Reconceptualizing Copyright's Merger Doctrine

Intellectual Property, Copyright and Trademark and Patents

Article Snapshot


Pamela Samuelson


Journal of the Copyright Society of the U.S.A., Vol. 63; UC Berkeley Public Law Research Paper No. 2763903, 2016


The “Merger Doctrine” is a defense to a charge of copyright infringement. Some ideas can only be expressed a certain way; courts say that the idea merges with the author’s choice of expression. Merger is important in many cases, including those involving software and depictions of nature.

Policy Relevance

The “Merger Doctrine” is a key feature of copyright law. It protects competition and access to information.

Main Points

  • In some copyright cases, the created work includes an idea capable of being expressed only in certain ways; courts say that the original elements of a created work “merge” with the idea being expressed (the “Merger Doctrine”).
  • The Merger Doctrine is often used to defend against a copyright infringement claim; a work to which this doctrine applies cannot be protected by copyright law, because copyright law does not protect ideas, facts, or processes.
  • Merger is available as a defense even when there are several different ways an idea can be expressed, so long as the number of ways in which it can be expressed are limited.
  • The merger doctrine is often invoked in cases involving depictions of nature or functional works like computer programs, but it applies in many other types of cases.
  • The merger defense may be available for “hard” ideas that are “building blocks of knowledge,” but is not limited to such cases.
  • In cases involving computer programs, the courts have held that the process the software performs merges with the language in which it is expressed: facts (such as prices) can also merge with copyrightable aspects of a work.
  • A merger defense is available when the creator of a work makes design choices that limit the defendant’s options; for example, when making software designed to work with other software, the second programmer’s choice of code is determined by the code written by the first.
  • In some cases, the Merger Doctrine overlaps with the idea that a work must be original to be copyrighted, the idea that facts cannot be copyrighted, or the idea that short words and phrases cannot be copyrighted.
  • The Merger Doctrine promotes competition, access to information, and freedom of expression; it also is invoked when a limited choice of expression is required by law, or when it would be inefficient to insist that defendants express themselves another way.

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