This document discusses the concept of Abhava or non-existence according to various schools of Indian philosophy including Nyaya and Vaisheshika. It defines Abhava as that which depends on its opponent for knowledge and whose existence is negation. There are several types of Abhava including Sansargabhava (temporary non-existence), Pragabhava (non-existence prior to production), Pradhvansabhava (non-existence after destruction), Atyantabhava (absolute and eternal non-existence of one thing in another), and Anyonyabhava (mutual exclusion between two different things). Ayurveda also recognizes Abhava in terms of the absence of disease