Prison is anything that severs and alienates... paradise is the reclaiming commons with the fences thrown down.
Prison is nothing but job insurance for the courts and the police, offering the illusion that they are effective.
Prison is essentially a highly palpable shortage of space made up for by an equally palatable surplus of time.
Prison is, in America, such that all emphasis is on punishment, retribution, and disparagement, and almost none is on rehabilitation.
Prison is a (new) way of acting on bodies that entirely different from penal law. It is concerned with visibility (i.e. Surveillance, or the management of new objects such as the masses or population).
Prison is a way of pretending to solve the problem of crime. It does nothing for the victims of crime, but perpetuates the idea of retribution, thus maintaining the endless cycle of violence in our culture.
Prison is not meant to eliminate criminal behavior, since it is obvious that they produce recidivism and criminal subcultures. Instead, they distinguish, divide, and distribute illegalities, thereby differentiating them in various manageable forms.