[Advaita-l] Bayesian Evaluation of Sankara's Chronology

[Rajaram Venkataramani]

Four hypotheses are commonly proposed to explain Śaṅkara’s chronology and
the structure of the corpus attributed to him: H1 Ādi Śaṅkara lived about
2500 years ago and Abhinava Śaṅkara lived about 1200 years ago; H2 Śaṅkara
lived about 1200 years ago; H3 Śaṅkara lived about 2500 years ago; and H4
Śaṅkara lived about 2500 years ago, with his works undergoing redaction
around 1200 years ago. This evaluation adopts a Bayesian framework that
gives substantial epistemic weight to sampradāya chronology, accepts
continuity of philosophical doctrines, and incorporates normative Indian
textual transmission practices.

H1: Ādi Śaṅkara (2500y) and Abhinava Śaṅkara (1200y)
This hypothesis preserves the traditional claim of an ancient Ādi Śaṅkara
while explaining later polemical material through a second historical
figure bearing the same honorific title. The reuse of authoritative names
across centuries is well attested in Indian intellectual history, lending
this proposal genuine plausibility. However, the hypothesis requires a
relatively complex historical reconstruction involving conflation of texts
and teachings without clear internal criteria for separating their
contributions. While coherent and tradition-compatible, it introduces more
structural complexity than the evidence strictly demands. Posterior
plausibility: ~10%.

-H2: Śaṅkara lived about 1200 years ago.
This hypothesis benefits from a straightforward reading of the received
texts, particularly references to Buddhist philodophers Nāgārjuna and
Dharmakīrti, and from the apparent maturity of the philosophical debates.
Its explanatory simplicity is a genuine strength. Nevertheless, when
sampradāya chronology is treated as a serious evidentiary source and
doctrinal continuity is acknowledged, this position becomes less
persuasive. It marginalizes traditional memory and assumes, without
independent support, that philosophical sophistication requires late
dating. Accordingly, it remains viable but comparatively weak. Posterior
plausibility: ~15%.

H3: Śaṅkara lived about 2500 years ago.
This hypothesis aligns strongly with sampradāya testimony and is well
supported by the principle of continuity, which allows philosophical
positions to long predate the figures with whom they are later associated.
It preserves the integrity of traditional chronology and avoids multiplying
historical agents. Its principal limitation is that it does not, by itself,
fully explain the appearance of refetences to later works, relying instead
on implicit assumptions about glossing or attribution. Posterior
plausibility: ~15%.

-H4: Śaṅkara lived about 2500 years ago, and his works were redacted around
1200 years ago.
This hypothesis synthesizes the strengths of all the preceding positions
while minimizing their weaknesses. It preserves sampradāya chronology,
fully accommodates doctrinal continuity, and explicitly incorporates
well-established Indian śāstric practices of redaction, interpolation, and
polemical updating. Crucially, it explains the presence of later
philosophers in the corpus without multiplying historical figures or
discounting traditional testimony. Because it accounts for the entire
evidentiary set with the least residual tension and the greatest
explanatory economy, it emerges as the most convincing explanation.
Posterior plausibility: ~60%.

-Conclusion

When evaluated within a Bayesian framework that respects traditional
chronology, continuity of ideas, and historical transmission practices,
posterior plausibility increases steadily from H1 through H4. Among the
four, H4 stands out as the most robust and comprehensive account,
preserving the antiquity of Śaṅkara while realistically acknowledging the
layered nature of the textual tradition that bears his name.