Glossary
Fair use
A US legal doctrine that allows some uses of copyrighted work without permission, decided case by case.
Fair use is a defense in US copyright law. Courts weigh four factors: the purpose and character of the use (including whether it is "transformative" or commercial), the nature of the copyrighted work, how much of it was used, and the effect on the market for the original.
Many AI companies argue that copying books, articles, images, or music to train models is fair use. Courts have reached different conclusions depending on the facts, such as how the material was obtained and whether the AI output competes with the originals.
A ruling in one case does not settle the question for all AI training. Other countries use different rules, such as narrower "fair dealing" exceptions or specific exceptions for text and data mining.
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