Collapse follows a five-point framework, not a single cause

Diamond proposes that societal collapses typically result from some combination of five factors: environmental damage caused by the society itself, climate change independent of human action, hostile neighbors, the loss of friendly trading partners a society depended on, and — the factor Diamond treats as most decisive and most within human control — the society's own political, economic, and cultural response to these pressures.

Not every collapse involves all five factors, but Diamond argues that examining any specific historical collapse through this checklist reveals how rarely a single cause is sufficient on its own. Environmental damage alone, for instance, is rarely fatal to a society that has healthy trade relationships and responds adaptively; it becomes catastrophic mainly when combined with rigid social responses that prevent course correction.

This framework is Diamond's central diagnostic tool throughout the book, letting him compare wildly different societies — Pacific islanders, Greenland Norse settlers, Maya city-states — on a common analytical footing rather than treating each collapse as a unique, unrelated historical mystery.

Takeaway: societies rarely die from one wound — they die from several wounds combined with a refusal to treat any of them in time.