The novel explores sanity and insanity as being products of society and whether or not people fit into society and are able to express themselves or not within the somewhat narrow confines of societal judgement. A classic example of this is Connie, who in her affair with Deacon, which is clearly an affair that society does not allow them to pursue. In addition, an intriguing element to this affair is when in Chapter 7 Connie bites Deacon's lip and drinks his blood. This is something that would be identified as being insane behaviour, and Deacon, in his response, does not appreciate this. However, this could be viewed as being yet another element of Connie's identity that cannot fit in nor be accepted within society. Rather, this novel presents acts as neither insane nor sane, but justified entirely by society at large. The major example of this is of course the slaughter of the women that the men of Ruby carry out:

They shoot the white girl first, but the rest they can take their time. No need to hurry out here. They are 17 miles from a town which has 90 miles between it and any other. Hiding places will be plentiful in the convent, but there is time, and the day has just begun. They are nine. Over twice the number of the women, they are obliged to stampede or kill, and they have the paraphernalia for either requirement--rope, a palm leaf cross, handcuffs, mace, and sunglasses, along with clean, handsome guns.

Such violence could be viewed as insane, but society gives them a logic and a rationale that makes this violent act chillingly palpable and acceptable. Sanity and insanity therefore are presented as fluid terms which allow normal people to be viewed as outcasts and horrific acts to be justified. There are no essential, discrete categories of sanity and insanity; society and what is deemed as being "normal" is used as the major guide.