In Émile Zola's essay on naturalism and theater, he takes umbrage with the artificial elements of plays and performances. Zola expresses contempt for the "contrived formulas, the tears, and the superficial laughs." He seems to be tired of lofty, pretentious dialogue. He speaks out against "majestic speech and noble sentiments."
What Zola wants is a theater that is based in reality. Zola seems to be advocating for a more human approach to theater. By getting rid of all the pomp and ceremony, the theater can teach audience members a "frightening lesson” about humans and their various predicaments.
Now it's time to compare Zola's attitudes to the theater to how the theater is portrayed in the first chapter of his novel Nana.
What sticks out to me is how the play contrasts with the actresses. The play—The Blonde Venus—doesn't seem to correspond with Zola's thoughts on the theater. If Zola wanted the theater to focus on nitty-gritty humanity, he probably shouldn't have included a play about goddesses.
Yet the actresses who play the goddesses seem to bring the humanity that Zola longs for. Diana is played by Rose. Zola describes Rose as possessing "neither the face nor the figure for the part." She’s ugly—an adorable kind of ugly, but ugly nonetheless.
Then there's Nana. Nana, of course, plays Venus. When she comes onto the stage, the audience laughs.
In a way, you could argue that both Nana and Rose help Zola achieve his goal of making the theater more humane and less artificial. You could tell how the imperfect humanness of Rose and Nana infects their respective roles, which makes the goddesses less lofty and superficial and much more human.