A person may own three kinds of property: real property, such as land or buildings; tangible property, including anything that can be touched but is not permanently attached to land; and intangible property, which can be owned and has value but cannot be touched, such as goodwill and customer loyalty. Copyright is an intangible property interest held by creators of artistic works.
Intellectual property is the value of creative works that arise from an innovative, inventive mind. Industrial intellectual property includes inventions, manufacturing processes and industrial design. The right to benefit from industrial intellectual property can be protected by patent and trademark law. Creative intellectual property includes cultural, literary and artistic works like books and plays, films and photographs, and paintings and sculptures. The rights of the person who develops creative intellectual property are protected by copyright law as soon as the creative work becomes fixed in a tangible medium, like a sketch or digital file outlining a novel-in-progress. Intellectual property rights are protected by law to allow people with creative minds to benefit from their works, which encourages them to develop more creations that benefit the economy, consumers and society.
Tangible objects like books, photographs and theatrical scripts are subject to copyright protection, but the intangible intellectual property rights of the copyright holder are separate from any physical object. The owner of a physical book may resell that book at a tag sale or destroy it by tossing it down a garbage chute, because those acts are among the tangible property rights held by the person who owns the object. The owner of a physical book, however, may not photocopy it, sell the rights to publish it or create a movie script based on it, because those intangible rights are held by the copyright holder. A copyright holder has a legal monopoly on publishing and performing her original creative works and creating derivative works, like a sequel or film.
The value of a copyright is not the value of a specific item but rather the value of the intangible right to do profitable things with the creation, such as license it or duplicate it for sale. Other legal rights reserved to the copyright holder include the right to publicly display or perform a work and prepare derivative works based on the original work. Like other intangible intellectual property rights, copyrights can be sold or donated. A copyright holder may sell all her rights in a creative work or only specific rights, like the right to publish an article in English in North America. The value of that copyright depends on many factors, including the potential income to be derived from use of the copyright and the duration of the copyright being transferred. Most copyrights on works created since 1978 last for the life of the creator plus 70 years. The copyright holder can only transfer the remaining duration of the copyright, so its value will diminish as time passes.
Copyright infringement is a violation of intangible rights, such as the right to copy or perform a creative work. Performance of a musical work or a play without the copyright holder's permission does not comprise the theft of tangible property; the copyright holder may still possess the tangible score, script or recording that contains a representation of the work protected by copyright. But performing the song or play without permission violates the copyright holder's intangible right to maintain exclusive control over public performance and undermines the copyright holder's ability to profit from the works of her creative mind.