 Like Greek atomism, Indian atomism was speculative and local. The roots of Indian atomism can be traced back to the Upaniṣadic doctrine of five elements (pañca-mahābhūtas), viz., earth, water, fire, air, and vyom or ākāśa. According to the Nyāya-Vaiśeṣika philosophers, the first four elements are of two types—eternal and non-eternal. Atoms are eternal, while composite ‘wholes’ are non-eternal, since every product is eventually destroyed. Atoms, it is claimed, possess the smallest magnitude (aṇu-parimāṇa), are spherical (parimaṇḍala), indivisible, and eternal. Though quantitatively identical, each type of atom has specific attribute. An earth atom has odour, a water atom taste, a fire atom colour and an air atom has touch as specific attribute. What motivates an atomistic conception of nature? Nyāya-Vaiśeṣika thinkers offer a two-step argument to establish the existence of atoms. The first step is: