Vajrasuci (Siddhacarya Ghoshapada) 22

22

(bha) ato'sya vacanasya70 prāmāṇyādaniyato'yaṃ brāhmaṇaprasaṅgaḥ
(ma) kiṃ cānyat| śūdro'pi brāhmaṇo bhavati| ko hetuḥ? iha hi
mānave dharme'bhihitam71—
araṇī72garbhasambhūtaḥ kaṭho73 nāma mahāmuniḥ
tapasā brāhmaṇo jātastasmājjātirakāraṇam

(bha) Therefore, on the authority of this statement, this matter of being a brāhmaṇa is variable.
(ma) Furthermore, what else? Even a śūdra becomes a brāhmaṇa. What is the reason? For here in the Law of Manu it is declared:
The great sage named Kaṭha was born from the belly of a fire-drill;
he became a brāhmaṇa through austerity; therefore, birth is no cause.