Towards the end of the book you may find this part, which explains basically why Holden Caulfield is not right denying the whole world around him and gives the reader together with Holden’s sister only moral support agains the self-destroying attitude of the main character.

…

He went over to this desk on the other side of the room, and without sitting down wrote something on a piece of paper. Then he came back and sat down with the paper in his hand. “Oddly enough, this wasn’t written by a practicing poet. It was written by a psychoanalyst named Wilhelm Stekel. Here’s what he-Are you still with me?”

“Yes, sure I am.”

“Here’s what he said: “The mark of the immature man is that he wants to die nobly for a cause, while the mark of the mature man is that he wants to live humbly for one.’”

…

You could tell he wasn’t tired at all, though. He was pretty oiled up, for one thing. “I think that one of these days,” he said, “you’re going to have to find out where you want to go. And then you’ve got to start going there. But immediately. You can’t afford to lose a minute. Not you.”

I nodded, because he was looking right at me and all, but I wasn’t too sure what he was talking about. I was pretty sure I knew, but I wasn’t too positive at the time. I was too damn tired.

…

Once you get past all he Mr. Vinsons, you’re going to start getting closer and closer–that is, if you want to, and if you look for it and wait for it–to the kind of information that will be very, very dear to your heart. Among other things, you’ll find that you’re not the first person who was ever confused and frightened and even sickened by human behaviour.

(The rest of Mr. Antolini’s thoughts regard the fact the scholarly men can express themselves better and clearer and are much much more humble. He also went on about finding out the size of one’s mind during the studies, knowing precisely how much and what fits in. Also he mentions that scholarly men, when brilliant and creative to begin with (which is rarely the case), tend to simply leave more records behind them. So they contribute more and let others learn from them.)