I'm just watching Roots, where the white slave drivers routinely rape the black women, and then enslave their half-white kids as well. I was just wondering what they thought of the hybrids. I mean to put it in context, that's like me having a son with a chimpanzee. And then enslaving it. Wouldn't that have some kind of controversy surrounding it?
Were half whites considered half human? Where there taboos around the subject, or intellectual debates between competing theories? What did the church have to say about it? Was it not frowned upon to enslave your own blood?
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I'm not that knowledgable on this specific subject, so you will need someone else to answer in more detail. However, I can provide some insight as to why it's even possible that someone who is clearly human to us, wasn't seen as such for a very long time.
The interaction with native Americans, reinvigorated a long-lasting discussion within christian theology. I'm not sure when this "Roots" takes place, but at the time this discussion was taking place, most Europeans had a worldview which vastly differed from yours. They did not categorize their surroundings according to biological categories, the way you just did. Some animals had a soul, like humans. Most did not and weren't on the same level as humans. We contribute the things which make us human to our brain and our appreciation of living things is inspired by our biological knowledge. In contrast, it was a very popular notion amongst medieval and early modern christian to contribute those same qualities to a divine soul. So if something didn't have a soul, it was almost an object. I guess you could compare it to a robot without AI. Perhaps it was still made by God -or the Devil-, but it wasn't made in his image or infused with it's divinity.
Some argued that either -or both- black people and native Americans were not human and had no soul. Their arguments were that they weren't mentioned as such in the bible, their skin wasn't as pure -tainted- as that of white people and they were 'clearly' barbaric and less civilized. However, in 1537, Pope Paul III attempted to settle this dispute by proclaiming that Native Americans had a soul and that they had rights. However, this wasn't the end of the dispute and it took years before this was popular opinion and before slavery was abolished. Practice doesn't always follow theory though, so the actual history of slavery is more diverse and complicated.