According to Ishmael, what is the only way we will change our behavior?

"He was like me--he just yearned for there to be someone in the world like Leo, someone with a secret knowledge and a wisdom beyond his own. In fact, of course, there is no secret knowledge; no one knows anything that can't be found on a shelf in the public library. But I didn't know that then"

Early on, the narrator grows indignant at Ishmael's ad, since it reminds him of earlier disappointments. In his teenage years, the narrator sought a teacher who could tell him what was wrong with the world. He felt that he was being lied to about something, but could never articulate what that lie was.

As we discover both in this passage and through the novel, the frustration comes from the difficulty, and not the desire. In fact, much of what Ishmael teaches the narrator involves knowledge he already has - what is new is the way Ishmael arranges that information, the new perspective on it that he presents. So what is most frustrating to the narrator (in the passage above) is that he senses he has all the tools to discover this on his own, but lacks a system by which to properly use those tools.

Quinn uses this device to alert readers to the fact that everyone has the ability to change the world; it does not depend on finding new information or wisdom. It depends on evaluating the status quo, and rethinking the way that society is currently living.