Discussion around Sosan, also known as Sengcan, tends to focus less on his spiritual message and more on the historical and textual framework that later generations built around his name. Traditional biographies, preserved in works compiled long after his lifetime, are now widely regarded as highly legendary, with many details seen as hagiographical rather than historically secure. Because reliable records are so sparse, some scholars even question whether he can be identified as a clearly historical individual, or whether his figure was shaped to serve later doctrinal and institutional needs. Within this perspective, his designation as the “Third Patriarch” appears less as a neutral historical fact and more as part of a lineage narrative crafted to establish legitimacy for emerging Chan communities. The criticism here is not directed at the depth of the teaching itself, but at the way institutional authority and spiritual ancestry were retrospectively organized.

A related area of scrutiny concerns the text traditionally associated with his name, the *Xinxin Ming* (“Faith in Mind” or “Inscription on Faith in Mind”). While this work is deeply revered and widely read, modern scholarship often doubts that Sosan himself composed it, pointing instead to linguistic and doctrinal features that suggest a later date and a more mature Chan vocabulary. Some scholars propose that the text may have been composed after his presumed era, or at least significantly shaped by later hands, and then retroactively attributed to him. This does not diminish the spiritual resonance of the verses, but it does cast the attribution as part of the same lineage-building process that elevated Sosan’s status within the Chan tradition.

As for the teachings themselves, especially as expressed in the *Xinxin Ming*, criticism tends to arise not from historical Chan communities but from later interpretive debates. The strong emphasis on non-duality and “no picking and choosing” has occasionally been read as encouraging philosophical quietism or passivity, and some have warned that, taken out of context, such lines might lend themselves to moral relativism or a kind of spiritual bypassing. Yet these concerns are directed more at certain ways of reading the text than at Sosan as a distinct doctrinal innovator, since there is little record of polemical or sharply distinctive positions uniquely tied to his name. In the broader landscape of early Chan, his legacy is thus seen as representative of mainstream Mahāyāna and early Zen sensibilities, while the real controversies cluster around questions of historicity, authorship, and the politics of lineage rather than around the heart of the teaching itself.