Symbolism, Imagery, Allegory
Creepy, unnatural silence is a sign of Peter Quint's presence in both his first appearance and when he shows up inside the house on the staircase. In the first of these scenes, the Governess, who is strolling happily outside, notices that everything goes quiet when the mysterious figure appears, even the peaceful sounds of birdsong. This is a signal that something abnormal and certainly unnatural is happening – even though she doesn't yet know that he's a ghost yet, she can already tell that he's not meant to be there.
Inside the house, the silence is even more marked; though this close encounter seems more "human and hideous" (9.6), the lack of conversation between the Governess and her nemesis is what really makes it freaky. Finally, when the Governess actually tries to speak to one of the ghosts (Miss Jessel in the schoolroom, 15.5), the ghost does not – or cannot – answer.