Subject: Re: termless copyright and patents
From: "Ben Tilly" <>
Date: Sat, 7 Oct 2006 23:13:21 -0700

On 10/7/06, <> wrote:
> Ben Tilly writes:
>  > But if you redistribute it, then under item 6 you "may not impose
>  > any further restrictions".  Again it does not say whether you'd be
>  > imposing those restrictions through contract law or patent law, so
>  > you're not allowed to use either to impose those restrictions.
> Your broad interpretation of "extra restriction" would mean that once
> you have released GPL code into the wild, you are no longer allowed to
> use a *copyright* license that is incompatible with the GPL, because
> that would be a restriction on people's ability to combine your non-
> GPL-compatible code with your GPLed code.

Interesting point.  Well, one could use a different copyright license,
but would theoretically (under the broadest possible interpretation)
have to effectively dual license it.  "You can use it under the terms
of this copyright, but you can also merge it into my existing GPLed

I suspect that lawyers have some fancy way of saying, "That's
unreasonable, and therefore that's invalid."  As I've said all along,
it is possible, likely even, that the way that lawyers would say that
would also apply to arguing patents.  However the way that lawyers
would phrase that is beyond my knowledge of the law, and therefore the
likely consequences are as well.

Of course after writing that paragraph above I continued reading, and
I think that Stephen filled me in on what I was missing.  And indeed
it does turn out to be a fancy way of saying, "That's unreasonable,
and therefore that's invalid." :-)

> I say that you are restricted by copyright law from trying to use
> copyright to restrict running the program, by the GPL and the doctrine
> of reliance (which theoretically prevents you from withdrawing your
> license once you've published it) from restricting use of the text of
> the program, and by the GPL's implicit patent license (and in the case
> of GPLv3d2, section 11) from restricting practice of the claims
> embodied in code you convey, or license for release in GPLed code.[1]

Fascinating.  I just googled the doctrine of reliance and came up with,
which has the following checklist for when reliance is invoked:

1. Promisor makes a promise to the promisee

2. Action/Forbearance: Somebody has to rely on the promise

3. Promisor should reasonably expect to induce that action

4. Promise did actually induce the action or forbearance

5. Enforcement is necessary to prevent injustice, and the remedy may
be limited as justice requires

The key here from my point of view is 3.  You should not reasonable
expect me to attempt to modify your GPLed code to make it infringe on
another patent that you have.  Therefore there is no reliance if I do
so, and you cannot be held to your promise to not sue me.  Ditto if I
take your GPLed code and modify it by borrowing from some non-GPLed
code of yours.

However you should reasonably expect me to copy, modify and distribute
your code if you release it under the GPL, so if you sue me for that I
should be able to hold you to your promise. :-)

> Take a deep breath and think about it before you respond.

Breath taken.  Responded.

> Footnotes:
> [1]  All of the statements require a clear chain of title