Philosophical notes
Although it is not explicitly identified as such by Rand, the contents of this page of philosophical notes suggest that it may have been related to Roark’s speech at the end of the novel contrasting first-handers (individualism) and second-handers (collectivism).
One point of interest is the note near the top about the importance of individual judgment; regardless of one’s level of intelligence or ability, one can still be independent in judgment, whether of works of art or anything else.