Compatibility of the AFL with the GPL

[Richard Stallman]

    The trademark clause in the AFL merely states that "Neither the names of
    Licensor, nor the names of any contributors to the Original Work, nor
    any of their trademarks or service marks, may be used to endorse or
    promote products derived from this Original Work without express prior
    written permission of the Licensor."

This goes beyond the requirements of trademark law, which permits
some kinds of use of the trademark as fair use.

    Why can't a licensor prohibit the use of his trademarks or his good name
    even while he provides a TOTALLY FREE copyright license to his software?

You are arguing against a statement I did not make.  I never said that
a free software license cannot include such a requirement.  On the
contrary, we recognize the AFL as a free software license, trademark
requirement and all.  The question here is compatibility with the GPL.

The trademark requirement of the AFL is nontrivial because it goes
beyond what trademark law requires.  Therefore it is a restriction
that is not in the GPL, and that makes the licenses incompatible.

As it happens, I disapprove somewhat of this trademark requirement--I
think it goes too far.  But that disapproval is not condemnation.
We recognize the AFL as a valid free software license.

    I'll leave for another thread any discussion about whether this is a
    good idea or a bad idea.  But how is it incompatible with the GPL?

It is a requirement that isn't in the GPL.  The GPL, being a strong
copyleft, does not permit adding requirements of any sort.  So any license
that has requirements not in the GPL is incompatible with the GPL.

    ***Anyone*** is free to take software licensed under the AFL and
    re-license it under any license, including licenses not containing the
    Mutual Defense provision ["to use, copy, modify, merge, publish,
    perform, distribute and/or sell copies of the Original Work and
    derivative works thereof,..."].

If I relicense in this way under a license such as the X11 license,
which includes neither the mutual defense nor the trademark provision,
does that make those provisions completely cease to apply to the code
as I redistribute it?  Or does it only mean that they come from the
author and not from me?

I assumed it was the latter, and my conclusions are based on that.

If it is the former, then the AFL is indeed compatible with the GPL,
but the mutual defense and trademark provisions are completely
ineffective because they are so easy to weasel out of.  Surely that is
not what you intend; you must surely intend these provisions to bind
all users of the code.  That is why I expect it is the latter--that I
could put on a license from me which doesn't impose such requirements
from me, but that would not negate the requirements imposed by the
first author.


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