Aristotle had no problem with slavery – which he saw as the natural order of things.
Some people were simply born with inferior minds – so it made logical sense that they would be the property of more rational men who would tell them what to do.
In sum men ruled women – slaves – animals – land and sea.
A rational mind could see these immutable truths of nature.
And yet why couldn’t Aristotle’s brilliant mind see his own inherent self-interest in proclaiming the perfection of man?
The Dominican monk St. Thomas Aquinas (1225–74) was a great admirer of Aristotle.
In his 3,500-page Summa Theologica he drew heavily on Aristotle’s ideas and laid the foundation of Catholicism for centuries to come.
Because the Greeks had been pagans some revision was necessary.
In Aquinas’s version the Great Chain of Being was revised as Scala Naturae – which was more or less the same except for the addition of a couple of layers at the top: God and the angels at the apex – reigning over man.
God was rational and the author of everything.
He had made man rational – giving him free will to choose sin or obedience to faith.
Aquinas kept the part about men ruling over women – slaves – animals – mammals – fish – earth and sea.
And he explicitly explained that men should not worry about killing or causing suffering to animals because they had no souls and were as dumb as trees.
We wouldn’t feel bad about cutting down trees – would we?