One of the central themes of 'A Paradise Built in Hell' is the spontaneous altruism that people exhibit during disasters. Solnit provides numerous examples of individuals and communities coming together to help one another, often at great personal risk. This challenges the notion that humans are inherently selfish and suggests that our true nature is more cooperative and compassionate than we might think.

Solnit introduces the concept of 'temporary utopias' that form in the aftermath of disasters. These are moments when social norms and hierarchies are upended, and people experience a sense of equality and solidarity. These fleeting utopias reveal the potential for a more just and connected society, offering a glimpse of what could be possible if we reimagined our social structures.

The book also addresses the widespread myths about social deterioration during crises, such as looting and violence. Solnit argues that these myths are often exaggerated or unfounded, and they serve to justify authoritarian responses to disasters. By debunking these myths, she encourages a more nuanced understanding of human behavior in times of crisis and advocates for responses that prioritize community and mutual aid.