The introduction, by Claire Messud, quotes F. Scott Fitzgerald (pictured), as follows:
The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function. One should, for example, be able to see that things are hopeless and yet be determined to make them otherwise.
At any rate, it probably does take a first-rate intelligence to be able to function simultaneously in the two worlds I've identified, which define two different and rather opposed realities. Maybe that's why we're all having such a hard time doing it.