| Quote #1
Ivan Ilych felt himself abandoned by everyone, and that they regarded his position with a salary of 3,500 rubles as quite normal and even fortunate. He alone knew that with the consciousness of the injustices done him, with his wife's incessant nagging, and with the debts he had contracted by living beyond his means, his position was far from normal. (3.2)
This is the first and only time Ivan Ilych experiences a sense of isolation before his sickness. And it's for a silly reason – nobody's willing to give him money to cover the debts he's racked up by living beyond his means. No one else seems to think having a salary of 3,500 rubles and not getting the promotion he wanted is terribly tragic. It's like Ivan feels isolated from everything whenever his life isn't what he wants it to be.
| Quote #2
And it seemed to him that the meaning of what the doctor had said was that it was very bad. Everything in the streets seemed depressing. The cabmen, the houses, the passers-by, and the shops, were dismal. His ache, this dull gnawing ache that never ceased for a moment, seemed to have acquired a new and more serious significance from the doctor's dubious remarks. Ivan Ilych now watched it with a new and oppressive feeling. (4.9)
Ivan just had his first meeting with a doctor. The exam is inconclusive, but this doesn't prevent Ivan from getting nervous. And look at what effect his fear has. Ivan is normally cheerful, yet now everything around him seems bleak and depressing. It's just going on as usual, while he might be facing the end. The world at large isn't concerned with him and can't help him anyway. Ivan's fear is beginning to cut him off from the normal world around him.
| Quote #3
There was no deceiving himself: something terrible, new, and more important than anything before in his life, was taking place within him of which he alone was aware. Those about him did not understand or would not understand it, but thought everything in the world was going on as usual. That tormented Ivan Ilych more than anything. He saw that his household, especially his wife and daughter who were in a perfect whirl of visiting, did not understand anything of it and were annoyed that he was so depressed and so exacting, as if he were to blame for it. (4.17)
Now Ivan starts to experience the strong sense of isolation from other people that will only grow as his disease worsens. To him it seems like no one else sees or cares about what he's experiencing. In particular, he seems to get no help from his family. To Ivan, what's happening is the most important and terrifying thing in his life. His wife and daughter are happy to just keep shopping.