Empirical 
<span>based on, concerned with, or verifiable by observation or experience rather than theory or pure logic.</span>
        
             
        
        
        
Key words would be the best :)
        
                    
             
        
        
        
An antecedent of a pronoun is a word that refers to the same thing as this pronoun. 
here the pronoun is "theirs"
<em>Rivers stopped flowing along the bank's so that they could hear Orpheus, whose music was harmonious than </em><em>theirs.</em>
 (all the words in Boldface refer to the same thing).
What does the "theirs" refer to? it refers to their music, and the they is the Rivers (it's a personification of rivers)
The antecedent is the river!
        
             
        
        
        
Could you elaborate a bit?
        
             
        
        
        
Answer: Gordimer´s political beliefs are reflected in this story in a way that she puts her view with the device os negatie dialects. For example: “art is the negative knowledge of the
actual world” (“Reconciliation Under Duress” ). Rather, art explores what is not known and
as Adorno explains, “art does not become knowledge with reference to mere immediate reality”
. Throughout her novels, Gordimer avoids references to the “immediate reality.” As Ettin
explains, we never get a full picture of the plot and instead the reader must orient himself by  considering what has not been said. As Gordimer draws on the theories of Adorno, she portrays  the strong appeal of this German, Jewish theorist, further distancing herself from the genre of
black authors and redefining the objective of a political novel.