The Pali commentaries often gloss tathāgata (“realized one”) with satta (“living being”). This happens especially, but not solely, in the context of the tetralemma regarding the survival of the tathāgata after death.
Analayo (Comparative Study, vol 1. p 391) gives some examples:
In regard to the destiny of a Tathāgata after death, one of the two Saṁyukta-āgama parallels to the Aggivacchagotta-sutta (SĀ2 196 at T II 445a18) speaks of the destiny of the “self of beings” or the “soul of beings”. This presentation parallels an explanation found in the Pāli commentarial tradition, which understands occurrences of the word Tathāgata in the context of this fourfold presentation to stand for a “living being”.
On the last point he notes:
E.g., Sv I 118,1: satto tathāgato ti adhippeto. This explanation seems to be standard for commenting on the tetralemma, cf. also Ps III 141,21: tathāgato ti satto, a formulation found similarly in Spk II 201,4 and Mp IV 37,22; on this commentarial gloss cf. also Gnanarama 1997: 236-237, Karunadasa 2007: 7-12, and Manda 2005. When it comes to occurrences of the term Tathāgata in contexts not related to the tetralemma, the commentaries record two possible meanings, namely either a living being in general or else an arahant, cf., e.g., Ps II 117,13: satto pi tathāgato ti adhippeto, uttamapuggalo khīṇāsavo pi, an understanding also reflected in Nidd-a I 193,24 and PaEis-a II 453,24: tathāgato ti satto, arahan ti eke.
Why, though, is a “realized one”, a term well-established as indicating either the Buddha or arahants in general, glossed as if it meant any sentient being? In particular, why is this introduced in the context of the tetralemma, which seems to be precisely about the destiny of an awakened one?
The commentary often supplies mere verbal glosses, where it simply recasts the word in another way as a synonym. The words tathāgata and satta appear to be such a case.
- Tathāgata has two elements. Tathā means “so, thus, true; real; actual”, while the suffix -gata means one who has come to be in such a state.
- Satta likewise has two elements. The root as means “existent, true, real” and is thus a synonym of tathā. The word is formed with the addition of the abstract ending -tta indicating “one in the state (of being)”.
The two words are applied in very different ways. We never find satta by itself used for an enlightened being. Nor, despite the commentary, do we find tathāgata in the sense of any sentient being. Thus they are verbal synonyms but not semantic synonyms.
I wonder whether this gloss began life as simple verbal resolution to explain the compound tathā-gata as sa-tta, to which later the applied sense of satta as “sentient being” was imported.
