In Iain M. Banks' novel "Excession," he introduces the concept of an Outside Context Problem (OCP), which refers to a significant and unexpected challenge that civilizations confront, often only once in their history. This challenge is likened to a period in a sentence; once it appears, it drastically alters the narrative and demands a response. The OCP forces civilizations to reassess their understanding and adapt to new realities beyond their previous experiences.

The notion of an OCP highlights the vulnerabilities inherent in any advanced society. Just as a full stop brings a sentence to a conclusion, an OCP can mark a pivotal turning point, requiring ingenuity and resilience. Such problems emphasize the unpredictability of existence and illustrate how civilizations must confront challenges that fundamentally reshape their trajectories.