Astrology is broadly defined as the study of the correlation between celestial and earthly events.
It is based on the premise that when something happens in the sky, and event that has similar symbolic meaning will also occur on Earth.
Astrologers have historically been divided into two major camps when it comes to their views regarding the mechanism underlying astrology:
1) The first camp views the planets and other celestial objects as being capable of correlating with earthly events without necessarily causing those events to occur. Therefore they adhere to the view that there is no causal mechanism underlying astrology, but instead that it works as a result of symbolic correlations that are not causal in nature.
2) The second camp views the planets and other celestial objects as literally causing events on Earth to happen through some sort of causal force or mechanism that they emit. Those in this camp view astrology as working through some sort of underlying causal mechanism, although the nature of the mechanism is sometimes said to be a known force, such as electromagnetism, and other times an unknown force that hasn’t been properly discovered or understood yet.
The commonality between the two views is that they both accept that celestial objects bodies regularly correlate with terrestrial events. Practically speaking, astrologers who adhere to one view or the other essentially practice astrology in the same way, as most of the techniques could be conceptualized within the context of either framework.