But the possibility of a “first cause at some point” seems to be ruled out by what follows in the Avijjāsutta:
‘A first point of ignorance, bhikkhus, is not discerned (na paññāyati) such that before this there was no ignorance and afterward it came into being.’ Still, ignorance is seen to have a specific condition.
“I say, bhikkhus, that ignorance has a nutriment; it is not without nutriment… etc.
So it seems to me (pace Javier) that the na paññāyati (“is not discerned”) here is not just epistemological. It’s as ontologically pregnant as the na paññāyati of, say, the Hatthapādopamasutta:
“When, bhikkhus, there are no hands, picking up and putting down are not discerned (na paññāyati). When there are no feet, coming and going are not discerned (ibid.). When there are no limbs, bending and stretching are not discerned (ibid.). When there is no belly, hunger and thirst are not discerned (ibid.).”
An absence of hands means that there isn’t any picking up and putting down. It doesn’t mean merely that picking up and putting down can’t be seen happening (but might nonetheless be happening in a manner that no one has the epistemic nous to discern).