- The GPL Bargain
- Copyleft and Reciprocity
- Policy Objectives
- The Preamble to the GPL
- GPL as Template
- The GPL Applies to Programs
- Linking to GPL Software
- Copyright Law and Linking
- The LGPL Alternative
- GPL Grant of License
- Access to Source Code
- "At No Charge"
- Other Obligations in the GPL
- The GPL and Patents
- Accepting the GPL
The Preamble to the GPL
Richard Stallman and Eben Moglen, the authors of the GPL, write eloquently in the GPL's preamble about their primary objective in creating the license:
The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free softwareto make sure the software is free for all its users. (GPL Preamble.)
Eloquence, by the way, and discussions of public policy, are extremely rare in licenses; attorneys will recall no other such example from their law school courses in technology licensing. That is one feature that stands out about the GPL. It was the obvious intention of the authors of the GPL to arouse licensors and licensees to a higher purpose than the mere distribution of software. Strong and convincing language was called for. It is thus perhaps not surprising that some of the harshest critics of the GPL, and many of its most fervent admirers, point to the preamble to that license when engaging each other in political debate about free software.
The preamble, of course, is not an operative part of the GPL license. It is not among its terms and conditions. There is nothing in its words that must be obeyed. It is merely a helpful preface so that you can better understand the GPL in its context.
The preamble proceeds to define free software:
When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things. (GPL Preamble.)
You will note that this is a shorthand definition of software freedom, shorter even than the definition on the Free Software Foundation website quoted in the first chapter of this book. This paragraph from the license is not the authoritative definition of free software. Unfortunately, arguments about precisely what free software means have engaged the open source community and perplexed the public for some time now. This additional definition in the preamble to the GPL doesn't help.
The next paragraph foretells the reciprocity bargain of the GPL:
To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it. (GPL Preamble.)
This paragraph is particularly interesting. It subtly transforms what had previously been a focus on freedom to a statement about rights. It suggests to me a number of questions that have no easy answers, at least within the four corners of the GPL license or its preamble: How does a freedom become a right? Whose rights are being protected by the GPL, and from whom? Who is trying to deny you those rights, and who has the authority to forbid them from doing it? Can someone make you surrender a right simply by asking? Do the GPL restrictions effectively protect you from those awful prospects? Why do you have to incur responsibilities to protect your own rights?
The fact that these questions have no ready answers points out once again why preambles are bad in licenses. Preambles are not helpful, and they potentially confuse. They are too brief and too ambiguous to guide in the interpretation of the license. And to the extent that they raise discomforting questions for potential licensors and licenseesand their attorneysthey discourage the adoption of the license.
Fortunately, the GPL preamble has no legal significance and is not going to matter if the license is ever litigated in court. But it is still worth reading and analyzing to understand the license authors' achievements and possible misconceptions.
For example, the first sentence of the next paragraph of the GPL preamble is technically incorrect and the rest of that paragraph is misleading:
If you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights. (GPL Preamble.)
The problem with that first sentence is with the word all in the phrase all the rights that you have. Neither the free software guidelines nor the open source definition require a licensor to grant all his rights; he retains, for example, the right to grant licenses to his own software under different terms than the GPL, and the right to refuse to issue new licenses. Technically, a copyright owner retains all his or her rights and merely grants licenses to others in accordance with certain terms and conditions. The phrase give the recipients all the rights that you have is unnecessarily frightening and is not true.
I think what that first sentence intends to say is that, when you sublicense a GPL-licensed work, you must pass along the software under its original license without adding further restrictions. Only in that context does the rest of that paragraph make sense: You received source code when you received the GPL-licensed work, and so you must provide source code when you sublicense it. And to make sure that your sublicen-sees know that they have the rights to copy, modify and distribute the software and the right to the source code, you must provide them with a copy of the GPL license text, just as you were provided with this copy of the license.
The next paragraphs of the preamble anticipate that the GPL will give licensees "legal permission to copy, distribute, and/or modify the software"; will not provide a warranty; will protect the reputations of the original authors; and will deal effectively with the threat of patents. The actual license terms for this, of course, are not these in the preamble, but those that follow later in the license, under the heading "TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION."