To say "This book is about justice" is simultaneously right and wrong. It is right because it is technically true: this book literally is about justice. But still, the sentence lacks something essential, because Rawls intentionally elaborates a full, exhaustive definition of what justice is and what it looks like, and how it is accomplished. Truly, the book is really more about people than it is about people, and Rawls opinion of justice is that people have to learn empathy by way of justice.
By understanding that all people should be treated as ontologically equal, socially equal, and equally valuable in the public, Rawls begins to show that equality is actually a kind of gateway or portal into new ways of life. Instead of being in a society where everyone is asleep to justice, instead of just going around getting what they want from others all the times, like social consumers, perhaps, says Rawls, we can begin to build a new society where empathy is the standard, and where true justice is celebrated in the zeitgeist.
The zeitgeist is the unspoken third term of his arguments, because as he says, the correct domain to practice justice is in your personal life, but Rawls also knows that just people spread justice like an infection. By bringing new, more positive, affirming energy to one's relationships to loved ones and strangers, Rawls feels that justice can begin to manifest itself at the social level.
