But moderns don’t even agree on morals with each other,
I reckon the vast majority of modern Westerners believe that certain rights extend, without exception, to all individuals at least in principle and are inalienable; that sex should be consensual and never coerced; that entire groups of people do not deserve to be treated as sub-humans and subjected on occasion to slaughter for the education of young warriors (as in Sparta); that disabled people deserve dignity and should not be subjected to discrimination or left to die at birth (as per the Roman constitution) and that fathers do not possess life or death over their children etc. etc.
There are certain norms that mark all liberal representative democracies derived from the enlightenment and these norms are not in anyway traceable from classical Greece or Rome.
I’m not denying the philosophical, mathematical, architectural, literary, legalistic and political influence of the fertile classical civilizations.
But to attribute our morality to them is very short-sighted.
It also neglects the genius of other cultures. Meritocracy, for example, was in origin a Chinese, Confucian philosophical concept.
The ancient Sumerians and Egyptians wrote treatises on ethics. The ancient Indian civilization had Vedic philosophers as every bit profound in their analyses as our own Greeks and Romans - you had for instance the Charvaka, an astika school that taught materialism, like our Greek atomists or Epicureans, as well as empiricism and philosophical scepticism.
And they had Jain philosophers who were even more uncompromising in their commitment to non-violence (
ahimsa) than any science of ethics pioneered by Westerners.
You are overlooking much that Christianity and enlightenment philosophy had to “
disabuse” itself of in classical moral systems, while looking purely at the compatible elements.
As a whole, the Graeco-Roman worldview is alien to our own morally speaking.
Christianity is a universal faith, not bound to any particular philosophy or culture, as Pope St. John Paul II once said in
Fides et Ratio.
"
The Church has no philosophy of her own nor does she canonize any one particular philosophy in preference to others.
My thoughts turn immediately to the lands of the East, so rich in religious and philosophical traditions of great antiquity.
Among these lands, India has a special place…the context for great metaphysical systems. In India particularly, it is the duty of Christians now to draw from this rich heritage the elements compatible with their faith, in order to enrich Christian thought… .” -(
Pope St. John Paul II. "Fides et ratio, 49 )