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The Wisdom of Father Brown · Chapter

The Mistake of the Machine explained

Father Brown and Greywood Usher debate the guilt of Drugger Davis, a man accused of conning women out of money and possibly poisoning one.

What happens

Father Brown and Greywood Usher debate the guilt of Drugger Davis, a man accused of conning women out of money and possibly poisoning one. Usher believes his 'machine' (a lie detector or psychological test) proves Davis innocent of a prison warder's murder, but Father Brown argues that Davis's character—a sneaky, patient swindler—is incompatible with the violent, daring escape and murder. Their discussion is interrupted by a ragged, furious man who bursts in demanding Davis's release. Usher then reveals he has captured the escaped convict Oscar Rian, who was heading toward Pilgrim's Pond, the estate of millionaire Ireton Todd. Father Brown questions the evidence linking Rian to the murder, pointing out inconsistencies.

Themes in this chapter

  • Appearance vs. Reality

    The chapter contrasts the apparent innocence of Drugger Davis (based on the machine's results) with his actual criminal character, and the violent escape of Rian with the possibility that he is not the murderer.

  • Crime and Morality

    Father Brown distinguishes between different types of criminality—fraud and poison versus violent murder—arguing that a person's moral character is consistent across their sins.

Characters to notice

  • Father Brown

    Debates with Usher about the nature of guilt and character, arguing that a swindler like Drugger Davis would not commit a violent prison break.

  • Greywood Usher

    The prison governor who captured the escaped convict Oscar Rian using his walking stick, and who defends his 'machine' as proof of Davis's innocence.

  • Drugger Davis

    The prisoner whose guilt or innocence is debated; Father Brown believes he is guilty of fraud and poison but not the warder's murder.

  • Ireton Todd

    The millionaire owner of Pilgrim's Pond, mentioned as the likely target of the escaped convict Oscar Rian.

Key passages

  • Why, bless us all! ... Why, because he's guilty of the other crimes! ... You seem to think that all sins are kept together in a bag. You talk as if a miser on Monday were always a spendthrift on Tuesday.

    Father Brown argues that a person's crimes reflect their character; a sneaky swindler would not suddenly become a violent murderer.

    Highlights the theme of crime and morality, showing Father Brown's nuanced view of human nature.

  • He didn't storm a spiked wall against a man with a loaded gun. He didn't write on the wall with his own hand, to say he had done it. ... He didn't write his own initials in a man's blood.

    Father Brown lists the violent actions of the real murderer, contrasting them with the timid methods of Drugger Davis.

    Emphasizes the distinction between different types of criminal behavior.

The Wisdom of Father Brown — The Mistake of the Machine Explained