Sunyata (Emptiness) — The Heart of Mahayana

Sunyata is the central philosophical insight of the Madhyamaka school founded by Nagarjuna, whose Mulamadhyamakakarika demonstrates through prasanga (reductio) that all dharmas are devoid of svabhava (inherent existence) precisely because they arise through pratityasamutpada — 'whatever is dependently originated, that we declare to be sunyata' (MMK 24.18). The Heart Sutra crystallizes this as the identity of the five skandhas with emptiness: 'iha Sariputra rupam sunyata, sunyataiva rupam.' Sunyata is not nihilism (ucchedavada) — Nagarjuna explicitly rejects this in MMK chapter 24, arguing that emptiness is the condition of possibility for all conventional designation (prajñapti), karmic causation, and the entire Buddhist path. Chandrakirti's Prasannapada commentary clarifies that sunyata is itself empty (sunyata-sunyata), preventing reification of emptiness into a new metaphysical ground.