The following comes from a Sept. 10 posting by Michael Cook on Conjugality, a blog on Mercator.net.

Last week the US Seventh Circuit Court of Appeals unanimously upheld a district-court ruling that had struck down same-sex marriage bans in Indiana and Wisconsin. Judge Richard Posner wrote the decision, a brilliant piece of rhetoric which was studded with sparkling one-liners and dripping with sarcasm. “Hero Federal Appeals Judge Burns Down the Case Against Gay Marriage” was the headline in Gawker, a widely-read website. “A masterpiece of wit and logic,” was the verdict of Slate’s columnist.

Since the 75-year-old Posner is the most-cited legal scholar of the 20th Century and one of America’s leading public intellectuals, his views are bound to be influential as same-sex marriage heads for the Supreme Court.

But stripped of their sequinned garments Posner’s views are not as muscle-bound as they first appear.

His strength is identifying absurd inconsistencies in arguments and using them to pry open the door for new interpretations. For instance, he points out that Indiana bans marriages of first cousins until they are well past the age of procreation at 65. “Elderly first cousins are permitted to marry because they can’t produce children; homosexuals are forbidden to marry because they can’t produce children,” he writes.

Gotcha!

There are many entertaining Gotcha moments in his decision, too many, in fact, for they distract readers from his weakness on the fundamentals. His case rests on three legs, all heavily reliant on social science scholarship.

First, he argues that homosexual orientation is genetic, an immutable and innate characteristic rather than a choice. To support this he cites a 2008 brochure from the American Psychological Association – not exactly the summit of genetic scholarship, although admittedly, it is the APA’s official view. However, no genetic cause has yet been identified; homosexuality’s origin is still an open question.

Besides, if homosexuality is genetic, it should have disappeared according to evolutionary theory, as homosexuals do not produce offspring. Posner acknowledges that this is a problem, but says that the “kin selection hypothesis” shows that homosexuality is compatible with evolutionary theory. What he doesn’t say is that the kin selection hypothesis is so controversial that it has been criticized by the Harvard evolutionary biologist who popularized it in the first place, Edward O. Wilson. Whether this is true or false is a matter for the scientists to work out. But the genetic origin of homosexuality is unsettled and contestable. It is hardly a firm plank on which to base a revolution in US marriage law.

Second, he argues that same-sex marriage does no harm to the institution of marriage or to society at large. This is a claim which is impossible to prove in less than two generations. The precedents are not promising. The last revolution in marriage, no fault divorce, was described as a blessing in the 1960s. But after a half-century experiment, it has led to huge changes in family structure, legions of single mothers, violence against spouses, child welfare, a declining marriage rate and so on.

Posner seems quite impressed by a recent study which analysed whether marriage rates fell after Massachusetts permitted same-sex marriage. “Allowing same-sex  marriage has no  effect on the heterosexual marriage rate,” he concludes. So what? An snapshot of Massachusetts marriages from 2004 to 2010 says almost nothing about damage to the institution.

Third, Posner says that the welfare of children should be front and center of arguments about marriage. Since marriage is the best place to raise children, he argues, it is discriminatory to deny homosexual couples the right to raise their children within the framework of marriage.

But he only considers the material benefits of a hefty household income. The real question is whether a marriage with a mother and a father is the best place to raise children. Posner ignores almost completely the psychological effects on children of growing up in a heterosexual marriage, focused as he is on the rights of adults.

How could such a brilliant scholar offer such conventional arguments about social morality based on such weak evidence? The answer is that Posner does not believe in morality….

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