Responding now to myself using my actual views, just so I don't accidentally persuade anyone to approve of slavery.
When figuring out what people really want, it's better to look at what they do than what they say. We of course all walk around with the notion that we are against slavery and that it's a horrible evil and all that, but there is more slavery in the world right now than at any point in history. Without consulting the internet, can anyone name an organization dedicated to eradicating slavery? A high-profile spokesperson for the anti-slavery cause? Most of you can't, because you've decided slavery's not really that big a deal. Below, I will argue why you are correct to evaluate it that way.
There are lots of terrible, atrocious, or scary things we don't think about or aren't focused on; it doesn't mean we approve of them or even that we don't think they're important.
Our foundational texts provide broad sets of values, attitudes, and a basic but incomplete picture of our identity. They do not prescribe in detail how we are to live and who exactly we are to become. The Bible is on the whole uncritical of slavery, but it does not explicitly condone it either, and parts of the Bible specifically describe the rights of slaves which suggests that much of the behavior we associate with slaveholding is indeed immoral and should not be tolerated.
Anti-slavery voices among us have not merely been tolerated, but have managed to overturn slavery as an acceptable institution. This is extremely important; nowhere else has an anti-slavery movement had this kind of success. The fact that it happened for us is no less an important indicator of our values and way of life!
Some great advances within our society did happen to coincide with expansions in slavery, but many others did not. See for example all the advances of the 20th century.
This paragraph is basically true, but it does not support the argument that slavery is OK.
Just because the media are generally untrustworthy does not mean they are wrong 100% of the time. We know the horrors of slavery, and they flow logically from slavery's inherent power imbalances and from what we know about how humans respond to power. On paper it is theoretically possible that slaveholders don't necessarily have an incentive to mistreat their slaves, and there are no doubt examples of a few who didn't, but any sane reading of both history and world events quickly rebuts that pattern. Slaves are readily bought and sold, and are regularly abused. We have both historical slave narratives and contemporary testimony to support that.
Yes, human psychology can produce strange results. It does not mean those results are moral.
Those measures may be quantifiable but they are not meaningful to an understanding of slavery's morality. Whatever positive conditions could be pointed to among enslaved populations, better conditions existed for them after they were freed, given their participation in functional free culture. The American black legitimacy rate, for example, was higher than that of whites up through the early 20th century, while their rate of criminality stayed roughly equal to that of whites for a long time after slavery as well. It was other factors--not being given freedom!--that contributed to what we now would call the "decline" of black America.
This is downright foolishness. We must not sacrifice our moral standing for the Good Of The Economy, even if the financial logic above was sound. Which it isn't: if a stock market can't be based around slaves, people will find other commodities to speculate on. If people can't borrow against their slaves, they will find some other measurable assets against which to seek credit. Note that the United States continued to be the major world financial power long after it abolished slavery, and that even before it abolished slavery it was the slavery-free north that actually fared better economically.
Moral relativism is stupid, and only results in the tolerance of immorality which is tantamount to immorality itself. Yes,
it's good to be epistemologically humble (thus this whole series of threads!) but that should be used to strengthen rather than paralyze one's basic sense of right and wrong.