I also like that in Buddha-Dhamma ignorance is not only about true knowledge (having a certain knowledge) but especially about how that knowledge has really ended defilements (anusaya, asava, tanha, kilesa). So it also refers to a fruit, a result. From MN36:
…"But as to how to define whether someone is deluded or not, listen and pay close attention, I will speak.”
“Yes, sir,” replied Saccaka.
The Buddha said this:
“Whoever has not given up the defilements (i belief here is refered to asava’s, Green)corruptions that lead to future lives and are hurtful, resulting in suffering and future rebirth, old age, and death—is deluded, I say. For it’s not giving up the defilements that makes you deluded. Whoever has given up the defilements—corruptions that lead to future lives and are hurtful, resulting in suffering and future rebirth, old age, and death—is not deluded, I say. For it’s giving up the defilements that makes you not deluded.
The Realized One has given up the defilements—corruptions that lead to future lives and are hurtful, resulting in suffering and future rebirth, old age, and death.
In that sense, it seems impossible that one cannot be not-ignorant or not-deluded with defilements still arising in the mind. So in that sense a measure for avijja can be…is there or is there not still defilement?
I also think avijja is gradual, like hate and greed. It gradually weakens. Some say moha is the strongest form of avijja and is not present anymore in a Sotapanna, but i have not seen this in the EBT.
One might have very much knowledge, wordly, intellectually, intuition, gnosis, mystic, but it seems the Buddha teaches that one is still deluded as long as defilements are not really uprooted.
So in that sense the measure of ignorance can be the degree of defilement. Only an arahant has really overcome the avijja-anusaya.
Is stream-entrance the end of ignorance? If measured against the above i do not think so. There are still a lot of defilements. Is the opening of the Dhamma-eye the end of ignorance?
What is the counterpart of ignorance?”