Google plagiarism and you will find definitions like “stealing someone else’s ideas” or “literary theft.” Here the emphasis is on the stealing–it’s the original author who is being harmed. I prefer the definition of plagiarism given by Wikipedia, plagiarism is the *fraudulent* use of other people’s words or ideas. Fraudulent emphasizes that it’s the reader who is being cheated, not the original creator. You can use someone else’s words without being fraudulent. We all do this. If you copy a definition or description of a technical procedure from a textbook or manual you are using someone else’s words but it’s not fraudulent because the reader doesn’t assume that you are trying to take credit for the ideas.

In contrast, a student who passes an essay off as their own when it was written by someone else is engaging in a kind of fraud but the “crime” has little to do with harming the original author. A student who uses AI to write an essay is engaging in fraud, for example, but the problem is obviously not theft from OpenAI. Indeed, in another context the same use of AI would not be fraudulent. If I use AI to help write this post, it’s not fraudulent because the primary purpose of this post is not, as it is with a student essay, to warrant the abilities of the author but rather to convey ideas to the reader. How those ideas came to be expressed in words is secondary and sometimes even irrelevant. 

Indeed, using some else’s words and ideas is often how the world progresses. Plagiarism is a type of intellectual property law and I have long argued that IP law has grown too strong. Patents, for example, are often too broad and copyright is too long. Similarly, I was very much in support of Ed Sheeran in the ridiculous copyright case that ate of years of his life. Sheeran used ideas that had previously been used by many others but even if he had sampled, sampling is not a terrible crime. If I write, ‘he went on a wild goose chase’ or ‘it’s a brave new world’ need I credit the author? If an economics professor says ‘a price is a signal wrapped up in an incentive’, well a little credit to Cowen and Tabarrok would be nice, but sooner or later might this phrase not enter the vernacular? Crediting authors of unique wordplay should have a time limit, after which such wordplay becomes part of the common pool of expressions available for all. Crediting authors of boilerplate shouldn’t even be required.

The reason plagiarism has come to be defined more by “literary theft” than by the “fraudulent use of other’s people’s ideas and words” is that it’s much easier to prove when someone else’s words have been copied than it is to prove fraudulent use. A computer can scan the text of millions of documents to discover “plagiarism” but the computer has a harder time saying what is fraudulent. I argued earlier, that if I used AI to write this post it wouldn’t be fraudulent. But what if Marginal Revolution won a Pulitzer for twenty years of high quality writing and this post were give as an example? Well, its a judgement call.

In short, the focus of any charge of plagiarism should not be on whether someone else’s words have been used. The use of other’s people’s words is a necessary condition for plagiarism but it’s not sufficient. The focus should be on whether readers have been harmed by a fraudulent use of other people’s ideas and words. Focusing on the latter will dispense with many charges of plagiarism.