The Abhidharma are ancient (third century BCE and later) Buddhist texts which contain detailed scholastic presentations of doctrinal material appearing in the Buddhist sutras. It also refers to the scholastic method itself as well as the field of knowledge that this method is said to study. Bhikkhu Bodhi calls it "an abstract and highly technical systemization of the [Buddhist] doctrine," which is "simultaneously a philosophy, a psychology and an ethics, all integrated into the framework of a program for liberation." According to Peter Harvey, the Abhidharma method seeks "to avoid the inexactitudes of colloquial conventional language, as is sometimes found in the Suttas, and state everything in psycho-philosophically exact language." In this sense, it is an attempt to best express the Buddhist view of "ultimate reality" (paramartha-satya). There are different types of Abhidharma literature. The early canonical Abhidharma works (like the Abhidhamma Pitaka) are not philosophical treatises, but mainly summaries and expositions of early doctrinal lists with their accompanying explanations. These texts developed out of early Buddhist lists or matrices (mātṛkās) of key teachings. Later post-canonical Abhidharma works were written as either large treatises (śāstra), as commentaries (aṭṭhakathā) or as smaller introductory manuals. They are more developed philosophical works which include many innovations and doctrines not found in the canonical Abhidharma. Abhidharma remains an important field of scholarship among both Theravāda and Mahayana Buddhists. Definition The Belgian Indologist Étienne Lamotte described the Abhidharma as "Doctrine pure and simple, without the intervention of literary development or the presentation of individuals" Compared to the colloquial sutras, Abhidharma texts are much more technical, analytic and systematic in content and style. The Theravādin and Sarvastivadin Abhidharmikas generally considered the Abhidharma to be the pure and literal (nippariyaya) description of ultimate truth (paramattha sacca) and an expression of perfect spiritual wisdom, while the sutras were considered 'conventional' (sammuti) and figurative (pariyaya) teachings, given by the Buddha to specific people, at specific times, depending on specific worldly circumstances. They held that Abhidharma was taught by the Buddha to his most eminent disciples, and that therefore this justified the inclusion of Abhidharma texts into their scriptural canon. According to Collett Cox, Abhidhamma started as a systematic elaboration of the teachings of the suttas, but later developed independent doctrines. The prominent Western scholar of Abhidharma, Erich Frauwallner has said that these Buddhist systems are "among the major achievements of the classical period of Indian philosophy." Two interpretations of