The central theme of the play is the theme of Class Conflict and Social Hierarchy. In his Preface, Strindberg explains that his play tackles the social Darwinist idea that the old hereditary aristocracy is being replaced by a new aristocracy made up of hard-working people who originated in the lower classes: In Darwinist terms, Strindberg sees this as a conflict of the stronger against the weaker—indeed, as a conflict that will inevitably favor the stronger.

For Strindberg, each class has its own strengths and weaknesses. Strindberg thus characterizes the aristocratic Julie (and her family) as “a relic of the old warrior nobility now giving way to the nobility of nerve and intellect” (68). Many of the same qualities that once made the aristocracy powerful in Europe—their obsession with honor, for example—now become their weaknesses, and Strindberg points out that “[t]he slave’s advantage over the nobleman is that he lacks this fatal preoccupation with honor” (69).

Despite the possibility of social mobility, social climbing is not easy in the world of Strindberg’s play. Jean’s dream (which he relates to Julie) sums up the challenges of upward mobility in symbolic terms: Jean longs to climb a tall tree to raid the golden eggs from a bird’s nest, “but the trunk’s so thick and smooth, and it’s so far to the first branch” (84).