Dick couldn't understand how his argument in favour of gay marriage was weakened by disputing John's argument that the institution of marriage has been negatively affected by recent developments. Perhaps after reading John's latest thoughts he might have a better idea why. There are two separate arguments which John conflates.
1. That [heterosexual] marriage is beneficial and has been weakened, passively and actively, by various disincentives to marry.
2. That homosexual marriage changes our view of marriage as a "special bond between a man and a woman", opens up the possibility of incestuous and bigamist "marriages" and this will have a detrimental effect.
The thing is, argument 1. is reasonable and defensible. Dick is perfectly entitled to disagree but their disagreement is founded on differing philosophical views about society and not on simple matters of logic. There isn't a resolution to this argument short of Dick's conversion to conservatism or John's to liberalism. But there is no need to be a liberal to favour gay marriage. This is why I say Dick weakens his argument by allowing it to get sidetracked into this area.
On argument 2. This remains a "touchy-feely" argument with little solid logic. We think of marriage as a special bond between a man and a woman. Should gay marriage become legal, some of us would think of marriage as a special bond between two people, which most of the time would mean a man and a woman. So what? The prior argument revolves around specific disincentives to marriage which demonstrably reduce the rate of marriage. There is no explanation of the supposed corrollary from gay marriages to polygamous or incestuous marriages. This argument relies on the notion that we will "feel" differently about marriage. But there is no demonstration how "feeling differently" translates into deciding not to get married. In fact, if anything, there is an equally valid argument that greater levels of marriage among homosexuals will encourage their feckless straight friends to tie the knot!
John says he is not, as I suggested, "post-rationalising a gut feeling" but I would be wary of holding to a position that takes, as he admits, 30,000 words to justify.
I find it hard to shirk the impression that John from Irish Eagle is trying to post-rationalise a gut feeling in his recent posts about Gay Marriage. He has admitted as much when he says:
I'm planning to use the blog as a means to work out my thinking more clearly
Sometimes gut feelings are right, sometimes they are plain wrong but sometimes they "feel right" but are still wrong. I would suggest to John that, for him, this one feels right but it falls apart on closer examination.
John's principal argument is that marriage as an institution is crucial for the continuity of the type of liberal, civil society we currently enjoy and that this has been weakened by recent developments:
Unmarried cohabitation, divorce, "sexual self-fulfilment", children by artificial insemination, etc. have all served to weaken marriage
In fact, Dick, does his counter-argument a disservice by disputing this. Dick is perfectly entitled to argue that this doesn't matter but it is undeniably the case that marriage has been affected negatively by those developments. The thing is, it is easy to explain how these affect marriage as an institution.
1. Widespread acceptability of cohabitation acts as a disincentive to those pondering marriage. If it is possible to obtain the short term benefits of a marriage without the longer term commitment it is easy to how this can make the difference in marginal cases to tip the balance away from marriage.
2. Ease of divorce means that those who enter into a marriage need not necessarily consider that marriage as a life-long commitment.
3. "Sexual self-fulfilment" can contribute to self-centred narcissicism. Greater availability of sexual partners combined with reduced social disapproval of promiscuity is an incentive to adultery for those who are married or an incentive to postpone marriage for singles.
4. Greater availability of artificial insemination, particularly to single women, removes at least one incentive to marriage for women.
The thing is, as Backseat Jon notes, there is no corresponding mechanism which demonstrates how gay marriages affect (heterosexual) marriage. The only way it is possible to make that argument is to hold that greater visibility and acceptability of gay marriages acts as some sort of incentive for the hitherto heterosexual to experiment in homosexuality. This seems to me an extremely tenuous notion and, to be fair to John, he has resisted employing this line so far. The problem is, he isn't left with much else.
It is a good idea to re-examine your starting position if you find that its logic takes you into unexpected areas. John has found himself arguing that a marriage is somehow a contract with society: "With this ring I do promise to uphold my obligations to society" doesn't have much of a ring to it, does it? In support of his notion that childless homosexuals undermine marriage he states that:
If a [heterosexual] couple gets married with zero intention of having children, then that does undermine marriage. Not the same for infertile couple because they obviously respect what marriage is about.
But surely if they really respected what marriage is about - a contract with society to attempt to produce children according to John - they would refrain from getting married?