- The laws of nature
In addition to his work as a dramatist, Seneca was a Stoic philosopher. The Stoics believed that reason and the laws of nature must always govern human behavior. In making the conscious choice to pursue her sinful passion for her stepson, Phaedra disturbs the laws of nature to such a degree that, according to Seneca’s Stoic ideology, only her death can restore the cosmic order. Likewise, Hippolytus feels that Phaedra’s lust has tainted him, and he does not wish to live in a world that is no longer governed by moral law. It should be noted, however, that Hippolytus does not himself represent Stoic ideals. He denies ordinary human social bonds and isolates himself from society, thus making his moral existence unstable, especially in the face of his stepmother’s unnatural advances.
- Animal imagery and hunting
The opening scene of Phaedra shows Hippolytus with his men preparing for the hunt. According to scholar Alin Mocanu, Seneca chooses to describe their preparations with vocabulary, "that would be appropriate both to a hunt for animals and to an erotic hunt." Later in the play, Hippolytus transitions from hunter to prey, as Phaedra becomes the predator in the pursuit of her stepson. Both Phaedra and her nurse describe Hippolytus as if he were a wild animal, referring to him as "young beast" and "ferocious". Phaedra, in turn, refers to herself as a hunter: "My joy is to follow in pursuit of the startled beasts and with soft hand to hurl stiff javelins." The centrality of hunting to the plot is, furthermore, demonstrated by the fact that Diana, the goddess of the hunt, is the only deity who has an altar on stage, and the altar is important enough to be referenced four times in the course of the play.
Stepmothers and mothers
In Phaedra, Seneca addresses the pervasive Roman stereotype of the amoral and wicked stepmother. Phaedra is referred to as a stepmother four times throughout the course of the play, each time at a moment of climactic action. This is notable when compared to Euripides’ Hippolytus, in which the word stepmother is never used to describe Phaedra. According to scholar Mairead McAuley, "Roman obsession with both wicked and sexually predatory stepmother figures indicates a prevailing belief that the stepmaternal role led inherently to feminine lack of control and destructive impulses." It is important to note, however, that Seneca does not represent Phaedra as merely a caricature of the evil stepmother, but paints her in a more sympathetic light by showing her inner conflict and turmoil.
Phaedra believes that her unnatural feelings for Hippolytus can be traced back to the transgressions of her own mother, Pasiphaë, who mated with a bull and gave birth to the Minotaur. Phaedra says, "I recognize my wretched mother’s fatal cures; her love and mine know how to sin in forest depths." The Nurse, however, points out that Phaedra’s crime would be even worse, because Phaedra is self-aware and not a victim of fate. The Nurse says, "Why heap fresh infamy upon thy house and outsin thy mother? Impious sin is worse than monstrous passion; for monstrous love thou mayest impute to fate, but crime, to character." In the end, Phaedra can be seen to meet a fate similar to that of her mother, for her unnatural lust brings about the creation of the monstrous bull that dismembers Hippolytus.