Disclaimer: I am neither an atheist nor against the devotees of Krishna. I am strictly going by the narratives available in texts/inscriptions.
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(A) In the brief narration of presently available Mahabharata (Chapter 61 of Adiparva), Vaisampayana mentions Vāsudeva, the son of Vasudeva, with 4 names.
Hṛṣīkēśa (हृषीकेश) - 1 time, Kṛṣṇa (कृष्ण) - 1 time, Vāsudeva (वासुदेव) - 2 times, Kēśava (केशव) - 1 time.
Contrary to popular perception, Sage Vyasa did not use the names Hṛṣīkēśa (हृषीकेश), Kṛṣṇa (कृष्ण) and Kēśava (केशव), in Chapter 61 of Adiparva,, to indicate Vishnu/Narayana.
This attribution to Vishnu/Narayana is a later date development.
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(B) In view of the following reasons, I am inferring that Vāsudeva, the Mahabharata character and Krishna mentioned in Gāthā Saptaśatī are different characters, but were merged into one at a later date to add the childhood narratives of Vāsudeva, the Mahabharata character.
- Pāṇini (~600 BC) mentions in his Aṣṭādhyāyī (Sutra 4.3.98) about Vāsudeva, the Mahabharata character, as the divinity (Vāsudevārjunābhyāṃ vun).
- The core Mahabharata also mentions as Vāsudeva only, and Krishna was used to indicate only his complexion - as also Draupadi as Kṛṣṇā, Vyasa/Dvaipāyana as Kṛṣṇadvaipāyana.
- Further, core Mahabharata does not mention the Śṛṅgāra rasa (romantic relationship between lover and beloved) part of Vāsudeva, but projected him as a great strategist, the person who adhered to TRUTH and DHARMA, a warrior, great charioteer
- The Heliodorus pillar (c. 110 BCE) inscription on the column explicitly names Vāsudeva as Devadeva ("God of Gods"), indicating that Vāsudeva, the Mahabharata character is known by this name only.
- However, Gāthā Saptaśatī (~100 AD) mentions Rādhā and Kṛṣṇa and in this text there is no divinity attached to Kṛṣṇa, but only mentions as the lover of Rādhā
- If we exclude writings in Harivamsha, the subsequent addition to Mahabharata, Puranas and Ashthapadi of Jayadeva, which projected the childhood/Śṛṅgāra rasa stories of Kṛṣṇa and the unified form of Vāsudeva and Kṛṣṇa, we can find that Vāsudeva, Mahabharata character, is different from Krishna in Gāthā Saptaśatī
