Ajñana was a Śramaṇa school of radical Indian skepticism and a rival of early Buddhism and Jainism. They held that it was impossible to obtain knowledge of metaphysical nature or ascertain the truth value of philosophical propositions; and even if knowledge was possible, it was useless and disadvantageous for final salvation. They were seen as sophists who specialized in refutation without propagating any positive doctrine of their own. Jayarāśi Bhaṭṭa (fl. c. 800), the author of the skeptical work entitled "Tattvopaplavasiṃha" ("The Lion that Devours All Categories"/"The Upsetting of All Principles"), has been seen as an important Ajñana philosopher.