How we cite our quotes: (Chapter.Paragraph)
Quote #4
The taste of the usual was like cinders in his mouth, and there were moments when he felt as if he were being buried alive under his future. (15.60)
The "usual" is felt to be a kind of horrible death, killing off everything that's lively and passionate and spontaneous. Also, cinders taste terrible.
Quote #5
The silence that followed lay on them with the weight of things final and irrevocable. It seemed to Archer to be crushing him down like his own grave-stone; in all the wide future he saw nothing that would ever lift that load from his heart. (18.79)
Yet another instance where Archer sees his future as a slow process of dying. A fun thing to do would be to use this quote in a graduation speech. Just kidding: that would be the least fun thing in the world.
Quote #6
The things that had filled his days seemed now like a nursery parody of life, or like the wrangles of medieval schoolmen over metaphysical terms that nobody ever understood […] Yet there was a time when Archer had had definite and rather aggressive opinions on all such problems, and when everything concerning the manners and customs of his little tribe had seemed to him fraught with world-wide significance. (19.14)
Archer's passion for Madame Olenska is the only thing he feels is "real." Everything else seems artificial and ridiculous. We get it. What kind of silverware you set out for dinner is a pretty dull preoccupation.