In the historic region of Mithila, local historians have uncovered a 9th-century manuscript titled Nyaya-Kaustubha. This treatise on Indian logic (Nyaya) provides a refined analysis of the five-membered syllogism, offering new perspectives on the process of logical deduction (anumana) and the nature of fallacies.
The text is attributed to a scholar named Jayanta-Bhatta II and explores the epistemological foundations of debate. By examining the conditions of 'Valid Knowledge', the manuscript serves as a vital link between early Nyaya works and the later Navya-Nyaya school, illustrating the evolution of formal logic in the Indian subcontinent.