The closing example compares Cunningham's relationships with Somerville and Philip Vian to show why the independence of corroborating witnesses matters. Cunningham and Somerville were friends, whereas Cunningham and Vian were highly effective colleagues without the same personal closeness. Agreement between the latter pair can therefore carry a different evidential weight from agreement between friendly correspondents who may share assumptions or loyalties. An entertaining anecdote about Cunningham, Somerville, and Dwight D. Eisenhower is kept explicitly tentative because the available evidence cannot verify all of its details. The uncertainty itself demonstrates how historians should separate a plausible story from a proven event.
Notable Point · 38:17-42:00
Treat relationships as part of corroboration
Agreement between accounts has different weight when the writers were friends, colleagues, or otherwise socially connected.