It was the ability to continue doing the specific thing she was doing — inventing — in the face of adversity, without letting the adversity define the activity or end it.

Persistence of this kind requires a specific relationship with one’s own judgment.

You have to believe, in the absence of external validation, that the work is worth doing and that the ideas are good.

You have to maintain, against the pressure of rejection and delay and the ordinary exhaustion of daily life, the conviction that the problem you have identified is real and that your solution to it is sound.

This is not a simple thing.