I'd like to know if in this extract of The Great Gatsby (chapter 4) "nice" has its average meaning (beautiful, good) or if it is a modifier or an intensifier of "durable" such as in the sentences "a nice cold drink", "to have a nice long nap", "nice and warm", where "nice" means "really"?
A stout, middle-aged man with enormous owl-eyed spectacles was sitting somewhat drunk on the edge of a great table, staring with unsteady concentration at the shelves of books. As we entered he wheeled excitedly around and examined Jordan from head to foot.
“What do you think?” he demanded impetuously.
He waved his hand toward the book-shelves.
“About that. As a matter of fact you needn’t bother to ascertain. I ascertained. They’re real.”
“Absolutely real—have pages and everything. I thought they’d be a nice durable cardboard. Matter of fact they’re absolutely real. Pages and—Here! Lemme show you.”
This is an interesting question. The man who has been examining Gatsby's books is given owl-eyed spectacles in order to characterize him as somebody who does a lot of reading, knows a lot about books, and is probably a professor. When he says he thought they would be made of cardboard, he means, of course, that he thought they would all be complete fakes without any printing inside or even any pages. He is being ironic when he says he thought they would be "a nice durable cardboard." He means he expected them to be fakes but that he expected them to be good-quality fakes. Evidently he is not only knowledgeable about books but about fake books, and he knows the difference between good fakes and cheap fakes. One of the characteristics of good fakes would be that they would be "durable."
So the inebriated guest is indirectly expressing an opinion of Gatsby himself. He thinks Gatsby is like a lot of nouveau riche who are trying to make an impression in order to move up into a higher level of society. This is actually the case, but what impresses the man in the owl-eyed spectacles is that Gatsby is doing such a complete job of it. The man evidently has known "bounders" and "arrivistes" who built mansions, hired servants, and even bought old framed oil portraits to pass off as ancestors, but who filled their library shelves with cheap-quality fake books because they couldn't tell the "nice" difference between good fakes and cheap fakes and would never think it necessary to go to the expense of buying a whole library full of real leather-bound, deckle-edge classics. They wouldn't think it necessary to buy real books because they weren't educated themselves. They hadn't been to good schools, like the real aristocrats. They didn't read classics and didn't expect any of their guests to take an interest in stodgy old authors like Montaigne, Voltaire, Carlyle, Plutarch, or any of the other names that lined their shelves.
When the book expert says he thought the volumes would be nice durable cardboard, he is plainly insulting Gatsby, implying that he is an impostor, a phony--but a very good phony. Fitzgerald's whole novel is about a man trying to break into high society because of his fantasy about a female airhead member of the upper class. The word "nice" as applied to the cardboard books the expert expected Gatsby to have on his shelves has invidious connotations. He is crediting Gatsby with being a very conscientious, unstinting, and cunning pretender but a pretender nevertheless. "Nice durable cardboard" means superior quality fake.
The reader does not feel the contempt for Gatsby that is felt by the book expert or by Tom Buchanan. The reader feels pity for this rather naive outsider who is figuratively beating against a door that will never open. Fitzgerald is writing about himself in The Great Gatsby. He went to an Ivy League college and fraternized with the playboy sons of the country's moguls, but he never felt that he was part of their world; and he killed himself trying to prove he was as good as they were, when in reality, like Gatsby, he was a whole lot better.