Nagarjuna, thought to have lived in southern India in the second century, is Buddhism's most profound theorist and one of the sharpest logicians in the whole history of philosophy. He took the idea at the heart of the Buddha's teaching — "dependent origination," that every phenomenon arises in dependence on other conditions — to its logical conclusion.

His masterwork, the "Mūlamadhyamakakārikā" (Fundamental Verses of the Middle Way), pursues a single thesis with extraordinary rigour: nothing has *svabhāva* — an intrinsic, independent, unchanging essence of its own. A thing becomes "that thing" only in relation to other things; seek an essence apart from those relations and it is nowhere to be found. This Nagarjuna calls *śūnyatā* — "emptiness." It is not nothingness or non-existence; on the contrary, it names the interdependent, fluid, conditioned nature of everything.

His method is destructive: he does not prove a view but refutes every possible form of its opposite by driving it into internal contradiction (*prasaṅga*). Neither existence nor non-existence, neither permanence nor annihilation can be coherently maintained; thus the mind is freed from the illusion that concepts carry reality in themselves. Nagarjuna draws the famous distinction of the "two truths": the level of everyday, conventional truth and the level of ultimate truth. The two do not conflict; to grasp emptiness is not to deny the everyday world but to see it rightly.

This thought became the philosophical backbone of Mahayana Buddhism, shaping the Tibetan, Chinese, Korean, and Japanese Buddhist traditions for centuries. The paradoxical language of Zen and the relational worldview of East Asia draw largely from this root. On ground diametrically opposed to Western philosophy's search for "essence," Nagarjuna left the most systematic example of thinking reality not through essences but through relations.