 There are two contending theories of the natural world in India. According to the first, the empirical world arises out of combinations of atoms. Proponents of atomism (paramāṇuvāda) are found among Nyāya, Vaiśeṣika, Buddhist and Jaina thinkers. Sāṃkhya philosophers hold instead that the world is a transformation of an ever-dynamic Ur-Nature (mūla-prakṛti). Variations of this second conception are also available in some branches of Vedānta.