What does the phrase "the abnormal mind" mean in this excerpt from the first chapter of The Great Gatsby?
"In consequence I'm inclined to reserve all judgments, a habit that has opened up many curious natures to me and also made me the victim of not a few veteran bores. The abnormal mind is quick to detect and attach itself to this quality when it appears in a normal person, and so it came about that in college I was unjustly accused of being a politician, because I was privy to the secret griefs of wild, unknown men."
In Chapter One, Nick Carraway wishes to establish himself as an objective narrator, claiming that he "reserve[s] all judgments." Because of his non-judgmental nature, he claims, he has found that many people are more likely to speak candidly to him, especially those of "curious natures" and those who are "abnormal," or unlike him. The word abnormal also suggests those who are unlike Nick in not having had the advantage of possessing "a sense of the fundamental decencies" because as Nick observes, this sense is "parcelled out" unequally when one is born. Further, Nick describes the confidences given him from "abnormal minds":
Most of the confidences were unsought--...for the intimate revelations of young men or at least the terms in which they express them are usually plagiaristic and marred by obvious suppressions.
With this introduction to himself as narrator, Nick establishes his reliability because he is normal and has had a fortunate "parcelling" of the basic decencies of human nature. So, in contrast to the confidences of others, Nick's narration is at a "moral attention"; Nick contends that unlike "abnormal" people, he is trustworthy.