Appearance vs. Reality

The book repeatedly challenges characters and readers to distrust what seems probable and believe the incredible, as seen in the epigraph and the detectives' constant reinterpretation of evidence like the suicide vs. murder debate.

The epigraph directly warns against trusting what seems probable, highlighting the theme that appearances can be deceiving and that truth often lies in the unexpected.

The initial appearance of a suicide is questioned, hinting at a possible murder.

The club members discuss how people's outward lives (e.g., Brotherhood's business, Davenant's religion) conceal unknown realities, and how witnesses distort facts through inference.

The peaceful golf course contrasts with the violent death; the body initially appears to be a sleeping tramp but is revealed to be a murder victim.