Note the interplay between Decoud and Antonia in this paragraph of general disillusionment.
Antonia's lips are "firmly closed" -- the spokeswoman of idealism is
significantly silent amid the doubts. Behind the screen of her fan (her dream-ideal),
she has "averted her head" from Don Jose to gaze at Decoud, signalling
a transfer of her loyalties. Decoud, however, has lapsed into "a scornful
and complete detachment," i.e., full skepticism, explicitly ignoring her
look.