In the old discussion about Bhikkhu Analayo’s paper about that infamous “radiant mind” passage, there was an old Youtube video posted of Bhante Sujato discussing the “original mind” concept in Thai Buddhism, and specifically in the Thai Forest Tradition.
This topic is fascinating from a number of different angles. As mentioned, it’s very difficult to get a sense of what someone actually means when they are discussing rarefied states of mind or meditation phenomena like that. When someone uses a term like “consciousness” or “mind,” what they actually mean can vary quite a lot.
Then there is the historical matter of how these interpretations entered Thai Buddhism. There was some mention in the video about Mahayana in Thailand in the past. Indian Mahayanists were known to be propagating similar ideas in Southeast Asia. Some translators like Samghabara, Mandrasena, and Paramartha, moved from India to Funan, and then eventually into China.
Paramartha in particular propagated Tathagatagarbha type school of Yogacara. Those ideas eventually also took hold in China and became codified in the Chan Buddhism. It would also not surprise me if later Chan Buddhists such as Xuyun had some influence in the early 20th century. For example:
In 1907 (age 68), at Thailand’s Longquan temple, while delivering discourse on Pumenpin (the Universal Gate Chapter of the Lotus Sūtra) following his discourse on Dizang-jing (the Earth Repository Sūtra), [Xuyun] entered into samādhi, forgetting about his speech. He stayed in concentration for nine days, which made a stir in the capital city of Thailand.
All of this is really just to ask if, in 2021, we know any more about what those connections were?
Is it any clearer today how those ideas about the mind entered the Thai Forest Tradition?