Jayarāśi Bhaṭṭa (fl. c. 800) was a sceptical (ajñana) Indian philosopher, author of the Tattvopaplavasiṃha (tattva-upa.plava-siṃha "The Lion that Devours All Categories"/"The Upsetting of All Principles").
The text was discovered in a single manuscript in the 20th century. Its original 1940 edition attributed it to the materialist Charvaka school, but scholarly opinion on this point remains divided. The work is primarily epistemological in nature, reminiscent of the sceptical philosophy of David Hume.
The manuscript of Tattvopaplavasimha was discovered in 1926 and published in 1940 by Saṁghavī and Pārīkh. The book examines epistemology, where Jayarāśi considers the pramāna (sources of knowledge) accepted in establishing conclusions (perception, inference, and testimony), and proves that none of them are sufficient for establishing knowledge. Inference relies on inductive reasoning, which cannot be shown to be universal premises. Testimony requires the reliability of the witness, which must be established by another of the pramāna. Even direct perception cannot establish truth, because it requires that the perception not be erroneous or illusory, which also cannot be established. Therefore, Jayarāsi argues that none of the sources of knowledge are valid, and nothing can be known for certain.
Jayarāsi challenged the āstika establishment's belief in supernatural beings by attacking their epistemology. Since none of the sources of knowledge are valid, how can anything be said about these beings? Therefore, he argued for the reasonability of atheism, and that happiness in one's life is the most reasonable goal. Jayarasi represented a philosophy of extreme skepticism, claiming no school of philosophy can claim its view of reality as knowledge, including the Cārvāka itself; however, because Cārvāka philosophy represents common sense, it could be used as a guide.
Association with Cārvāka
Tattvopaplavasimha is regarded by some authors as belonging to the Cārvāka (Lokāyata) school. Sukhlalji Sanghvi and Rasiklal Parikh, D.R. Shastri, Eli Franco, Karin Presidendanz, and Piotr Barcelowicz are examples. Franco (1994), for instance, says "Tattvopaplavasimha is the only Lokayata text which has been discovered so far".
This view is opposed by scholars including Karel Werner, Walter Ruben, K.K Dixit, Debiprasad Chattopadhyaya, M. K. Gangopadhyaya, A H Salunkhe, and Ramkrishna Bhattacharya. Werner (1995), for instance, is sceptical of the claim that Tattvopaplavasimha is a Cārvāka text. He however accepts that the text is an important secondary source for Cārvāka.
According to Debiprasad Chattopadhyaya, "Jayarāśi, who claims to be intellectually superior to Bṛhaspati, could ... hardly be a follower of Bṛhaspati himself, i.e., could hardly be the leader of any imaginary offshoot of the Cārvāka or Bārhaspatya system". In support of his view that Tattvopaplavasimha is not a Cārvāka/Lokāyata text, Chattopadhyaya says "it is moreover necessary to remember that Jayarāśi claims as his final achievement the annihilation of the vanity of the Pāṣaṇḍin [pākhaṇḍin]-s (Tattvopaplavasiṃha Baroda edition p.125). Now whatever might have been the exact meaning of the word pāṣaṇḍin, it could by no stretch of imagination have excluded the Lokāyatikas and Cārvākas." 
Salunkhe also holds that Jayarasi Bhatta did not belong to the Cārvāka school of philosophy as he denies even Pratyakşa pramana and four Mahābhūtas that Cārvāka had accepted. He notes Jayarsi as an agnostic and anti-philosophic rather than a materialistic Lokāyatika.
Ramkrishna Bhattacharya adduces an argument from within the text itself to refute the claim that Tattvopaplava-siṃha is a Cārvāka text. He says, "there is indeed a Cārvāka at the very beginning of the Tattvopaplava-siṃha. But he is not Jayarāśi, but another person who is presented as a Cārvāka out to challenge Jayarāśi’s doctrine of upsetting tattva as such. This objector has to be a Cārvāka, for who but a Cārvāka would refer to the basic premises of materialism and stand upon them? The presence of this objector and the way Jayarāśi gets into controversy with him clearly indicate that Jayarāśi himself was not a Cārvāka or did not even belong to ‘a section of the Cārvāka’ (cārvākaikadeśya)".
- dated to ca. 770–830 by Franco (1994) and ca. 800–840 by Balcerowicz (2011).
- Franco 1994, p. 554
- Chattopadhyaya 1964, p. 222–223
- Chattopadhyaya 1964, p. 223
- Salunkhe 2009, p. 36
- Bhattacharya, Ramkrishna. Tattvopaplavavāda of Jayarāśi and its Alleged Relation to the Cārvāka/Lokāyata. Retrieved 06 February 2015.
- Balcerowicz, Piotr, "Jayarāśi", The Stanford Encyclopedia of Philosophy (2011).
- Chattopadhyaya, Debiprasad (1964). Indian Philosophy: A Popular Introduction. Delhi: People’s Publishing House.
- Franco, Eli (1994). Perception, Knowledge, and Disbelief: A Study of Jayarasi's Scepticism. Delhi: Motilal Banarasidas.
- Narayan Campawat, "Jayarasi Bhatta", in Great Thinkers of the Eastern World, Ian McGready, ed., New York: Harper Collins, 1995, pp. 202–206. ISBN 0-06-270085-5
- review: Karel Werner, Bulletin of the School of Oriental and African Studies, University of London (1995)
- Saṁghavī, Sukhlāljī; Pārīkh, Rasiklāl C. (eds.): Tattvopaplavasimha of Shri Jayarasi Bhatta. Edited with an introduction and indices. Gaekwad Oriental Series 87, Oriental Institute, Baroda 1940 [Reprinted: Bauddha Bharati Series 20, Varanasi 1987].
- Salunkhe, AH (2009). Astikshiromani Charvaka (in Marathi). Satara: Lokayat Prakashan.
- Werner, Karel, 1995, “Review of Eli Franco: Perception, knowledge and disbelief: a study of Jayarāśi's scepticism, Delhi, Motilal Banarsidass 1994”, Bulletin of the School of Oriental and African Studies, 58(3): 578.
- Tattvopaplavavāda of Jayarāśi and its Alleged Relation to the Cārvāka/Lokāyata Ramkrishna Bhattacharya