The doctrine of two truths distinguishes conventional truth, the world of persons and things as ordinarily described, from ultimate truth, their emptiness or the nature of reality. Nāgārjuna held that the ultimate cannot be taught without relying on the conventional. The schools differ widely on how the two relate.
Two truths
Conventional truth and ultimate truth: the Buddhist distinction between how things appear and how they are.
Also: samvriti and paramartha