"Another unsettling element in modern art is that common symptom of immaturity, the dread of doing what has been done before"

In this quote, Edith Wharton is referring to a common trend in modern-day art where artists hesitate to produce something that has actually currently been done in the past. She describes this as a sign of immaturity, suggesting that these artists do not have the self-confidence and creativity to push borders and create something really special. This worry of repeating can be seen as a hindrance to the development and evolution of art, as it limits the potential for new and ingenious ideas. Wharton's use of the word "unsettling" also implies a sense of discomfort or anxiousness with this pattern in modern art, perhaps hinting at her own individual viewpoint on the matter.