"Human evolution is a downward descent from the Universal One to separation; and then a stepwise ascent in conscious freedom to knowledge of one's connection to the universal. For this reason, seen from the mental plane, for human beings a dead stone is a model of higher life. In the stone the entire context and cosmic connections are still preserved; the causal law alone is at work in a stone. The external world provides the cause for the stone's movement. The stone extends from the mental plane into the physical because its pure thought resides serenely in it. Thus the Sun, which is at home as the physical image of the Logos in the mental plane, and the entire mineral kingdom are to be seen as a great laboratory for physical and chemical forces."
Source: Concerning the Astral World and Devachan, p. 135