Can you alter the MIT license?

[Jules Bean]

On Mon, 15 Nov 1999, Scott Johnston wrote:

> 
> >Wrong. The MIT (X) license does not give you the right to change the license.
> 
> I'm not sure this is true.  It says at least one copy of the permission
> notice must be included in the documentation, but it not clear whether the
> terms of the permission notice have to remain in force.  There are strong
> advocates for either interpretation, and nothing concrete will be known
> until it is tested in court.  But I've been trying to figure out what people
> think before it gets that far, by studying their actions.

No, no, no.

You can only license something you own the copyright on.  If you give me
some X code, and you've slapped your own license on it, but it's clear to
me that the copyright on the code belongs to MIT [and, indeed, MIT's
copyright essentially ensures that you do make this clear] then I can
totally ignore your license.  You don't own the code, your license is
totally unenforceable.

> 
> - The Free Software Foundation skirted the issue with its repackaging of the
> X rendering capability into libxmi.  They licensed the new library under
> GPL, but the original source files borrowed from X remain under MIT terms
> (even though those files have most likely been modified to embed them in a
> GPL library).

It's the modification that's the key.  The FSF own the modifications, and
the copyright on those is GPL.  MIT own the pre-modified code.  To the
extent that the latter can be separated from the former, it can be
distributed under MIT terms.  To the extent that they're inseparable, both
licenses must be satisfied - possible, since they aren't contradictory.

> 
> - Some will say the Open Group proved you can change the license when they
> (temporarily) modified the terms for X11R6.4.  But they are a special case,
> in that they are the copyright holder for X, and the one party with that
> freedom.

That's exactly the point.  It is *only* the copyright-holder that can
change the license on something.  And even they can't do it
retrospectively on already released code - unless that was licensed under
a 'time-bomb' license with a termination clause, which is common with
commercial software, but wasn't, for example, the case with X.

> 
> - Apple's relicensing of BSD-licensed software under their own open source
> license might be the most fruitful case to investigate.  No one disagrees
> that the sources they started with could still be available under the
> original terms.  But does Apple grant what the FSF granted with libxmi, i.e.
> the right to use original yet modified source files under the original
> terms?

Again, to the extent that I can point at a block of code and say 'this
belongs to UCB', I can wrench it out of apple's code and use it under the
BSD license, ignoring the APSL.  To the extent that it's all muddled
together, and includes something 'substantial' belonging to Apple, I need
to obey both licenses if I wish to copy it.

As an aside, note that the word 'substantial' has force.  Copyright law
ignores 'insignificant' contributions.  The meaning of this will be
determined by common sense - or rather, by the judge in question.

Jules

[Not a lawyer. That wasn't legal advice]

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