A frequent trope of many Restoration and 18th-century works is the exchanging of letters, which often contain proof of scandal or innocence. In The Conscious Lovers, letters exchanged potentially inappropriately or illicitly between people who should not be communicating represent the dangers of secrecy and play into the theme of Honesty and Integrity in Relationships. When Bevil Jr. and Lucinda correspond secretly about their decision not to marry one another, Myrtle assumes that these letters contain the “scandal” of Lucinda and Bevil Jr.’s love. Myrtle is confused and upset by any private correspondence between his beloved Lucinda and another man, but he cannot address the issue with Lucinda. In response, Myrtle sends a letter of his own challenging Bevil Jr. to a duel. 

The implication of Myrtle’s strong reaction to learning about this correspondence is that the letters—smuggled into Lucinda’s home via secrecy-promoting servants—symbolize a sexual penetration of a private space. This interpretation of hidden letters as sublimated sexual contact is common in modern scholarship about 18th-century literature. In Act IV, Scene 1, the play’s climactic moment, Bevil Jr. breaks the secrecy of the letters to reveal his and Lucinda’s innocence.