The isolation of Lois and Susan compares in terms of betrayal being the cause; in terms of the doubts (e.g., about their children) and questions (e.g., whose fault) that are raised; in terms of inability to reconcile life aspects. The isolation of Lois and Susan contrasts more significantly and includes contrasts in age during events and at the beginning of isolation; in emotionalism and "intelligence"; in the roles of emotion and reason ("intelligence"); in the presence of despondency or absurdity in present life; and in the depth and effect of psychological instability.
Lois's and Susan's ages contrast during the stories narrative period. Lois's tragic story--while told as a frame story set at Lois's retirement from family life--occurs when she is young, telling of events between when she was nine and thirteen. Lucy comes to camp when Lois is ten and steps "sideways" to disappear when she is thirteen. Susan's story, told as a frame story retrospective ("This is the story ... about a failure in intelligence .... They were older when they married...") begins when she is in her late twenty's and ends when she is "fortyish." Lois's isolation begins while she is a child, contrasting with Susan's isolation, which begins when she is a wife and mother.
The chronological structure of Lois's and Susan's stories contrasts. Lois's story inside the frame is told in flashback, which isolates her throughout the story because her adult isolation is born in her childhood. This contrasts with Susan's story, which, within the third-person retrospective frame, is told in continuing chronological order. This dramatizes the beginning moments of Susan's isolation, beginning with Matthew's first confession of infidelity. Lois's isolation begins in the past and bleeds into the present, while Susan's isolation begins in the present and is carried into the future.
Lois's story and tragedy is founded in emotionalism in contrast with Susan's story and tragedy being founded in "intelligence," that is in reasoning, not feeling. Lois's emotion isolates her because she is too overcome with weeping to insist that Cappie understand the truth about the absence of anger in her last moments with Lucy. Susan's intelligence isolates her because she rejects and denies her emotions while questioning the truth and meaningfulness of her love, her marriage and her children. One is isolated because of emotionality, the other because of intelligence, or reasoning.
Ironically, Lois is snagged into isolation by Lucy's and Caddie's faulty reasoning, while Susan is snagged into isolation by hers and Matthew's disruptive emotions. Lucy reasoned that going back to Chicago would be bad and that it was not dangerous to venture too near the cliff edge (suggesting her disappearance was an accidental fall: "like a cry of surprise, cut off too soon"), and Caddie reasoned that there had to be a comprehensible cause that Lois could provide to Lucy's disappearance. Susan couldn't accept the reasonableness of or cope with her erupting emotions, and Matthew couldn't contain his lustful emotions.
Lois is isolated because she feel despondence in her present life ("present" since she was thirteen). Contrastingly, Susan is isolated because she experiences the turmoil of the "absurd" in her present life (present, extending into her future). Lois and Susan compare because both feel further isolation because both question the reality of their children's births. The adult Lois of the frame says that she "can hardly remember, now, having her two boys in the hospital, nursing them as babies," and Susan feels that "her children were not her own."
Both women further compare because both are unable to reconcile aspects of their lives. Although they fail to reconcile different aspects, they compare in that Lois is unable to reconcile the mystery of the landscapes ("something, or someone, looking back out"), while Susan is unable to reconcile the meaning of Matthew's actions (are they meaningful or absurd?).
Lois and Susan contrast in the depths of their isolation because Lois felt Lucy lived on ("She is here. She is entirely alive."), while contrastingly Susan felt her life to be a desert. In comparison, both women have the same unanswered question prying at the corners of their minds: Who is at fault? In comparison, both women are betrayed by a loved one. Contrastingly, Lois is betrayed by Lucy, whether through foolhardiness or despair, and Susan is betrayed by Matthew through his fits of adultery.
Lois contrasts with Susan in that Lois suffers from the isolating, unremitting distraction of her tragedy and the projection of hope onto empty reality in landscape paintings, but Susan falls into the isolation of choking insanity, with the devil stranger tracking her and "the reflection of the madwoman" and her "meaningless tinkling laughter." In further contrast, Lois's isolation ends with Lucy alive with her, but Susan's isolation ends with tightly closed windows, a turned valve and escaping gas in a closed, isolated, room.