In the ancient world, slavery was hardly a moral dilemma. It raised no ethical issues worthy of examination, nor was it ever considered a source of embarrassment. That most of mankind could be forcibly enslaved without injustice was a truism that was seldom debated, even among philosophers. Nature had assigned some men the role of master and others the role of slave. This was so obvious it required no elaborate rational explanation; for centuries, the belief that the stronger had a right to dominate the weaker was always regarded as true, but trivially so. The great exception to this universal indifference was Aristotle, the only classical writer to develop a fully-fledged theory of natural slavery.Nobody in the West would defend slavery today.
In Aristotle’s Politics, the “natural slave,” the man who could be enslaved without injustice, differed from the free man in certain fundamental respects. Nature had designed the slave for servile labor; he was brawny, but filled with humility because of the shabbiness of his appearance; in contrast, the free man, because of his “upright posture,” had a commanding presence or an air of dignity about him that made him ill-suited to working with his hands. Instead, Nature had designed him for the civic life of the polis. The slave shared “in reason to the extent of understanding it, but does not have it himself”; compared to the free man, he was deficient in reason. By this, Aristotle did not mean that the slave was necessarily deficient in technical rationality; rather, he lacked the autonomous practical rationality or deliberative choice needed to achieve eudaimonia or happiness.
Natural slavery had an ethnic component. Aristotle divided humanity into three main branches; northern Europeans, who were spirited or full of energy, but “deficient in intelligence and craft knowledge”; Asians, the Persians and other Near Eastern peoples, who were both intelligent and possessed craft knowledge, but lacked spiritedness, and; the Greeks, who possessed both intelligence and spiritedness because of their geographically intermediate position between Northern Europe and Asia; ergo, non-Greeks were barbarians who could be enslaved without injustice. Although the barbarians of Northern Europe were “comparatively free,” this didn’t mean they weren’t natural slaves; true freedom requires the capacity for autonomous practical rationality, which the barbarian clearly lacked.
We have a system today that is better than slavery for the elites. Companies can fire workers for almost any reason. Companies can also cut back hours, and require unusual working conditions. Companies don't have to train workers, or pay their health insurance, or contribute to their retirement.
Slaveowners had to do all of those things.
The trend is toward companies like Uber not employing anyone directly, but making them all independent contractors. Then employers have almost no responsibility for anything.
Most workers get saddled with enormous debt, from student loans, mortgages, and credit cards. They are enslaved by debt. But we have figured out a way to say that it is all voluntary, so it is all okay.