's writing as your own.
Copyright law includes protections such as Fair Use for parodies and homages that don't require direct permission from the copyright holder. That said, in some circles it's still considered unethical to do so without some degree of permission from the original author. This is exactly what artists like "Weird Al" Yankovic do; although they might legally be allowed to write their parodies without permission from the copyright holder, they might seek the artist's permission anyway as a courtesy and acknowledgement of who deserves the original credit (not that it's stopped them from making a parody when permission is refused).
Similarly, it's entirely possible to violate copyright law unwittingly, which isn't technically plagiarism because the copying artist wasn't aware that his idea was already used somewhere else. You see this with musicians who choose a name already used elsewhere; for instance, X Japan had to add the "Japan" moniker because of an existing American band called X, and Versailles was forced to change names to avoid confusion with a French artist of the same name.
And because copyright infringement involves monetary culpability rather than moral culpability, a lot of things that technically infringe on copyright are allowed to slide because the infringer isn't doing any real monetary harm to the rights holder. This is how most Fan Fiction is allowed to exist; it's not the I Do Not Own headers that many of them have (although sometimes they're used to head off accusations of plagiarism), but the mere fact that these authors make no money from the work that keeps them from being sued.
(Note that the above paragraphs don't apply if your jurisdiction recognises moral rights or punishes unfair competition; especially with the former, there is a greater possibility that a broader spectrum or even all cases of plagiarism will be punished as copyright infringement, as moral rights protect non-economic interests - they are the personality rights as specific to the author, and they protect, among others, the right to be credited to one's work and the right to the integrity of one's work, which are the most important rights in this case. In other cases, doctrines such as the U.S.'s substantial similarity may apply here.)
Academic plagiarism as it informs literary plagiarism
Many people are introduced to the concept of plagiarism in academia; however, academic works and literary works have very different ends, so plagiarism as it is defined here tends to have more serious consequences in academia than it does in art (where copyright infringement is the heavy hitter). In school, it is considered intellectually dishonest to use someone else's work and pass it off as your own because you're being judged on it; you're getting a grade for how well you write, how well you can organize and formulate your ideas, and how good your conclusions are, so if you're copying from someone else, you're not being judged on your own merits. The consequences for a student caught plagiarizing in college are serious and often include expulsion. And in research, it's considered bad form to use too many of your own ideas anyway; citation is a way of telling the reader, "I didn't pull this out of my ass; other people have said it first, and I'm just reporting what they're saying." In other words, plagiarism is bad in that respect because it asks the reader to trust that you're a genius who knows everything. Students and researchers who are aware of this occasionally suffer from "plagiarism paranoia", or the idea that they haven't cited their work enough to avoid accusations of plagiarism.
In artistic endeavors, though, creativity is encouraged and rewarded. People like to see artists come up with things from whole cloth; they're there for enjoyment and entertainment more than for science and future citation. Plagiarism is thus an ethical consideration; if you pass off someone else's work as your own, you're covering up your own deficiencies as an artist and taking credit for someone else's accomplishment. The problem here is that it's difficult to define originality in art, as everything is based on what came before, so it's impossible to create something that nobody's seen before. If nothing else, almost all the tropes will have been used elsewhere in a previous work somewhere, and The Tropeless Tale is generally accepted to be impossible. So if you're worried about plagiarism, just remember to provide credit where credit is due and change enough of the original work to make it distinct. And if you're worried about unwittingly copying someone else, there's a great line from C. S. Lewis:
- Even in literature and art, no man who bothers about originality will ever be original: whereas if you simply try to tell the truth (without caring twopence how often it has been told before), you will, nine times out of ten, become original without ever having noticed it.
Plagiarism, citation, and This Very Wiki
Here on TV Tropes, we are (kind of) a creative endeavor, and so there is work you can do as a Troper to avoid accusations of plagiarism yourself. That said, we're not exactly making a literary work here; many of our requirements are for academic reasons or to avoid copyright infringement.
We don't require formal citations like Wikipedia does in the middle of the article. But that's because when you're writing a trope example and you link to the work it appears in, that link acts as a citation in and of itself. It tells the reader that if he reads/watches/listens to the work, he'll find what you describe. This is why we like better outside citations to certain Real Life examples and why we don't accept examples from Unpublished Works on trope pages; the former doesn't point to something specific to look for, while the latter is not a citation because the work doesn't exist for anyone to verify the trope's existence. That said, you'll find a lot of uncited real-life examples and whole essays done in a conversational rather than academic style here, which might be fun to read but not necessarily useful.
We also don't like people copying and pasting text from Wikipedia or other sites to TV Tropes, partly out of plagiarism concerns; it's considered bad form to just lift something from elsewhere and pass it off as our own work. TV Tropes has its own style, and we encourage Tropers to write about that information in that style in their own words, even if you can find the exact same information elsewhere.
Finally, as a meta-consideration, please do not link to this page to accuse something else of being plagiarism. It's not meant for Complaining About Shows You Don't Like. And do not add any further examples to this page. It's a Useful Note which is designed to define plagiarism and how it affects what we do here, not a way to name and shame bad artists. Examples of in-universe plagiarism go on Plagiarism in Fiction, not here.