Many people equate plagiarism with copyright infringement, yet these are different issues. Copyright is a technical, legal issue. It’s about ownership of work—whether written, musical, sculptural, or otherwise. If you copy this article, or a substantial portion of it, without permission, and you sell those copies (stop laughing), you’ve violated copyright laws. The same applies to audio, video, and other media. However, plenty of works are not protected by the copyright laws, such as the works of Herman Melville. Nothing published before 1923 is protected. Go ahead, make copies.
While Melville’s work may not be protected by copyright laws, it is entirely possible to plagiarize it. Just try to pass off Moby-Dick as your own and see what happens. Plagiarism isn’t about copyrights, it’s about dishonesty. It’s about pretending someone else’s ideas and work are your own, even if those ideas are paraphrased. (If you paraphrase, you’re no longer committing a copyright violation because copyright protection is about the form of expression, not the idea itself.) Plagiarism can’t exist, however, if you acknowledge your sources: As long as you say where you got your ideas from, it’s just called research. Moreover, it’s impossible to plagiarize common knowledge: You can’t steal the idea that the sky is blue, because everybody already knows that.
[…] Copyright protection is weak when it comes to recipes. The U.S. Copyright Office states, “Mere listings of ingredients as in recipes, formulas, compounds or prescriptions, are not subject to copyright protection.” Explanatory notes—like the paragraph before the recipe where the author reminisces about dinners on the family farm—are protected, but the recipe itself is not. That’s why Colonel Sanders has had to work so hard to keep his recipes a secret.
Plagiarism is another story, though. […]