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cc-licenses - Re: [gnu.org #238740] Derivatives of dual-licensed Creative Commons Attribution-ShareAlike and GFDL works

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  • From: Evan Prodromou <evan AT wikitravel.org>
  • To: licensing AT fsf.org
  • Cc: cc-licenses AT lists.ibiblio.org
  • Subject: Re: [gnu.org #238740] Derivatives of dual-licensed Creative Commons Attribution-ShareAlike and GFDL works
  • Date: Wed, 04 May 2005 21:42:46 -0400

On Wed, 2005-05-04 at 18:16 -0400, Dave Turner via RT wrote:

> > 1) Does "precisely this License" in the GFDL mean "only this license,
> > to the exclusion of all others"?
>
> This question is so imprecisely stated that I don't want to answer it
> as-written for fear of ending up being misunderstood later

Really? I thought it was a pretty straightforward question. Are you sure
you can't make some sort of effort to answer? Could you rephrase the
question to be more clear, and then answer that question?

> Instead, I'll answer the implicit question, which is whether your
> analysis of the GFDL's copyleft clause is correct. It is not.

Like most people, I'll be much more convinced if, in telling me that I'm
wrong, you also tell me how and why.

> Someone who distributes a dual-licensed derivative of a dual-licensed
> work *is* distributing precisely under each license; they're just also
> permitting other uses.

See, that's the problem with the word "precisely": it's not precise
enough. B-) "Precisely" could mean "_at_least_ this license in its
entirety" or "this license in its entirety _and_no_other_".

It more often means the latter, in plain English. "Precisely ten litres
of water" usually doesn't mean "ten litres, and also two or twenty or
2000 additional litres of water", but "_exactly_ ten and no other
amount".

Anyways, making a derivative work available under an identical license
isn't a _permission_ granted by a copyleft license; it's a _requirement_
that licensees have to meet in order to exercise other permissions. The
question, in dual licensing derivative works, isn't whether permission
is granted, but whether requirements are met.

Consider, if you will, these three cases.

------

Case 1:

Alice makes a work and offers it to recipients either under the terms of
License X or License Y at their option.

License X: "You may make and distribute derivative works if they are at
least made available under License X."
License Y: "You may make and distribute derivative works if they are at
least made available under License Y."

Bob makes a derivative work and he also offers it to the world under the
terms of either License X or License Y. That's OK: he's complying with
the terms of either license -- it's moot which option he actually chose.

------

Case 2:

Charlie makes a work and offers it to recipients under the terms of
License U or, at their option, License V.

License U: "You may make and distribute derivative works if they are
made available under License U and no other."
License V: "You may make and distribute derivative works if they are
made available under License V and no other."

Diane makes a derivative work. Can she make it available to recipients
under the terms of License U or, at the recipients' option, License V?
That doesn't conform to the terms of License U, nor to the terms of
License V.

If she doesn't get the right to do it from License U, nor from License
V, where does she get this right? Barring a separate exception from
Charlie, she's forced to make the assumption that she has an implicit
license, based on his dual-licensing the work. That's not a comfortable
position to put her in.

------

Case 3:

Evan makes a work and offers it to recipients under the terms of License
U or, at their option, License Y (as above).

Francine makes a derivative work and offers it under the terms of either
License U or License Y. She can do so because License Y says it's OK.
License U says it's not OK, but that's immaterial: she can exercise the
rights granted in License Y, regardless of what U says.

-------

I don't think the ShareAlike element is anything except like License U
(although I'd be happy to hear otherwise from someone at Creative
Commons -- hint hint). The GFDL is harder -- "precisely" being such a
poor choice of words.

I'm going to take your response to mean either that a) the GFDL is like
License X, so a GFDL/Attribution-ShareAlike dual license is more like
case 3 than case 2, or b) my understanding of case 2 above is somehow
flawed.

I'd love clarification, but I guess I can live without it. Thanks for
taking the time to respond.

~Evan

P.S. Lest you think that this is an angels-on-pinheads issues, I assure
you it's not. Wikitravel travel guides are available under the Creative
Commons Attribution-ShareAlike 1.0; Wikipedia articles are available
under the GFDL. Some editors of both systems look pretty expectantly to
dual-licensing, but questions about derivative works abound. As you
probably know, wikis are great big derivative-works machines.

--
Evan Prodromou <evan AT wikitravel.org>

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