Verse 29: What does the mind do?

svā-lakṣanyaṃ vṛttiḥ trayasya sā-eṣā bhavati-asāmānya |
sāmānya-karaṇa-vṛttiḥ prāṇa-ādyā vāyavaḥ pañca ||

sva – one’s self
lakṣaṇa – characteristic
vṛtti – fluctuation
traya – the three
asāmānya – special (not common)

sāmānya – alike (common)
prāṇa – vital force /breath
pañca – five

Mind functions alongside Discerning Intelligence and the I-Principle.

1. Mind functions together with intelligence (Mahat – verse 23), the I-principle (Ahamkara – verse 24). They form a threesome of internal organs.
2. They are considered internal because they perceive the ten objects-of-sense (see verse 26). The ten objects-of-sense are the objects of the internal organs.
3. The ten objects-of-sense are considered external organs because their objects (the things they perceive and act on) are external.
4. Like the ten objects-of-sense, the three internal organs all specialize and have a unique function.
5. They do what they are and they are what they do and therefore each has an exclusive function:
   1. Manas (mind) deteremines: that is chocolate.
   2. Ahamkara (I-principle) applies that which Manas determines to self: I want chocolate.
   3. Mahat (intelligence) decides how to relate to what Ahamkara has placed in relation to self : have some.
6. For the three to function Prana needs to be present.
   1. The word Prana has two meanings.
      1. It describes a group of five “airs” each of which is located in different places in the body and have different functions.
      2. It is also one (arguably a primary) of these five “airs.”
   2. Prana is intimately associated with breath. When breath is present Prana is present. If breath is absent it is because Prana is absent.
7. The existence of the three internal organs is dependent on Prana. When Prana is present the three exist. When Prana is absent the three cease to exist