In my third and final installment about polygamy (my polygamy trilogy), I want to challenge the usual answers people give when asked to make sense of polygamy.
1. It was part of the "restitution of all things." In other words, it was part of the restoration of the gospel. However, polygamy, as practiced in the Old Testament, was never a religious commandment, nor was salvation ever affixed to the practice of polygamy. It was simply a social practice of Middle Eastern cultures at the time - limited in scope to rich and powerful men who could afford to care for multiple women and their children. Levirate marriage, as outlined in Deuteronomy 25:5-10, was to allow men to care for their deceased brothers wife and children. Brigham Young and Heber C. Kimball did marry some of Joseph's wives after his death, but Joseph had married them first while they were either young single women, or else young women married to another man. Joseph never married the widows of his brothers.
2. The most cited explanation for polygamy is found in the Book of Mormon (Jacob 2:30) where God says "For if I will, saith the Lord of Hosts, raise up seed unto me, I will command my people. . ." So, the justification is to have more righteous people. However, according to a new study just published, Mormon polygamy actually decreased the number of children born to women, rather than increased it. This is consistent with studies of other polygamous societies; polygamous females have less offspring than monogamous females. It's only the male polygamist who increases their genetic offspring (or evolutionary fitness) in polygamous societies.
Faced with such facts, LDS apologists are sometimes quick to explain that the Book of Mormon verse refers not to the quantity of seed, but rather the quality of it. Polygamist children, it is claimed, were somehow more faithful or righteous than their monogamist cohort. First of all, there is no evidence to this claim. Second, to me, this sounds like eugenics. Eugenics was a movement started in the late 19th century by Herbert Spencer and Francis Galton, (sometimes called social Darwinism) based on the misunderstanding of Darwin's theory of natural selection. None of the eugenics movements turned out well for the master races involved; and its implementation usually led to nationalism, racism, imperialism, or fascism.
3. Another popular justification is that polygamy was instituted to take care of all the Mormon widows and immigrants in Utah, who couldn't find a husband otherwise. This explanation, however, doesn't explain why Joseph Smith started the practice of polygamy in the 1830's long before the saints migrated to Utah. It also doesn't explain why he married so many young girls, single women, or women who were already married. Also, if you examine Utah population demographics from 1850-1900, it was actually the men who consistently outnumbered the women. Mormon polygamists were not marrying financially bereft widows; they were marrying young girls. The average age of a second wife was 17, and the average age of the third wife was 19.
UFO cults. However, it should be obvious that this is a strange phenomenon of human psychology; not evidence that the sacrifice was justified.
This phenomenon has been shown in study after study. One of the first observations of this phenomenon was published by social psychologist Leon Festinger in his classic book "When Prophecy Fails." Festinger had infiltrated a UFO cult that believed the world would be destroyed by a flood before dawn on December 21, 1954. They also believed their group would be rescued at midnight by an alien spaceship from the planet Clarion. How did they know this? Because their leader, a suburban housewife named Dorothy Martin, claimed to have received instruction from aliens on planet Clarion, and had written them down via "automatic writing."
So, on the appointed night of world-wide destruction, most of the cult met at Martin's home and waited for the aliens to rescue them at midnight. When the alien did not arrive at the appointed minute, they sat in stunned silence and began to feel nervous. By 2 A.M. they began to panic. But at 4:45 A.M., Mrs. Martin (conveniently) received a new revelation: The world had been spared because of the group's faith, and they were to go and tell others about the amazing miracle that had just occurred! (Interestingly, Dorothy Martin's husband was skeptical of his wife's prophecies, went to bed early, and reportedly slept well.)
Festinger predicted that UFO cult members who had sacrificed the most for the cult (some had given away all their possessions, quit their jobs, and left their families) would increase their belief in the cult, and would try even harder to convert others. This is exactly what happend. Those members who were with Martin went out and redoubled their efforts to convert others, and felt even more convinced than before of the truthfulness of their prophetesses abilities. However, Festinger also predicted that the cult members who sacrificed little for the cult (those who had stayed home on the evening of December 20th, and hoped the world wouldn't end as prophesied), would quietly lose their faith. And the majority of them did - quietly distancing themselves from the UFO cult since Martin's prophecy obviously failed.
Those who sacrificed the most needed to justify the great sacrifices they had made. Those who sacrificed very little didn't have as much sunken costs into the group, didn't feel as duped, and therefore they didn't need to rationalize the cult's beliefs as much. This is why successful groups (whether religions or cults or fraternities) ask their members to make large sacrifices to join, or remain in good standing. And Mormons are asked to make a lot of sacrifices: giving up coffee, tea, smoking, or alcohol, serving volunteer church missions, giving at least 10% of their income to the Church, taking busy Church callings (more like part-time jobs), wearing special temple garments, and sacrificing their individuality and conforming to what the group expects of them.
The claim that polygamy increased the faith of its followers, is undoubtedly true. But it's also true that giving away your possessions in order to join a UFO cult increases your faith in UFO cults. This, however, doesn't justify a mistaken belief in alien spaceships and UFO cult prophecy. Similarly, even if practicing polygamy increased the faith of early Church members, this doesn't mean that Joseph's revelation on polygamy was valid.