The debate on ”existence”(sat) and ”non-existence,”(asat) including that on the ”non-self” (anātman) and ”self,”(ātman) has always been the major topic in Indian philosophy. It also marks, on a theoretical level, the difference between the orthodox and heterodox schools. The Buddhists hold to the view of ”non-self”; however, their denial of a ”self” and the Vedanta's view of ”nonexistence” do not mean the same; in fact there is a fundamental difference between the two. The debates on existence and nonexistence within the Buddhist schools refer to the question whether all things imply a foundational reality or not. According to the viewpoint of Japanese Critical Buddhism, those of the Buddhists who acknowledge the doctrine of tathāgatagarbha also endorse the existence of a ”self.” The present article discusses the internal Buddhist debates within the wider framework of Indian philosophy in order to find the traces and points of intersection where Buddhism and the schools of Brahmanism influenced each other.