"Hi, how are ya," some people say when they see a familiar face. The words run together into a mass, all sense and meaning lost. All the same, people do care how you are. After they greet you, it's likely you will greet them back, with an equally meaningless phrase like, "Can't complain, can't complain. " You could probably complain, at length, or share a brilliant thought you were just beginning when a greeting interrupted you. You don't though, you say, "Great, you?"
You are not giving each other information about your health and well—being. All the same, you are sharing information. You're acknowledging each other's positions as acknowledged friends, or at least as accepted acquaintances. And you are reestablishing the ties that may have lapsed since yesterday.
It's what anthropologist Bronislaw Malinoski called a phatic communication. Its message is not in the words you use, but in the fact that you speak ritually accepted words. In Asia, for example, people may ask one another if they have eaten, or if they are busy. They're not really asking for their lunch menu or their agenda, they are saying hello. A phatic signal says hi.
There's embarrassment of being near people without acknowledging them. That uncomfortable feeling is one reason why lonely passengers in the subway may behave as if they cannot see anyone around them or may escape their uncomfortable situation with a book. Some people read all the way home, and never turn a page.
Your friend isn't asking how you are, and you aren't telling him. However, he is recognizing your existence, and when you answer, you are recognizing his. In addition, the set speech you have shared opens the door to closer communications if both agree. Someday, you may come to real close friendship, and really tell one another how you are.
Meanwhile, people who greet one another this way do care. They care enough to recognize someone's essential humanity. They send a signal across the space between, to share, very briefly and lightly, in awareness of one another.
Your greetings prove that neither of you has become a social outcast. How are you? You are still a member of society in good status. You are still the one who knows the rituals necessary to get to work each day.