Later philosophers of the Madhyamaka school built upon Nagarjuna's analysis and defended Madhyamaka against their opponents. These included Āryadeva (3rd century CE), Nāgārjuna's pupil; Candrakīrti (600–c. 650), who wrote an important commentary on the Mūlamadhyamakakārikā; and Shantideva (8th century). Buddhapālita (470–550) has been understood as the originator of the 'prāsaṅgika' approach which is based on critiquing essentialism only through "reductio ad absurdum" arguments. He was criticized by Bhāvaviveka (c. 500 – c. 578), who argued for the use of syllogisms "to set one's own doctrinal stance". These two approaches were later termed the Prāsaṅgika and the Svātantrika approaches to Madhyamaka by Tibetan philosophers and commentators.