The Four Ethers
Throughout the lectures of the Agriculture Course mention is made of the working of the four ethers; warmth, light, tone and life ether. The ethers act into the four elemental states of fire, air, water and earth as ordering, enlivening life-forces. Warmth ether may be compared to the warmth of enthusiasm, the willingness to sacrifice and the developing warmth that brings things to maturity, light ether has a quality of wisdom that is actively creative, which is similar to when a new idea lights up in us, tone ether arranges matter into ordered and harmonious relationships, while life ether embodies the essence of something, its wholeness, living meaning or Word. As bearers of cosmic formative forces, there is a relationship between the the ethers and the various realms of the spiritual world: light ether and the elemental-astral world, tone ether and lower Devachan (the harmony of the spheres), and life ether and higher Devachan. See The Ethers and the Spiritual Worlds.