In copyright infringement law, how is 'substantial' defined?

• A. By the quality of originality in what was copied, not the quantity.
• B. By the total amount copied.
• C. By whether the copying was intentional.
• D. By the commercial value of the copied material.

Answer: (A)

Substantial similarity is about the quality and protectable expression that was copied, not how much was copied. Copyright protection covers expressive details, not ideas or facts, so courts look at whether the specific, original elements that are protectable were copied in a way that the combined work remains substantially similar to the original. A small but highly original passage can be substantial because it embodies protectable expression, while copying a large amount of non-protectable material or generic content may not be. That’s why emphasizing the originality and distinctive expression, rather than quantity, best captures what “substantial” means.

The other ideas don’t fit because copying a large portion isn’t automatically substantial if the material isn’t protectable; intent isn’t required for infringement; and the commercial value of the copied material isn’t the test for substantial similarity.