Nāgārjuna develops in the Mūlamadhyamakakārikā (c. 150 CE) the catuṣkoṭi, or tetralemma: a logical system of four mutually exclusive positions for any proposition — (1) it is A, (2) it is not A, (3) it is both A and not-A, (4) it is neither A nor not-A. This system violates the Aristotelian principle of non-contradiction by allowing a proposition and its negation to be simultaneously true (position 3), without the system collapsing into triviality. The philosophical motivation is śūnyatā (emptiness): no entity has intrinsic existence, everything exists in relational dependence, which makes binary categories insufficient to describe reality. The catuṣkoṭi is the first documented logical system that tolerates contradiction without logical explosion. The logician Graham Priest explicitly cites it as a historical precursor of paraconsistent logic in In Contradiction (1987). Its transmission into the Western logical canon arrived 1,800 years late.