Duration of Copyright and Patent

There is another fundamental difference between most forms of real and personal property and the intellectual property embodied in software. Real and personal property rights generally last forever, but copyrights and patents are temporary ownership rights that terminate with the passage of time.

In the United States, the Constitution mandates that such rights shall be granted "for limited times," a particularly vague provision that allows Congress to define and change the terms of the copyright and patent monopolies, which it frequently does. Current U.S. law provides that, for new works, copyrights last for the life of the author plus 70 years or, for a work of corporate authorship, the shorter of 95 years from publication or 120 years from creation. New patents last for 20 years from the date the patent application is filed.

Upon expiration of the term of a copyright or patent, the intellectual property is said to pass into the public domain. The once exclusive rights of the owners of that intellectual property become available for exercise by anyone who wants them, freely and without charge.

The word freely is used here in a different way than when I was describing software freedom in the open source definition. Freedom under an open source license may be limited and conditioned by the copyright and patent owners. But once intellectual property enters the public domain, its owner can no longer restrict its exploitation and use in any way.

Through the passage of time, the intellectual works of Shakespeare, Mozart, and Newton have long since passed into the public domain. That intellectual property is completely free for anyone to use. But the free intellectual property of Linux and Apache is still subject to the terms and conditions set by the owners of those original works of authorship, because those copyrights have not yet expired .

It is incorrect to suggest that open source licensing destroys intellectual property or is inconsistent with intellectual property laws. Quite the opposite . Open source software is owned by individuals and companies under the authority of the copyright and patent laws. Those owners license their software to the public. It is not public domain software. Or at least, it won't be public domain software until the copyrights and patents embodied in the software expire by the slow passage of time, as specified in the intellectual property laws.