pradīpaḥ sarva-vidyānām upāyaḥ sarva-karmaṇām
pradīpaḥ sarva-vidyānām upāyaḥ sarva-karmaṇām |
āśrayaḥ sarva-dharmānāṁ vidyoddeśe prakīrtitā ||
(Vātsyāyana’s Nyāya-bhāṣya on Gautama’s Nyāya-sūtra: 1.1.1)
“Ānvīkṣikī [i.e., logic (nyāya)] is stated in the enumeration of sciences [i.e., fields of knowledge] to be the lamp of all sciences (vidyās), the means for [accomplishing] all karmas, and the basis of all dharmas.”