This is a linkpost for https://atheistkit.wordpress.com/ethics/
Do you think the idea is sufficiently coherent and non-self-contradictory that the way to find out if it's right or wrong is to look for evidence?
You do understand that debates about objective vs relative morality has been going on for millenia?
They might also need to figure out that people are equal, too
No, they don't if they themselves are in danger of becoming slaves. Notably, a major source of slaves in the Ancient world was defeated armies. Slaves weren't clearly different people (like the blacks were in America), anyone could become a slave if his luck turned out to be really bad.
Right. Someone could be against slavery for THEM personally without being against slavery in general if they didn't realize that what was wrong for them was also wrong for others. That's all I'm getting at, there.
Or do you mean that they should have opposed slavery for everybody as a sort of game theory move to reduce their chance of ever becoming a slave?
"You do understand that debates about objective vs relative morality has been going on for millenia?"
What I'm getting at here is that most moral theories are so bad you don't even need to talk ...