I think about economic justice...

You have 1000 free men and 1000 slaves producing the goods that allow them to be free. The free men work, to be sure, but they get out what they put in, and they also get out the majority of what the slaves put in. Productivity increases, and we now have 1,000,000 free men and still 1000 slaves. Is the situation better, because as a percentage there are fewer slaves? Is it the same, because there are still 1000 slaves? Is it worse, because with the productivity increases, there's less justification for having 1000 slaves?