93-94. The inner organ (Antahkarana) is called Manas, Buddhi, ego or Chitta, according to their respective functions: Manas, from its considering the pros and cons of a thing; Buddhi, from its property of determining the truth of objects; the ego, from its identification with this body as one’s own self; and Chitta, from its function of remembering things it is interested in.
95. One and the same Prana (vital force) becomes Prana, Apana, Vyana, Udana and Samana according to their diversity of functions and modifications, like gold, water, etc.
96. The five organs of action such as speech, the five organs of knowledge such as the ear, the group of five Pranas, the five elements ending with the ether, together with Buddhi and the rest as also Nescience, desire and action – these eight "cities" make up what is called the subtle body.
97. Listen – this subtle body, called also the Linga body, is produced out of the elements before their subdividing and combining with each other, is possessed of latent impressions and causes the soul to experience the fruits of its past actions. It is a beginningless superimposition on the soul brought on by its own ignorance.
98-99. Dream is a state of the soul distinct from the waking state, where it shines by itself. In dreams Buddhi, by itself, takes on the role of the agent and the like, owing to various latent impressions of the waking state, while the supreme Atman shines in Its own glory – with Buddhi as Its only superimposition, the witness of everything, and is not touched by the least work that Buddhi does. As It is wholly unattached, It is not touched by any work that Its superimpositions may perform.
100. This subtle body is the instrument for all activities of the Atman, who is Knowledge Absolute, like the adze and other tools of a carpenter. Therefore this Atman is perfectly unattached.
Source: Vivek Choodamani By Adi Sankaracharya, Translated by Swami Madhavananda
Published by Advaita Ashram, Kolkatta