The Dharmaguptaka School and the Tamraṣāṭīya School (Theravāda/Sthavira) are two sibling branches of the Vibhajyavāda school, which arose about 140 years after the Buddha’s Parinirvana. The Dharmaguptaka School was transmitted to China and then to Vietnam, bringing with it the Four-Part Vinaya, which most Vietnamese monastics study and practice. The Tamraṣāṭīya School was transmitted southward; Tamraṣāṭīya means “copper” (tamra) + “leaf” (ṣāṭīya), because their robes were reddish-yellow, resembling the color of copper. Later, it was renamed the Theravāda School. Comparing the two Vinaya collections, we see that the twenty sections (khandhakas) are almost identical:

• 1. Ordination Section – Great Section (Mahākhandhaka)
• 2. Recitation Section – Uposatha Section
• 3. Rains Retreat Section – Entering the Rains (vassa)
• 4. Invitation Section
• 5. Suspension Section
• 6. Robes Section – Medicine Section
• 7. Medicine Section – Kaṭhina Robe Section
• 8. Kaṭhina Section
• 9. Kuddāmiya Section
• 10. Campa Section
• 11. Kha-trach Section – Saṅghakamma Section
• 12. Human Section – Separate Residence Section
• 13. Depository Section – Miscellaneous Section
• 14. Value Section – Value Recitation Section
• 15. Schism Section
• 16. Dispute Resolution Section
• 17. Bhikkhunī Section
• 18. Dharma Section – Ritual Dharma Section
• 19. Lodging Section – Sleeping and Sitting Equipment Section
• 20. Miscellaneous Section – Miscellaneous Matters Section

Regarding cognition (pramāṇa), there are four main types:

1. Direct perception (pratyakṣa): correct intuition is true direct perception, incorrect is pseudo-direct perception.
2. Inference (anumāna): inductive/deductive reasoning, correct or incorrect.
3. Scriptural authority (āgama): revelation of the sages.
4. Non-valid cognition: mistaken pseudo-direct or inferential perception.

Along with these is “practical cognition,” that is, the practice itself. “Sanghakaya cognition” synthesizes direct perception, inference, scriptural authority, and practical cognition of the practicing community, and is the only “lamp” on which we can rely. Taking refuge in the Sangha means taking refuge in the collective insight, which does not oppose individual insight, because the insight of each practitioner is an integral part of the collective insight of the Sangha.