Frank Hecker wrote:
> A more interesting question is, are any of those GPL-compatible licenses
> copyleft licenses? I have never seen this stated explicitly, but I
Most people have a one-dimensional concept about licenses. They only
rate license according to their openness. However, there is an equally
important dimension, namely cooperation. See for example
http://devlinux.org/devLicense.html
The problem with GPL is that its strongly defensive posture makes it
a very uncooperative license. Interestingly, its tactics backfires as
your question indicates. In an attempt to guard copyleft by all means
possible, it "kills" (i.e. refuses to cooperate with) any similar
attempts. This forces any compatible license to have a much weaker
notion of copyleft.
As an example, we have been using MPL for another project, and have
naturally received requests, similar to those that the Mozilla
community have received, about re-distributing the project under a
GPL-compatible license. The disjunctive MPL/GPL dual-license was
considered and rejected because it would allow the project to become
GPL-only, which is would be unacceptable to us (the project is used
in several commercial applications). Instead we opted for a MPL/BSD
dual-license. This weakens the copyleft of the project, which is the
the opposite effect of what the FSF wants to achieve -- and the irony
of it all is, that GPL was the direct cause of this shift.
> suspect that the only copyleft licenses that the FSF would ever consider
> compatible with the GPL are the GPL itself, LGPL, dual licenses
> involving the GPL or LGPL, and minor variants of the preceding licenses.
I tend to agree. The underlying mechanism seems to be that a license
will only be GPL-compatible if it (1) does not prevent the terms of
GPL to apply, or (2) it can be transformed into GPL.
Many people who uses the LGPL, seems to be woefully unaware about
section 3, which allows anybody, at any time, in any kind of weather,
to transform LGPL into GPL. As somebody once said, the road to GPL is
a one-way street.
> There have been at least two attempts to create non-GPL copyleft
> licenses "from scratch", the NPL/MPL and the Jabber Open Source License,
> and the FSF considers both of them incompatible with the GPL.
GPL does not promote copyleft, only "GPL copyleft".
