Casaubon's Changing Credulity
Foucault's PendulumCasaubon moves from archival skepticism through playful pattern-making toward paranoia, then regains some clarity without escaping the consequences of his involvement.
increasing
Bearing strength in each event
decreasing
Evidence and Doubt

A Methodical Beginning
Documentary history
Casaubon chooses philology and studies the Templar trial through primary sources. His father's warning about commercial motives has taught him to distrust easy claims.
Curiosity remains
He enjoys the collision of ideas without necessarily believing them. Belbo's invitation to the publishing world offers a new arena for his curiosity.
The Habit of Resemblance

Patterns Become Convincing
Connecting everything
Casaubon gathers references and helps turn them into the Plan. The repeated practice of finding analogies makes suspicion automatic, despite his claim that the exercise is only a joke.
Lia's warning
Lia argues that common bodily experience explains many supposed universal symbols. Casaubon understands her point but continues to seek hidden patterns.
A Night of Paranoia

The Search Continues
Fear after the rite
Casaubon interprets Paris's streets and monuments as evidence that the conspirators control the city. He seeks reassurance but finds further apparent signs.
Partial understanding
He later recognizes that the Plan was invented and that it nevertheless became real for those who believed it. Understanding does not immediately restore his peace or safety.
As a university student
During Project Hermes
After the Conservatoire gathering