“Criticism, comment, news reporting, teaching, scholarship, or research.”

Judicial Interpretation: Non-exhaustive preamble list establishing favored categories of public-benefit secondary uses.

“Whether such use is of a commercial nature or is for nonprofit educational purposes.”

Judicial Interpretation: Dominated by the 'Transformative Use' test (Campbell v. Acuff-Rose; Warhol v. Goldsmith) evaluating whether the use alters the original with new expression, meaning, or message.

“The nature of the copyrighted work.”

Judicial Interpretation: Draws lines between highly creative fictional works (thicker protection) versus factual, informational, or functional works (thinner protection).

“The amount and substantiality of the portion used in relation to the copyrighted work as a whole.”

Judicial Interpretation: Evaluates quantitative proportion and qualitative importance (the 'heart' of the work). 100% ingestion is permitted for non-expressive computational mining (Authors Guild).

“The effect of the use upon the potential market for or value of the copyrighted work.”

Judicial Interpretation: Measures commercial substitution and market displacement versus legitimate transformative market emergence (Sony; Campbell; Warhol).