Yogacara is often interpreted as a form of Idealism due to its main doctrine, the view that only ideas or mental images exist (vijñapti-mātra). Some Tibetan philosophers interpret Yogācāra as the view that the mind (citta) exists in an ultimate sense, because of this, it is often seen as inferior to Madhyamaka. However, other Tibetan thinkers deny that the Indian Yogacāra masters held the view of the ultimate existence of the mind, and thus, they place Yogācāra on a level comparable to Madhyamaka. This perspective is common in the Nyingma school, as well as in the work of the Third Karmapa, the Seventh Karmapa and Jamgon Kongtrul. Madhyamaka () - The philosophy of Nāgārjuna and Āryadeva, which affirms that everything is empty of essence (svabhava) and is ultimately beyond concepts. There are various further classifications, sub-schools and interpretations of Madhymaka in Tibetan Buddhism and numerous debates about various key disagreements remain a part of Tibetan Buddhist scholasticism today. One of the key debates is that between the rangtong (self-empty) interpretation and the shentong (other empty) interpretation. Another major disagreement is the debate on the Svātantrika Madhyamaka method and the Prasaṅgika method. There are further disagreements regarding just how useful an intellectual understanding of emptiness can be and whether emptiness should only be described as an absolute negation (the view of Tsongkhapa). The tenet systems are used in monasteries and colleges to teach Buddhist philosophy in a systematic and progressive fashion, each philosophical view being seen as more subtle than its predecessor. Therefore, the four tenets can be seen as a gradual path from a rather easy-to-grasp, "realistic" philosophical point of view, to more and more complex and subtle views on the ultimate nature of reality, culminating in the philosophy of the Mādhyamikas, which is widely believed to present the most sophisticated point of view. Non-Tibetan scholars point out that historically, Madhyamaka predates Yogacara, however. Texts and study Study of major Buddhist Indian texts is central to the monastic curriculum in all four major schools of Tibetan Buddhism. Memorization of classic texts as well as other ritual texts is expected as part of traditional monastic education. Another important part of higher religious education is the practice of formalized debate. The canon was mostly finalized in the 13th century, and divided into two parts, the Kangyur (containing sutras and tantras) and the Tengyur (containing shastras and commentaries). The Nyingma school also maintains