the grave numen, represented as the black horse, is resurrected and becomes visible… the black horse represents the evil passions. If one follows the evil passions, one is lead into the desert.
Edinger reads the black horse as the grave numen revived by consciousness’s descent, tracing the symbol to Plato’s charioteer and arguing that pursuing the dark horse through the desert ultimately leads to discovery of the Self.
, The Mysterium Lectures: A Journey Through C.G. Jung’s Mysterium Coniunctionis, 1995thesis