Postmodernism is a cultural movement that developed as reaction to Modernism in 60s. While Modernism was still concerned with metaphysical reality and it still believed to find a truth, Postmodernism gives up the quest. An important element in Postmodernism is globalization, that was speeded up by the advent of technologies. Globalization makes different cultures easy to access and to mixture. For example there is not anymore distinction between low art and high art.
The Hours is structured around three women living in different periods. The narration does not follow a chronological order, indeed, the three women's stories alternate.
Michael Cunningham did not adopt a chronological sequence because in Postmodernism time can not be conceived in terms of linear chronology, indeed, people do not perceive time in a linear way. The story is one day-limited because it is more important to enter in the character's conscience using streams of consciousness and interior monologues.

Modernist man had not points of reference: God's existence was put into question, progress did not produce well-being and the vision of time and space was revolutionized. However he believed to be able to find a new centre and a new truth with reason. Postmodernism is against this vision. Therefore reason can not lead through knowledge and it can not lead to truth. Language is the only tool that human beings have got. Nevertheless reason is used in communication as a weapon in order to attack the powerless.