Extremely Loud and Incredibly Close is a post-9/11 reflective novel by Jonathan Safran Foer, concerning a young boy who tries to find meaning in the terrorist attacks and the loss of his father.
Throughout the book, Foer uses several stylistic techniques to show how Oscar, the protagonist, expresses his feelings. Because most of the book is written from Oscar's perspective, the blank pages that appear can have more than one meaning. The most obvious meaning is that laid out in the text:
I hit the space bar again and again and again. My life story was spaces. The days passed one at a time. And sometimes less than one at a time.
(Foer, Extremely Loud and Incredibly Close, Google Books)
Oscar's grandmother, feeling the loss of her husband (he deserted her) and her inability to connect with others, attempts to write her life story down, but cannot compose sentences; she uses blanks spaces, "writing with the space bar," to show her life and what it has meant. She feels that her life is just spaces separated by days and so there is little meaning to put on paper.
The other possible meaning is from Oscar's search; he has trouble reconciling his feelings with reality, and sometimes seems to feel nothing at all, so the blank pages could be a representation of his "blank" emotional state.
I think it means that Oscar doesn't find anything that he wants to say. I feel like he's done. The book is basically Oscar's diary and with blank pages it can mean,that he doesn't want to say anything. In the book, his grandmother tries to write her own story but she couldn't because she was at the "blank" emotional state and that it was like writing with a "space bar". Her life was bleak and there was nothing worth writing about. Oscar can't seem to word his feelings correctly and doesn't feel anything.