योऽवमन्येत ते मूले हेतुशास्त्राश्रयाद्द्विजः ।
स साधुभिर्बहिष्कार्यो नास्तिको वेदनिन्दकः ॥
yo’vamanyeta te mūle hetu-śāstrāśrayād dvijaḥ |
sa sādhubhir bahiṣkāryo nāstiko veda-nindakaḥ ||
(Manu Smṛti: 2.11)
“A twice-born who disregards those two sources [of instruction, i.e., the Śruti and Smṛti] on account of adherence to hetu-śāstra [i.e., nyāya-śāstra] is an unbeliever (nāstika), a defamer of the Veda, and to be shunned by sādhus.”