"grounding in the facts of the experiences of real individuals"

The problem with astrology is that there is no grounding in facts. The experience of individuals who believe in one type of astrology, where Venus is a planet of war, is different than the experience of individuals who believe in another type of astrology where Venus is a planet of peace. Their experience is of cultural conditioning where they have been told something arbitrary and they are fitting their feelings into that arbitrary scheme. Their experience is not based on fact but on an arbitrary belief shaped by their particular culture. It is like believing in one culture that white is the color of mourning and in another culture that black is the color of mourning. People experience their own myths, but you cannot say that it is a fact for all human beings.