Purpose of the Woman

McCarthy needed something that is no longer present to represent life as it used to be in the time before.
The linear chronology of the novel means we have to follow the experiences of the man and the boy as they trek through America to the coast. However, the existence of the woman's character allows for an insight into what life was like pre-apocalypse. We get a picture of her character through the man's memories, who's descriptions of her vary from romantic ("summer dress") to angry ("the coldness of it"). The fact that the woman is no longer alive is pivotal as it implies that some people from the old world don't have what it takes to survive. The world has changed, both physically and in the way it works, since the apocalypse. The woman represents how good life was before the disaster, many allusions to her pre-apocalypse are in a positive light and associating her with happy events (for example, the trip to the theatre). In a way, her not being alive during the novel's story is indicative of how everything has changed and nothing will ever be the same again for the characters.

The man and woman represent the different ways in which humanity might react to such a situation.
The reactions of the man and woman to the apocalypse differ greatly. On the one hand, the man represents true strength and survival instinct. He disregards the emotional significance and danger he's in to think rationally. He conserves fresh water by turning the "taps as far as they would go" to fill the bathtub. This way, he is able to ensure both he and his wife have something to drink. However, the woman doesn't appear to understand this. Her immediate reaction is to panic and question why the man is filling the bath. She can't understand his instinct, which makes her seem weaker as she wouldn't be able to survive on her own.