by Swami Sivananda
Mundaka III.1.1 and Katha I.3.1 constitute one Vidya.
Iyadamananat III.3 34 (393)
Because (the same thing) is described as such and such.
Iyat: so much only, this much; Amananat: on account of being mentioned in the scripture.
We read in the Mundaka Upanishad "Two birds of beautiful plumage, inseparable friends, cling to the same tree. One of them eats the sweet and bitter fruits there of, the other looks on without eating" (Mun. Up. III.1.1). The same Mantra is found in the text of Svetasvatara Upanishad (IV.6).
Again we have, "There are the two enjoying the fruits of their good deeds, entered into the cave, dwelling on the highest summit. Those who know Brahman call them shade and light, likewise those householders who perform the Trinachiketa sacrifice" (Katha Up. I.3.1).
The doubt here arises, do we have in these two texts two different Vidyas or one only?
The Purvapakshin or the opponent maintains that these are two Vidyas, because there are different objects of meditation. The Mundaka text declares that only one eats the fruit, while the other does not. Katha text says that both of them enjoy the fruits of their good actions. So the object of meditation is not the same. As the objects of knowledge differ in character, the Vidyas themselves must be looked upon as separate.
This Sutra refutes it and declares that they form one Vidya, because both describe the same Lord as existing thus and thus, i.e. in the form of the individual soul. The purpose or aim of the two Sruti passages is to teach about the Highest Self or Para Brahman and show the identity of the Jiva and Para Brahman.
As the word Dvau, i.e., two is used in the two Srutis we must realise that they refer to the same Vidya. Though the Mundaka text says that one bird (the individual soul) eats the fruits of actions and the other bird looks on without eating and though the latter passage refers to the two as eating fruits, the Vidyas are the same as they refer to the same entity. Just as when in a group one carries an umbrella we say umbrella-holders go, even so the Para Brahman also is described as eating fruits. The context refers clearly to the eternal and Supreme Brahman (Aksharam brahma yat param).
The Katha Upanishad text intimates the same highest Brahman which is above all desires. As it is mentioned together with the enjoying individual soul, it is itself metaphorically spoken of as enjoying, just as we speak of the 'men with the umbrella' although only one out of several carries an umbrella. All this has been explained at length under I.2.11.
Therefore, the Vidyas are one only, as the object of meditation or Knowledge is one.