Brahmajalasutta 3.50

3.50.1

Tatra, bhikkhave, ye te samaṇabrāhmaṇā pubbantakappikā pubbantānudiṭṭhino pubbantaṃ ārabbha anekavihitāni adhimuttipadāni abhivadanti aṭṭhārasahi vatthūhi, tadapi phassapaccayā.

they speculate and theorize about the first beginning on these eighteen grounds …