Guham pravistavatmanau hi taddarsanat I.2.11 (42)

The two who have entered into the cavity (of the heart) are indeed the individual soul and the Supreme Soul, because it is so seen.

Another passage of the Kathopanishad is taken up for discussion. In the same Kathopanishad I-3-1 we read, "Having entered the cavity of the heart, the two enjoy the reward of their works in the body. Those who know Brahman call them shade and light: likewise those householders who perform the Trinachiketa sacrifice".

The doubt arises here whether the couple referred to are the individual soul and Buddhi (intellect).

In the passage under discussion, the couple referred to are the individual soul and the Supreme Self, for these two, being both intelligent selfs, are of the same nature. We see that in ordinary life also whenever a number is mentioned, beings of the same class are understood to be meant. When a bull is brought to us, we say 'bring another, look out for a second'. It means another bull, not a horse or a man. So, if with an intelligent self, the individual soul, another is said to enter the cavity of the heart, it must refer to another of the same class i.e. to another intelligent being and not to the intellect (Buddhi) which is insentient.

Sruti and Smriti speak of the Supreme Self as placed in the cave. We read in Kathopanishad I-2-12 "The ancient who is hidden in the cave, who dwells in the abyss". We also find in Taittiriya Upanishad II-1 "He who knows him hidden in the cave, in the highest ether" and "search for the self who entered into the cave". A special abode for the all-pervading Brahman is given for the purpose of conception and meditation. This is not contrary to reason.

Sometimes the characteristics of one in a group are indirectly applied to the whole group as when we say "The men with an umbrella" where only one has an umbrella and not the whole group. Similarly here also, though it is only one who is enjoying the fruits of actions both are spoken of as eating the fruits.

The word 'pibantau' is in the dual number meaning 'the two drink while as a matter of fact, the Jiva only drinks the fruit of his works and not the Supreme Self. We may explain the passage by saying that while the individual soul drinks, the Supreme Self also is said to drink because he makes the soul to drink. The individual soul is the direct agent, the Supreme Self is the causal agent that is to say the individual self directly drinks while the Supreme Self causes the individual soul to drink.

The phrases 'shade' and 'light' show the difference between the Infinite Knowledge of the Supreme Self and the finite knowledge of the Jiva, or that the Jiva is bound down to the chain of Samsara, while the Supreme Self is above Samsara.

We, therefore, understand by the 'two entered into the cave', the individual soul and the Supreme Self.
Another reason for this interpretation is given in the following Sutra.

Viseshanaccha I.2.12 (43)

And on account of the distinctive qualities (of the two mentioned in subsequent texts).

An argument in support of Sutra 11 is given.

This is clear also from the description in other portions of the same scripture viz. Kathopanishad.

Further the distinctive qualities mentioned in the text agree only with the individual soul and the Supreme Soul. Because in a subsequent passage (I-3-3) the characteristics of the two that have entered the cavity of the heart are given. They indicate that the two are the individual soul and Brahman. "Know that the Self to be the charioteer, the body to be the chariot." The individual soul is represented as a charioteer driving on through the transmigratory existence and final emancipation. Further it is said "He attains the end of his journey, that highest place of Vishnu" Katha Up. I-3-9. Here it is represented that the Supreme Self is the goal of the driver's course. The two are mentioned here as the attainer and the goal attained i.e. the individual soul or Jiva and the Supreme Soul or Brahman.

In the preceding passage (I-2-12) also it is said "The wise, who by means of meditation on his Self, recognises the Ancient who is difficult to be seen, who has entered into the dark, who is hidden in the cave of the heart, who abides in the abyss as God, he indeed leaves joy and sorrow far behind". Here the two are spoken of as the meditator and the object of meditation.

Moreover the Supreme Self is the general topic. It is therefore obvious that the passage under discussion refers to the individual soul and the Supreme Self.