The Red Thumbmark · Chapter
A Suspicious Accident explained
Thorndyke and Jervis discuss the evidential value of fingerprints and the various hypotheses in the Hornby case.
What happens
Thorndyke and Jervis discuss the evidential value of fingerprints and the various hypotheses in the Hornby case. Jervis presents his theory that John Hornby, facing financial difficulties from mining investments, may be the thief. Thorndyke praises Jervis's reasoning and warns against over-reliance on fingerprint evidence. Later, a suspicious accident occurs when Thorndyke is nearly struck by a falling object, hinting at foul play.
Themes in this chapter
Forensic Science and Evidence
Thorndyke critiques the over-reliance on fingerprint evidence, emphasizing the need for corroboration and logical reasoning.
Observation and Deduction
Jervis constructs a hypothesis based on financial motives and Thorndyke's inductive method is praised.
Characters to notice
- Dr. John Evelyn Thorndyke
Discusses fingerprint evidence and hypotheses with Jervis; praises Jervis's theory; later involved in a suspicious accident.
- Dr. Christopher Jervis
Presents his theory of the crime involving John Hornby's financial troubles; reflects on Thorndyke's hidden knowledge.
- John Hornby
Mentioned as having financial difficulties from mining investments; considered a suspect in the robbery.
- Reuben Hornby
Discussed as the accused; Thorndyke expresses conviction of his innocence.
- Walter Hornby
Jervis recounts a conversation with him about John Hornby's financial troubles.
Key passages
“The kind of syllogism that they do make is this— 'The crime was committed by the person who made this fingerprint. But John Smith is the person who made the fingerprint. Therefore the crime was committed by John Smith.'”
Thorndyke criticizes the flawed reasoning that assumes the fingerprint alone proves guilt without considering whether the print was made during the crime.
Highlights Thorndyke's skepticism of fingerprint evidence as infallible.
“This theory of yours, Jervis, does great credit to your ingenuity. We may disregard the improbability, seeing that the alternative theories are almost equally improbable, and the fact that emerges, and that gratifies me more than I can tell you, is that you are gifted with enough scientific imagination to construct a possible train of events.”
Thorndyke commends Jervis for thinking creatively and constructing a plausible hypothesis despite its unlikelihood.
Shows Thorndyke's encouragement of imaginative yet logical reasoning.