However, he goes on to write…
The best summary I've found of the reasons against legalization comes from a Canadian court case.
In 2010, the Supreme Court of British Columbia was asked to reconsider a ban on plural marriage. The core issue was whether polygamy was bad for society. That is, whether anyone besides the partners to a polygamous marriage were harmed by it.
He notes the submissions of Joseph Henrich, which I addressed here, here, here, here, and here. Sunstone notes that Henrich only dealt with polygyny. Quoting from Henrich…
Polygynous men invest less in their offspring both because they have more offspring and because they continue to invest in seeking additional wives. This implies that, on average, children in a more polygynous society will receive less parental investment.
Let’s assume for the sake of the argument that most polygynous men will continue to seek additional wives.
1) How many polygynous men will there be in the first place? Over and over again, I see heterosexual men saying they don’t want to be married in the first place, or that one wife is (more than) enough for them. Being kind and fair in legalizing the polygamous freedom to marry is not imposing polygyny on people who don't want it.
2) What is going on now? In other words, to whom are we comparing these polygynous men? Henrich is apparently comparing these polygynous husbands to men legally married in supposedly monogamous marriages, with no claim to a polygynous or plural marriage. But what about the men who marry and divorce repeatedly, or never legally marry at all, but still have children with multiple women? That’s all legal. It is also legal for men to have ongoing sexual relationships concurrently with multiple women and have children by them all, whether or not they live under the same roof. What the Canadian law does, as determined by the court decision, is say those men and women can’t freely choose to be legally married, or even undergo one or more ceremonies and refer to themselves as married. In other words, the law and court decision do not prevent men from chasing additional women and impregnating all said women even if he has no more time or money to spend on children, but it does prevent men from making a public vow to have a social and financial obligation to those women and children. What sense does that make???
Futhermore, it is legal for women to raise children without any involvement from a father, either as single parents, or in a same-gender relationship (monogamous or otherwise.) It happens all of the time.
And again, polygyny, especially fundamentalist Mormon or Muslim-style polygyny is just one of many forms of polygamy. It is ridiculous to say that three men should not be free to marry because some other man may make more children than he can parent, especially since some men are already doing that without violating any laws.
Also from Henrich…
Greater degrees of polygynous marriage may reduce national wealth (GDP) per capita both because of the manner in which male efforts are shifted to obtaining more wives and because of the increase in female fertility.
May. May reduce. How do we know that? Are we comparing the GDP of Canada to the GDP of an underdeveloped or war-torn African nation, and saying that the African nation’s GDP is lower because of polygyny? Or are we saying that we should discourage people from being so wrapped up in family so they can work more instead?
Yet -- if Henrich is right -- the consequences of legalizing polygyny seem to me dire enough to warrant the ban of it.
Henrich would only be right if we were to become a third-world country giving up modern legal, sociological, and technological advancements, regressing to centuries past. Polygamy in isolated, patriarchal homogeneous, rural/frontier villages is not what we’re talking about. We’re talking about freedom for consenting adults under a system of gender equality.
People are going to use their rights to do some things other people don’t like. That’s no reason to deny such a fundamental right as marriage.
An adult, regardless of gender, should be free not to marry, and free to divorce. And, an adult, regardless of gender, should be free to share love, sex, residence, and marriage with any consenting adults.