Sunyata is not a peripheral Buddhist idea but arguably the central technical commitment separating Madhyamaka from other Buddhist schools and from every non-Buddhist system that posits a fixed underlying reality, which is precisely why it draws fire from more directions than almost any other position in this atlas. Essentialist and realist philosophies in the Western tradition, which hold that natural kinds have real defining essences, reject emptiness as incoherent, arguing that dependent origination itself, the process by which things arise, presupposes something that does the arising with a stable identity across the process. Vedantic monists press a different objection, arguing that Madhyamaka's total rejection of any fixed ground, even a non-dual Brahman, leaves it unable to explain what, if anything, is finally liberated, a criticism Madhyamaka answers by denying that liberation requires positing any such fixed ground at all.
Within Buddhism itself, Yogacara philosophers, while accepting emptiness, argued Madhyamaka's presentation left the status of consciousness itself dangerously underspecified, prompting centuries of internal debate over how radically the doctrine of no-self, anatta, should be pushed once emptiness is taken all the way down.