Theosophy
In Blavatsky's synthesis of eastern philosophy with western esotericism, the union of the higher Manas with the Buddhi (i.e. the essential nature of the fifth, along with the sixth, of the seven principles) is referred to as the Causal Body (Blavatsky, Key to Theosophy, pp. 121, 174). This higher principle is contrasted with the lower, the Kama-Manas, which is the seat of lower passions. In the Theosophy of Annie Besant and C. W. Leadbeater, the "Causal Body" refers not to the "Buddhi-Manas" but to Blavatsky's "Higher Manas" alone. This is also referred to as the "Higher Mental", "Abstract Mind" (as opposed to Lower Mental or "Concrete Mind"), or "Causal Body". It is considered the highest subtle body, beyond even the mental body. As with all the vehicles of consciousness, the Causal Body is associated with an objective or cosmic plane, in this case the Causal plane. A detailed definition of the Causal Body, is provided by A. E. Powell, who has brought together information in the works of Besant and Leadbeater in a series of books on each of the subtle bodies.
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