Vicki, I'm guessing that Groobie (and others) agree that there are valid reasons for the first three restrictions on marriage because (the first two, at least, of) these reasons can be grounded in some sort of objective fact, or laws existing elsewhere in society for people's protection.
Minors under a certain age should not be allowed to marry because society generally agrees, supported by educational and developmental psychology, that minors are not mentally and cognately capable of making those kind of decisions. Minors are also not allowed to vote, join the armed forces or make their own decisions on medical treatment, among other things. These restrictions are not applied to same-sex couples or gay people generally.
Siblings and close relatives are not allowed to marry not only because of a societal taboo, but for genetic reasons: we know that 'in-breeding' leads to a greater incidence of birth defects and genetic weaknesses being introduced into families.
As for someone who is already married, that's probably the weakest of the three, in that there aren't scientific, objective or legal reasons for this beyond that 'society believes that it's objectionable'. I don't believe that our society as a whole is ready to consider breaching that taboo at present, if it ever well. I do believe that society is ready, or close to being ready, to agree that same-sex marriage is not the taboo that it used to be.
Finally:
If we change the institution of marriage so that we are promoting the general idea that people should find someone to love and share their life with, then the institution of marriage ends up promoting something wonderful for the individual but of no particular benefit to the society. Marriage, as a societal institution, becomes meaningless. As we are starting to see in countries which have already changed the definition of marriage, when you make marriage meaningless, fewer people bother to get married. And I believe that will have serious consequences on society.
I can't even argue with this, Vicki, as I don't think I even understand the basis on which you're arguing. How does marriage have benefit to society now? How does changing it to allow a contract between two people of the same sex as well as two people of the opposite sex make any difference to whether marriage is of benefit to society or not?
I'm also not remotely convinced that the decline in marriage has anything to do with same-sex marriage. Marriage has been in decline in the Western world for the past thirty or so years. Many couples opt to live together rather than get married - either as a revolt against what they consider to be an outdated tradition, or because they can't be bothered with all the paperwork and/or they don't really think of their relationship as permanent. You'd have to show statistics demonstrating a consistent, ongoing decline in heterosexual marriage
since the legalisation of same-sex marriage in countries such as Norway, Canada and others to support that particular argument.
Wendy
