Didion thinks that knowing morality is impossible.
It’s hard to know if she means “ethics.” – most do.
I have posted extensively about this in the past. Here too. And here.
The philosophical connection gives me pause though.
I mean, a strong society that has no means to differentiate between “good” and “evil” exists on the edge of function, without even knowing it.
The long and short of it is that you simply can’t live the day-to-day of your life in this manner. Laws, institutions, and all interactions are in the same boat.
If there is no line, well then, that’s just your opinion – and anything is permissible.
You see I want to be quite obstinate about insisting that we have no way of knowing—beyond that fundamental loyalty to the social code—what is “right” and what is “wrong,” what is “good” and what “evil.” I dwell so upon this because the most disturbing aspect of “morality” seems to me to be the frequency with which the word now appears; in the press, on television, in the most perfunctory kinds of conversation.
-Joan Didion, Slouching Towards Bethlehem