Unlike modernist literature, postmodern literature was characterized by

a belief that meaning could be found.
dark humor and paranoid characters.
new techniques such as stream of consciousness.

 dark humor and paranoid characters" is correct.
 the easiest way to start thinking about postmodernism is by thinking about modernism, the movement from which postmodernism seems to grow or emerge. 
Like Jameson's characterization of postmodernism in terms of modes of production and technologies, the second facet, or definition, of postmodernism comes more from history and sociology than from literature or art history. 
hope it helps

To describe a new way of thinking that could be relied on