In “Gaudy Night,” an essay about her detective fiction, Sayers said, “By choosing a plot that should exhibit intellectual integrity as the one great permanent value in an emotionally unstable world I should be saying the thing that, in a confused way, I had been wanting to say all my life.” To determine whether any of the dons might be responsible for the vandalism at Shrewsbury, Lord Peter engages them in a conversation on the subject of intellectual integrity and discovers that not one would sacrifice that quality for personal gain or emotional satisfaction. Lord Peter replies that “if it ever occurs to people to value the honour of the mind equally with the honour of the body, we shall get a social revolution of a quite unparalleled sort.” Further, as Sayers told Charles Williams, “I do not know whether we can be saved through the intellect, but I do know that I can be saved by nothing else.”
Annie Wilson acts as she does because she lacks that respect for intellectual integrity. Neither she nor her husband could understand why Helen De Vine would interfere with a man’s livelihood simply because he suppressed a piece of evidence. Driven by her emotions rather than by her reason, Annie is willing even to kill to get revenge.
Sayers does not reject emotion. At the end of the novel, Miss De Vine concedes that while she acted properly when she exposed Robinson, she was remiss in failing to alleviate the hardships her actions caused. Lord Peter and Harriet, too, recognize the need for a balance between head and heart. Shortly before Harriet accepts Lord Peter, they attend a performance of the Bach double violin concerto. Sayers chooses this piece intentionally, for it expresses the kind of life Lord Peter and Harriet will lead. Each musician is independent, yet the two violins must play together to make the music come alive. The violinists also resemble reason and emotion, each providing counterpoint to the other, yet both blending to produce harmony.