I must admit, that opening line did very little for me. Neither did the rest of the book.
The main character gives his (and Joyce's?) theory of art: art should not create any response in the viewer. If it does, it mars the purity of the art. Joyce may be a great author; he certainly succeeded in writing a book that created no response whatsoever in me (other than annoyance at the time I wasted plowing through the tedium of something that I didn't care about whatsoever). That may be great art, but I don't have to like it.