"A central aspect of punishment by imprisonment is that most opportunities for diversion are denied the prisoner. And, there being few other means for protecting oneself against angst, prisoners are for the most part constantly on the brink of utter despair. Any measures he can find to stave off this despair are justified as an attempt to preserve life itself; for the moment he experiences his soul alone in the universe, there is nothing else to see but the categorical impossibility of existence."