The Intention as "Go-Between"
Foundations of Internal Alchemy: The Taoist Practice of Neidan, by Wang Mu, page 40
The Intention (yi) is the operation of Spirit; the so-called True Intention (zhenyi) means that the thought activity issues from the Spirit. If we identify the mind with the brain, then the function of the brain is the Spirit, and its thinking faculty is the Intention. If one controls the joining of the Three Treasures by means of the Intention, then one can activate its intermediary function among the Three Treasures [i.e., Essence, Breath, and Spirit].
For this reason, the Intention is also called "go-between" and Intention-Soil (yitu). The meaning of "go-between" is that it introduces Yin and Yang to one another for their conjunction. Therefore the alchemical texts also call it Yellow Dame (huangpo): "yellow" indicates that it pertains to the central agent Soil, and "dame" means that it is the "match-maker" (meipo), a metaphor for the intermediary that allows the joining of Yin and Yang.
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