In the struggle between emotion and reason in Arcadia, Hannah Jarvis acts as the voice of reason. Hannah is the academic, feminist researcher who prides herself on thorough and well-thought research and sacrifices human contact for it. Hannah, like Thomasina's description of Queen Elizabeth, is able to separate sex from intellectual power and, in her case, push sex from view. Hannah resists carnal knowledge with effort: she doesn't like the idea of having her picture taken or submitting to a kiss, she refuses Valentine's idea of calling her his fiancée, and she scorns Gus's flirtation. Most of all, Hannah rejects Bernard's proposal that Lord Byron would have been silly enough to kill someone out of love.

It seems that Hannah did, at one point, know love but has decided to pursue better things ("I don't know a worse bargain. Available sex against not being allowed to fart in bed"). Hannah's rejection of love or knowledge of love has left her unaware of her own self. It appears as though she has deluded herself into academic sterility. Bernard tells Hannah that, if she understood herself a little better, she wouldn't have written her first book about Caroline Lamb, a romantic "waffle." When Hannah storms into Bernard's lecture and interrupts his speech about Lord Byron killing someone for love, Chloe turns psychologist for Hannah and politely asks her if she has been deeply wounded in the past.

Hannah cannot, however, reject the love of the shy Gus. The mute boy and mystery of the modern Croom household is able to crack Hannah, he is able to get her to dance with her. Gus's genius qualities, much like Thomasina before him, make him not only mentally like the subject of Hannah's studies, but give him an intuitive sense of history. As a silent messenger and connection to the past of Sidley Park, Gus gives Hannah the apple Septimus will eat and whose leaf Thomasina will describe. Gus also dresses Augustus in Regency wear, finds the foundation for the destroyed outbuilding, reveals the identity of the Sidley Park Hermit and asks Hannah for a much needed dance and embrace. Hannah accepts Gus's invitation for unknown reasons, but possibly his relevance and help with her own research play into the mix and certainly a real need for carnal embrace.