Buddhi relates to Buddha, the one who is the great discerner and one of true intellect. The discerning discussed here is the refined ability to know what you are not, spoken as Neti, Neti - not this, not this. The Buddha was revered for his understanding of not being that of material nature, but a being who temporarily resided in form. The teachings of his renunciation of the benefits of the Brahmin society swapping it for a single loin cloth and begging bowl is the example of existing simply in the world without attachment, resistance or judgement.
It is of little surprise that the Buddhi Mudra is preformed with the thumb tip touching the pinky finger tip. In Ayurveda, the pinky is the water element of transformation. It is in the water element that the energy goes deep down and the time when the seed is dormant waiting for its next incarnation. The consciousness of the seed is hidden and still, then upon awakening, grows into its dharmic role (purpose) only to return to a dormant seed yet again. This expression is of the souls consciousness dwelling within the changing life cycle of a seed and a plant. The consciousness is not the seed nor the plant, Neti Neti. A human who remembers their being-ness (verb) in all states and cycles of matter is a great discerner. Preform this mudra each day as you contemplate that which you are and are not.
