About Catuṣkoṭi

Catuṣkoṭi is a logical argument(s) of a 'suite of four discrete functions' or 'an indivisible quaternity' that has multiple applications and has been important in the Dharmic traditions of Indian logic, the Buddhist logico-epistemological traditions, particularly those of the Madhyamaka school, and in the skeptical Greek philosophy of Pyrrhonism.
Nāgārjuna (right) and Āryadeva (middle).

Madhyamaka – Buddhist philosophy and practices

Madhyamaka also known as Śūnyavāda and Niḥsvabhāvavāda refers to a tradition of Buddhist philosophy and practice founded by the Indian philosopher Nāgārjuna. The foundational text of the Mādhyamaka tradition is Nāgārjuna's Mūlamadhyamakakārikā. More broadly, Madhyamaka also refers to the ultimate nature of phenomena and the realization of this in meditative equipoise. According to the classical madhyamaka thinkers, all phenomena () are empty (śūnya) of "nature," a "substance" or "" (svabhāva) which gives them "solid and .