Anne Cunningham points us towards a discussion of the realist novel:
In this inclusiveness, the realist novel never ceases to make allegorical (or functional) use of subordinate characters, but it does ferociously problematize such allegory, by more clearly and insistently putting it in juxtaposition with reference. Allegorical characterization now comes at a price: the price of the human particularity that it elides. In other words, the realist novel systematically reconfigures its own allegorical reduction of characters through a pervasive awareness of the distributional matrix.
Got that? I just love the final sentence, about which Anne has a pertinent observation.