Critics agree that the most important stylistic element of Joyce's novel is structure. Joyce deliberately attempted to create a new style of novel by rejecting the convention of plot.
Instead of a conventional plot--an orderly chronologically oriented element developed over time in the English language novel beginning with Defoe's Robinson Crusoe--Joyce chose a structure built upon vignettes of pivotal times in Stephen Dedalus's life. These vignettes show the picture of Stephen's develop into an artist writer.
So while Stephen faces conflicts, like his conflict with his parents' Catholicism and with the Catholic Church, there is no contiguous plot development of the conflict through climax and resolution. It is Joyces's new structure, including his new way of structuring dialogue and a narrator whose voice accommodates the various age levels of Stephen's development, that makes this an important novel in the development of Modernism in literature.
[Cranly] turned towards his friend's face and saw there a raw smile which some force of will strove to make finely significant.
Cranly asked suddenly in a plain sensible tone:
—Tell me the truth. Were you at all shocked by what I said?
—Somewhat, Stephen said.
—And why were you shocked, Cranly pressed on in the same tone, if you feel sure that our religion is false and that Jesus was not the son of God?
—I am not at all sure of it, Stephen said. He is more like a son of God than a son of Mary.