First, I wish to appologize.
     While I am actually fairly familiar with the GPL,

    I am not intimate with either the various forms of BSD License or

the ISC.

    Somehow jumping back and forth between them all on wikipedia before

my original

    post I missed the clause that appears to be in each of them require

preserving the

    License/Permissions as well as the copyright.
    I made an honest effort to  look, and somehow read right through

exactly what I was looking for.

    I went back over the ISC a second time before posting, but I read

what I was expecting to see, not

    exactly what was writing.
    That fairly well obliterates the main point I was attempting to make.
    But many of the other issues are still valid.
    The argument that you start with copyright and then add or subtract

based on the license is

     correct.
    But you can not expect copyright law to return, rights you cede in

your license.
    Yes, a License is a legal document, and MOST legal documents are

immutable,

    but generalization is not the same as law.
    The ISC and BSD Licenses are immutable, because although they cede

alot, they do preserve that.
    They are not immutable, because all legal documents are inherently

immutable.