Vaisesika Sūtra 1.1.3

तद्वचनादाम्नायस्य प्रामाण्यम् ॥३॥

tad-vacanād-āmnāyasya prāmāṇyam ॥3॥

[तद्-वचनात् (tad-vacanāt) - because of that statement; आम्नायस्य (āmnāyasya) - of the Veda (sacred tradition); प्रामाण्यम् (prāmāṇyam) - authority, validity;]

That, i.e. DHARMA, is deciphered from scriptural statements that are 'pramanas', i.e. valid source of knowledge.