In this philosophical analysis of evil and good, Mary Scrutton (Midgely) casts doubt on the idea that the two concepts are diametrically opposed. The author encourages us to think about their interdependency and complementarity: without evil, there is no good, and vice versa. The central theme that Scrutton addresses, therefore, is what constitutes human nature. The corollary theme is what constitutes the social good and, by extension, how that quality can be extended to correcting tendencies towards wickedness in humans. Along with this, the theme of appropriate deployment of violence runs through the work.

Scrutton suggests that the human mind cannot truly comprehend pure evil, as it will always postulate a possible escape into goodness, especially as instigated by other people. Evil cannot, therefore, be part of human nature, but represents violation(s) of social norms—and in turn, it is correctible by social intervention. Scrutton addresses the fallacy that evil is a singular phenomenon. Instead, she examines the contextual use of violent aggression, contrasting such motivations as self-defense, protection of others, and warfare. She points out that the viewer’s perspective will affect their judgment of a perpetrator’s motivation.

Considering the influence of Sigmund Freud’s theories, Scrutton also takes on self-harm as an aspect of evil. If harm is not directed outward toward society, do the same conclusions about context logically follow? She interprets Freud as emphasizing alienation in such instances, where perceived distance from society refocuses the psyche inward so that self-harm may indicate extremes of alienation. Here, she draws on his revised ideas about eros and death formulated in the aftermath of World War I. By extension, motives for destruction of others may still be fundamentally self-focused; such actions may reflect an understanding that inflicting widespread damage (such as in suicidal attacks) will inevitably bring harm to the perpetrator.