I'm teaching a module on the Ethics of Public Policy this semester which will cover, inter alia, marriage. Naturally the focus is likely to be on gay marriage, though we'll also discuss other things such as polygamy and arguments for the abolition of marriage. But one of the readings will be this piece by Ralph Wedgwood.
In this article, Wedgwood is concerned with the essential social meaning of marriage - a meaning which, he claims, does not restrict marriage to being between a man and a woman. However, he has to grapple with whether other, decidedly more unusual, cases of marriage might also be possible. In particular, he mentions examples of people marrying their dogs or their cars (p. 233) or one man marrying another man's left foot (p. 239). The problem, for a liberal view of marriage, is whether it can be permissive enough to allow gay marriage (and, perhaps, polygamy) while excluding such cases (assuming that we want to disallow them).
Wedgwood claims that, so far as he knows, no one actually wants to enter into these alternative forms of marriage (p. 239). It seems that this isn't entirely true, as the following example illustrates.
Artist Jodi Rose 'married' the Pont du Diable (Devil's Bridge) in France. Her account, in which she describes her and her bridge as "Officially *symbolically united" can be found here. The story was covered by the Metro and Huffington Post, both of whom make clear that the union is not legally recognised in France.
I think there are questions here as to whether there's any real (i.e. literal) sense in which this can be described as a woman marrying a bridge, as opposed to some fanciful make-believe. Further, before this could be a problem for Wedgwood's case, we'd need to consider whether or not she really wants this marriage to have the significance usually attached to other marriages. Perhaps, for instance, it was more of an excuse for a wedding party or a way to publicise her bridge singing party. Nonetheless, I think it's an interesting case to consider, especially when some people insist that marriage must - by definition - be between a man and a woman.