Copyleft VS Permissive Licenses

I have always been a proponent of the free exchange of ideas and information, supporting organizations like Creative Commons and the Open Source Initiative whenever possible. However, what most people don't know is that there are two distinct types of free content on the internet. The distinction between these two types is a crucial and ongoing argument over what it means exactly for content to be 'free'.

All content on the internet, even free content, is subject to copyright. Free content works by granting you a non-exclusive license to use that content in ways that are normally reserved for the copyright holder, such as the ability to modify and redistribute the work. However with all the different types of licenses available, the subtle differences between them can be more than a bit confusing.

At this point, I would like to state that I am not a lawyer. Like most people, reading legal text makes my head spin. So you should not take any of this as legal advice. Furthermore, the ideas expressed in this article are my personal opinions only. If you disagree with me that is fine. You should use whatever license is most appropriate for your work. That said I hope you will find my insights useful.

Basically there are two different types of free licenses: permissive licenses and so called “Copyleft” or “Share-Alike” licenses. Permissive licenses allow you to copy, modify, recombine, and redistribute the work with minimal restrictions. Usually, only attribution is required. Copyleft provides the same permission as a permissive license, but requires you to release any derivative works you make under the same copyleft license.

PERMISSIVE LICENSES:

• MIT License
• BSD 3-Clause
• Apache License 2.0
• CC-BY 4.0

COPYLEFT LICENSES:

• GNU GPL v3
• GNU LGPL v3
• Mozilla Public License
• CC-BY-SA 4.0

The core idea behind copyleft licenses is that if you use free content, anything you make with that work should be free as well. For example, if you release a project under a copyleft license, and someone else takes that project and makes improvements to it, then you can incorporate those changes back into the original project without their permission. It also prevents companies from profiting from open source content, without giving back to the open source community.

The proponents of copyleft licenses argue that free content should always be free, even if it is changed by someone else later down the line. While I agree that this is a noble and worthwhile sentiment, in practice things become much more complicated. Using a restrictive, copyleft license can create unintended (often severe) consequences that make the work less-free than it otherwise might have been.

For instance: If you were to release a software library under a copyleft license like the GPL, and someone else wanted to write a program that used both your library and a proprietary library (maybe they need it to read PDFs or play MP3s), they would not be allowed to do so. The GPL required that their entire program, including any libraries, also be released under the GPL, something that the proprietary library strictly forbids.

Another example: suppose you release your stock photography under an CC-BY-SA license, and someone else wanted to use your stock photography to build a website. Would it then be necessary for their entire website to be released under CC-BY-SA as well? Unfortunately it's not entirely clear, and some people may wish to avoid using your photography even if their use of it would be entirely legitimate.

I am personally of the believe that all creative work is derivative. Everything we make is inevitably inspired by the work that came before it. Like biological creatures, ideas must be able to copy, mutate, and recombine in order to successfully evolve. Only by taking inspiration from several different sources are new ideas able to spring fourth.

Copyleft licenses allow a work to be copied and mutated, but it falls short of allowing works to be recombined. Copyleft effectively erects a wall between free and proprietary content, never allowing the two to be used together. Material that uses a permissive license can always be used in a copyleft work, but the reverse is not true.

Permissive licenses also have the advantage of being short and easier to understand. The MIT license is only 158 words long, while the GNU Public License v3 contains a whopping 5,495 words. And what's the one thing that no-one ever does when installing new software? Read the license!

Proponents of copyleft often say that the using a permissive license is like giving proprietary companies a free hand-out. Companies can take advantage of permissive content without contributing anything back to the open source community. However even if they use permissive content, they still must attribute the creators of that content, making it easy to expose them for what they are.

I personally think it's better to teach by example, rather than force others to follow my ideology, as copyleft seems to do. Using copyleft would also mean restricting certain uses of my work that I would otherwise want to support. For this reason, and others, I choose to use permissive licenses wherever I am able.

Note that I do not have anything against people who prefer copyleft license. In fact, I hope they find my work useful and incorporate it into their own. I can see why it is appealing. But for me, personally, permissive licenses are the best way to go. If you have read this far, I hope that you will give them some consideration.

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Cover Photo by: Brian Turner