It was maintained, not by threats from outside, but by a kind of censor planted inside the mind, who kept it separated into strictly non-communicating compartments. But gradually, the phrase came to mean something different. Astronomy, after Aristotle, becomes an abstract sky-geometry, divorced from physical reality. Its principal task is to explain away the scandal of non-circular motions in the sky. So, events must be denied, and reality must be denied too.
Reality is an illusion.
It is an approximate concept. Or perhaps it is only a creation of Mind. Because all must be circular. I would never dare go public with such a criticism as above, if I could not offer something from myself. Something that can be exposed to the criticism of others.