In chapters 3 &4 of anthem

Equality believes is brothers are not happy because they are afraid. They cannot speak their minds, and they can never be certain that what they say is a collective belief. Thus, they are silent, frightened, and unfulfilled.

Yet our brothers are not like us. All is not well with our brothers. There are Fraternity 2-5503, a quiet boy with wise, kind eyes, who cry suddenly, without reason, in the midst of day or night, and their body shakes with sobs they cannot explain. There are Solidarity 9-6347, who are a bright youth, without fear in the day; but they scream in their sleep, and they scream: "Help us! Help us! Help us!" into the night, in a voice which chills our bones, but the Doctors cannot cure Solidarity 9-6347.

And as we all undress at night, in the dim light of the candles, our brothers are silent, for they dare not speak the thoughts of their minds. For all must agree with all, and they cannot know if their thoughts are the thoughts of all, and so they fear to speak.