Vātsyāyana in his commentary (Bhāṣya) on the NS employs the word, nāstika and its derivatives, nāstikatva, and nāstikya, thrice (on NS, 1.1.1, 1.1.2 and 3.2.61, IIIb60 in Ruben). The meaning of nāstika (lit. negativist) in the last two instances is conventional and readily comprehensible. But it is not so evident in the case of the first. I propose to deal with this problem in detail and consider the views of other explicators of the NS.

Let us begin with NS, 1.1.2. In course of explaining what is meant by false knowledge (mithyājñāna), Vātsyāyana enumerates how evils produced under the influence of attraction and repulsion lead to moral lapses: “Driven by the evils and through the agency of the body one commits violence, theft and incest. Through words (one is led to) plotting against others, covetousness and nāstikya.” Vātsyāyana adds that motivations like these are sinful, resulting in adharma, lack of merit.

Apparently nāstikya is here associated with irreligiosity. The Manu very succinctly explains nāstika as ‘a defiler of the Veda’, nāstiko vedanindakaḥ (2.11). Defiling the Veda is one of the worst sins in the eye of Brahminical orthodoxy. By including nāstikya in the enumeration of vices, Vātsyāyana records his unflinching devotion to the Veda as well as his own orthodoxy.

It is, however, well known that the term, nāstika, is also employed by the Buddhists and Jains to designate those who, instead of denying the validity of the Veda, used to deny the existence of the other-world or after-life (paraloka) and hence the concept of virtue and vice.