 Problems about the possibility of motion, developed especially by the Buddhist Nāgārjuna (2nd c. CE), prompted responses in other schools of thought (Matilal 1977, 79; Dasgupta 1987). Although the persistence of macroscopic bodies might be illusory, there were discussions about the momentum or persisting tendencies of moving bodies, the different directions exhibited by these tendencies in a rotating wheel, and the cohesion of particles within moving bodies.