On occasion, PG receives emails or calls from an author who is complaining that someone else improperly stole their idea for a book or story.
Frequently on those occasions, PG explains a fundamental distinction under US copyright law and the copyright laws of many other countries. Copyright does not protect an idea, only the particular expression of an idea that an author creates.
(With apologies to any who may be offended by PG’s Paleolithic gender expression), the story structure of Boy meets Girl, Boy loses Girl, Boy gets Girl can and has been used over and over by many different authors, screenwriters, etc.
Likewise, the book or movie plot structure for a Quest is also unprotectable by copyright.
Following is a more detailed explanation of the Idea/Expression dichotomy.
TRIGGER WARNING: Legalese follows! French, too! (scènes à faire!) You will encounter links to statutes and cases! You are not required to click on links or understand everything that appears below! PG has never given a test on anything and is not about to start doing so now!
Through both court decisions and specific language in the Copyright Act of 1976, the scope of copyright has been limited to particular expression of an idea, not the idea that underlies that expression.
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The specific provision is in Section 102(b):
In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work.
This provision was described by the drafters:
Copyright does not preclude others from using the ideas or information revealed by the author’s work. It pertains to the literary, musical, graphic, or artistic form in which the author expressed intellectual concepts. Section 102(b) makes clear that copyright protection does not extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work.
Some concern has been expressed lest copyright in computer programs should extend protection to the methodology or processes adopted by the programmer, rather than merely to the “writing” expressing his ideas. Section 102(b) is intended, among other things, to make clear that the expression adopted by the programmer is the copyrightable element in a computer program, and that the actual processes or methods embodied in the program are not within the scope of the copyright law.
Section 102(b) in no way enlarges or contracts the scope of copyright protection under the present law. Its purpose is to restate, in the context of the new single Federal system of copyright, that the basic dichotomy between expression and idea remains unchanged.
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The law at the time of the passage of the Copyright Act of 1976 regarding copyright protection for expression but not for the underlying ideas or any functional aspects of the work, comes primarily from two Supreme Court cases. In 1879, the Supreme Court decided in Baker v. Selden that the copyright of a book that described a particular bookkeeping technique did not protect the forms necessary to use the technique.
There is no doubt that a work on the subject of book‑keeping, though only explanatory of well‑known systems, may be the subject of a copyright; but, then, it is claimed only as a book. Such a book may be explanatory either of old systems, or of an entirely new system; and, considered as a book, as the work of an author, conveying information on the subject of book‑keeping, and containing detailed explanations of the art, it may be a very valuable acquisition to the practical knowledge of the community. But there is a clear distinction between the book, as such, and the art which it is intended to illustrate. The mere statement of the proposition is so evident, that it requires hardly any argument to support it. The same distinction may be predicated of every other art as well as that of book‑keeping. A treatise on the composition and use of medicines, be they old or new; on the construction and use of ploughs, or watches, or churns; or on the mixture and application of colors for painting or dyeing; or on the mode of drawing lines to produce the effect of perspective, would be the subject of copyright; but no one would contend that the copyright of the treatise would give the exclusive right to the art or manufacture described therein.
In 1954, the Supreme Court restated the principle that copyright protects expression, but not function. In Mazer v. Stein, the Court addressed the scope of copyright protection for a sculpture that formed the base of a lamp. They found that the artistic aspects of the sculpture were protected by copyright, but not the functional aspects associated with being a lamp base:
Unlike a patent, a copyright gives no exclusive right to the art disclosed; protection is given only to the expression of the idea – not the idea itself. Thus, in Baker v. Selden, the Court held that a copyrighted book on a peculiar system of bookkeeping was not infringed by a similar book using a similar plan which achieved similar results where the alleged infringer made a different arrangement of the columns and used different headings. The distinction is illustrated in Fred Fisher, Inc. v. Dillingham, when the court speaks of two men, each a perfectionist, independently making maps of the same territory. Though the maps are identical, each may obtain the exclusive right to make copies of his own particular map, and yet neither will infringe the other’s copyright. Likewise a copyrighted directory is not infringed by a similar directory which is the product of independent work.
The test of whether something is an unprotectable idea or protectable expression is inherently ad hoc, and bodies of law have been developed through court cases for different types of copyrighted works. But there are a number of themes that run through most idea-expression analyses.
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When there are only a limited number of ways that a concept or idea can be expressed, there is little difference between the idea and its expression, and it is therefore said that the two have “merged.” When this happens, the limited number of ways of expressing the idea are not entitled to copyright protection because, in essence, that would be protecting the idea, something outside the scope of copyright. The merger doctrine means that even if things are substantially similar, or even identical, there might not be a copyright infringement.
Another factor is whether the expression is something that you would expect to find in a work on a particular topic or expressing a certain concept. For example, scenes of soldiers marching would be common in many war movies. Such common elements are called scènes à faire, or stock incidents. In a copyright case regarding computer displays, the use of overlapping windows was found to be a stock aspect of windowed displays and therefore not protectable by copyright.