Case study 2

So you take to walking. The walls begin to close in on you, so you flee them. You gain the empty streets. It is now that you notice a very curious effect, one which relates to your fellow humans. You begin to lose comprehension of them. Their movements and words and ideas begin to seem odd. You see them, of course, engaged on their various errands. You see people in cars, briefly glimpsed. You see couples arm in arm. You see groups of friends, gaily chatting, confident in numbers. You see the blue light of televisions in livingrooms, curtain-obscured, plant-shrouded.
But all they do and say seems impossibly remote from you, much more remote than, say, an animal could ever be. A dog will still deign to sniff you, a cat may flirtatiously rub itself against you. They recognise a fellow creature. But these awful, smug humans, with their hideous selfishness, their pathetic privacy. How they avoid your eyes. How they dwell  in illusion, how they artlessly construct and live in fantasy worlds. What can they possibly be thinking? What on earth are their motivations? You gaze at them as though you were behind a wall of glass, and they were all conversing eagerly in a totally foreign language.
Now, the former strange pauses, the feelings of something left undone, begin to expand and occupy more space. They combine with your forgetting of the language of social interaction, and well up at random moments. In the middle of the day, engaged in some commonplace task, washing up some dishes, say, you suddenly halt and struggle to get your bearings, as though lost.
Now is when the solitary man finds himself becoming odd. Sometimes on his nocturnal walks he murmurs to himself, or the interlocutor in his head. Often, now, he listens anxiously at night, trying to detect some texture in the silence, as though it was a blank stone wall that somehow bore a message. As though the silence were the pop and hiss of a needle on an ancient 45, and at any moment, some faint music would emerge. One night, the solitary man waits at a crossing for the light to change to green. It is midnight. He has walked up the long way from his empty flat through streets where seagulls fight over scraps. Suddenly, standing there, he says aloud "I am going mad".
Naturally, this frightens him very much.