Samkhya Karika 29

स्वालक्षण्यं वृत्तिस्त्रयस्य सैषा भवत्यसामान्या ।
सामान्यकरणवृत्तिः प्राणाद्या वायवः पञ्च ॥ २९ ॥

svālakṣaṇyaṁ vṛttistrayasya saiṣā bhavatyasāmānyā ।
sāmānyakaraṇavṛttiḥ prāṇādyā vāyavaḥ pañca ॥ 29 ॥

svālakṣaṇyaṁ=their own characteristics; vṛttiḥ=its respective function; trayasya=of the three (mind, ego, intellect); sā=that (vritti); eṣā=that (pointing to the same vritti); bhavati=is; asāmānyā=peculiar (to each); sāmānyā=common; karaṇa=of the instruments; vṛttiḥ=function; prāṇādyāḥ=prana etc.; vāyavaḥ=airs (pranas) pañca=five

Of the three (internal instruments – mind, ego, intellect) the functions are their respective characteristics; these are peculiar to each. The common functions of the three instruments are “prana” and the rest of the five vital airs.

Functions of the three inner instruments (antah-karana) – intellect, ego and the mind – are described in this karika. The karika states that the characteristics of the three that have been described earlier are also their functions. These functions are specific (asāmānyā ) to each of the three instruments. In karika 23, the nature of the intellect was defined as “ascertainment” (adhyavasāya) which is also its function. Similarly, in karika 24, the nature of the ego was given as “self-assertion” (abhimāna) which is also its function. In karika 27, the nature, and thus the function, of the mind was given as “determination” (saṁkalpaka).

Let’s take an example to understand how these three internal organs work together. Let’s say I am looking at a mango. The eyes, organ of perception, bring an image of the mango to the mind. The mind has to look into the memory to compare the image to something similar experienced previously. Based on the memory it makes the determination that it is a mango and hands it over to the ego. The ego goes back into the memory and notices that the previous experience was pleasant, and so, it would like to eat the mango. It then passes the information to the intellect. As we all know, there is always a struggle that goes on between the ego and the intellect. If the ego is dominant, the intellect may follow the “directive” from the ego and decide to eat the mango. On the other hand, if the intellect is dominant, it will analyze the situation and then decide whether to eat the mango or not. If I am diabetic, the intellect may decide not to eat the mango because of its sugar content. If all is well, it may decide to eat and enjoy the mango.

After describing the function specific to each of the three inner instruments, in the second part of the verse, the karika talks about the function that is common to all three. That function is the activity of the five vital airs, the prana etc. These vital airs are essential for the existence and functioning of the three internal organs. V. Mishra provides the location of the five vital airs as follows:

• Prana: located at the tip of the nose, the heart, the navel, feet and the thumb
• Apana: located at the neck, the back, the feet, the anus, the procreative organ, and the sides
• Samana: in the heart, the navel and the joints
• Udana: in the heart, throat, palate, head and between the eyebrows
• Vyana: in the skin

Gaudapada goes on to describe their function as follows:

• Prana: perceptible in the mouth and the nose, it gives vitality and motion to all organs.
• Apana: has its movement downwards.
• Samana: situated in the central part of the body, it circulates the nutrients throughout the body.
• Udana: has its movement upwards; it is in the space between the navel and the head.
• Vyana: pervades the entire body.

There is no common understanding among the commentators as to whether the function of the pranas is common to all thirteen organs or only the three inner instruments mentioned earlier. The karika seems to imply the latter. However, given that these five airs are essential for the survival and function of all the thirteen organs, I tend to agree with the former.