The Sisters is Irish writer-James Joyce's first short story starting to announce and criticize Dublin social problems-high religious stress and spiritual paralysis.This paper analyzes conversations between the characters.It is discovered that these conversations violate the Cooperative Principle proposed by Paul Grice-unwilling blank with disability,helpless taboo with numbness and no opinioned blindness.Joyce arranges this kind of "illogical" conversation to announce thought regression,moral code paralysis and blind religious belief,thus deepens the theme in the novel-spiritual paralysis.