by Swami Sivananda
The Purusha Vidya in the Chhandogya and the Taittiriya are not to be combined.
Purushavidyayamiva chetareshamanamnanat III.3.24 (383)
And (as the qualities) as (mentioned) in the Purusha-Vidya (of the Chhandogya) are not mentioned (in that) of the others (i.e., in the Taittiriya) (the two Purusha-Vidyas are not one; are not to be combined).
Parushavidyayamiva: as in the Purusha-Vidya (of the Chhandogya); Cha: and; Itaresham: of the others; Anamnanat: because of not being mentioned (in the Taittiriya).
The Purusha Vidya of the Chhandogya Upanishad and that of the Taittiriya Upanishad are now examined.
In the Rahasya-Brahmana of the Tandins and the Paingins (the Chhandogya) there is a Vidya treating of man in which man is identified with the sacrifice, the three periods of his life with the three libations "Man is the sacrifice".
In the Taittiriya Aranyaka (X.64) also occurs a similar Vidya "For him who knows thus the self of the sacrifice is the sacrificer, faith (Sraddha) is the wife of the sacrificer," etc.
The doubt here arises whether the two Vidyas are one, whether the particulars of the man-sacrifice given in the Chhandogya are to be inserted in the Taittiriya or not.
The fundamental attribute referred to is that man is identified with sacrifice in both. This Sutra declares that in spite of this, the two Vidyas are not one, because the details differ. The characteristics of the Purusha-Yajna of the Chhandogyas are not recognised in the Taittiriya text. The Taittiriya exhibits an identification of man with the sacrifice in which the wife, the sacrificer, the Veda, the Vedi, the sacrificial grass, the post, the butter, the sacrificial animal, the priest etc., are mentioned in succession. These particulars are not mentioned in the Chhandogya.
The two texts agree in identification of the Avabhritha ceremony with death. There are greater number of dissimilarities. The Taittiriya does not represent man as the sacrifice as the Chhandogya does.
Moreover the result of the Vidya in the Taittiriya is the attainment of the greatness of Brahman: "He obtains the greatness of Brahman". The result of the Vidya in Chhandogya is long life, "He who knows this lives on to a hundred and sixteen years."
Therefore, the two Vidyas are separate. "The particulars cannot be combined in the two places. The particulars mentioned in the Purusha-Vidya of Chhandogya, such as formulas of prayer, Mantras and so on are not to be combined with the Taittiriya text of the Vidya.