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Professor Moriarty

Professor Moriarty is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Professor Moriarty rather than just read about it. In short: Professor James Moriarty is a fictional character and criminal mastermind created by Sir Arthur Conan Doyle to be a formidable enemy for the author's fictional detective Sherlock Holmes. He was created primarily as a device by which Doyle could kill Holmes and end the hero's stories.

Professor Moriarty — main illustration
Professor Moriarty — illustration

Key takeaways

  • Professor Moriarty belongs to mathematics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Professor Moriarty to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Professor Moriarty from memory before moving on to harder problems.

Reference excerpt

Professor James Moriarty is a fictional character and criminal mastermind created by Sir Arthur Conan Doyle to be a formidable enemy for the author's fictional detective Sherlock Holmes. He was created primarily as a device by which Doyle could kill Holmes and end the hero's stories. Professor Moriarty first appears in the short story "The Adventure of the Final Problem", first published in The Strand Magazine in December 1893. He also plays a role in the final Sherlock Holmes novel The Valley of Fear, but without a direct appearance. Holmes mentions Moriarty in five other stories: "The Adventure of the Empty House", "The Adventure of the Norwood Builder", "The Adventure of the Missing Three-Quarter", "The Adventure of the Illustrious Client", and "His Last Bow". Moriarty is an international criminal gang leader who uses his intelligence and resources to provide criminals with crime strategies and sometimes protection from the law, all in exchange for a fee or a cut of profit. Holmes likens Moriarty to a spider at the centre of a web and calls him the "Napoleon of crime", a phrase Doyle lifted from a Scotland Yard inspector referring to Adam Worth, a real-life criminal mastermind and one of the individuals upon whom the character of Moriarty was based. Despite appearing only twice in Doyle's original stories, later adaptations and pastiches have given Moriarty greater prominence, often using him as the main antagonist, and treated him as Sherlock Holmes' archenemy.

Appearances in works Professor Moriarty's first appearance occurred in the 1893 short story "The Adventure of the Final Problem" (set in 1891). The story features consulting detective Sherlock Holmes revealing to his friend and biographer Doctor Watson that for years now he has suspected many seemingly isolated crimes to actually all be the machinations of a single, vast, and subtle criminal organisation. After investigation, he has uncovered Professor Moriarty as a mastermind who provides strategy and protection to criminals in exchange for obedience and a share in their profits. Moriarty realizes Holmes is aware of his operation and confronts him in person, threatening death if Holmes interferes any further. Holmes describes Moriarty's physical appearance to Watson, saying the professor is extremely tall and thin, clean-shaven, pale, and ascetic-looking. He has a forehead that "domes out in a white curve", deeply sunken eyes, and shoulders that are "rounded from much study". His face protrudes forward and is always slowly oscillating from side to side "in a curiously reptilian fashion". Holmes mentions that during their meeting, Moriarty remarked in surprise, "You have less frontal development than I should have expected," indicating the criminal believes in phrenology. Holmes ignores the threat and delivers appropriate evidence to the police so Moriarty and those who operate his network will face justice in a few days. Knowing the mastermind and his trusted lieutenants intend to kill him before they hide or are arrested, Holmes flees to Switzerland, and Watson joins him. The mastermind follows, his pursuit ending when he confronts Holmes at the top of the Reichenbach Falls. Watson does not witness the confrontation but arrives later to find signs of hand-to-hand combat occurring at the cliff edge near the waterfall, indicating the battle ended with both men falling to their deaths. Watson also finds a goodbye note left behind by Holmes that Moriarty allowed him to write before their battle. Moriarty plays a direct role in only one other Holmes story, The Valley of Fear (1914), set before "The Final Problem" but written afterwards. In The Valley of Fear, Holmes attempts to prevent Moriarty's men from committing a murder. A policeman who interviewed Moriarty tells Holmes that the professor has a painting by Jean-Baptiste Greuze hanging on his office wall. Learning this, Holmes mentions the great value of another painting by the same artist, pointing out such works could not have been purchased on a university professor's salary. The work referred to is La jeune fille à l'agneau; which some commentators have described as a pun by Doyle on a famous Thomas Gainsborough painting, the Portrait of Georgiana, Duchess of Devonshire, which was taken from the Thomas Agnew and Sons art gallery. The gallery believed Adam Worth (the criminal who helped inspire Doyle to create Moriarty) was responsible, but was unable to prove the claim. Holmes mentions Moriarty in five other stories: "The Adventure of the Empty House" (the immediate sequel to "The Final Problem"), "The Adventure of the Norwood Builder", "The Adventure of the Missing Three-Quarter", "The Adventure of the Illustrious Client", and "His Last Bow" (the final adventure in Holmes's canon timeline, taking place years after he has officially retired). Doctor Watson, even when narrating, never meets Moriarty (only getting distant glimpses of him in "The Final Problem"). Watson relies upon Holmes to relate accounts of the feud between the detective and the criminal. Doyle is inconsistent on Watson's familiarity with Moriarty. In "The Final Problem", Watson tells Holmes he has never heard of Moriarty, while in "The Valley of Fear", set earlier on, Watson already knows of him as "the famous scientific criminal." In "The Empty House", Holmes says Moriarty commissioned a powerful air gun from a blind German mechanic surnamed von Herder, a weapon later used by the professor's employee/acolyte Colonel Moran. It closely resembles a cane, allows easy concealment, is capable of firing revolver bullets at long range, and makes very little noise when fired, making it ideal for criminal sniping. Moriarty also has a marked preference for organising lethal "accidents" to befall his targets. His attempts to kill Holmes include falling masonry and a speeding horse-drawn vehicle. He is also responsible for stage-managing the death of Birdy Edwards, making it appear the man was lost overboard while sailing to South Africa.

… excerpt ends here. Continue reading the full article.

Illustrations

Professor Moriarty illustration
Professor Moriarty: Simon Newcomb (circa 1905), one possible model for Moriarty
Simon Newcomb (circa 1905), one possible model for Moriarty
Professor Moriarty: George Boole (circa 1860), another possible model for Moriarty
George Boole (circa 1860), another possible model for Moriarty

Worked examples

Example 1 — a first encounter with Professor Moriarty

Start with the simplest possible case. Write down what Professor Moriarty claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Professor Moriarty before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Professor Moriarty ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Professor Moriarty

In research
Professor Moriarty appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Professor Moriarty in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Professor Moriarty is common in secondary-school and first-year university syllabi. It links to neighbouring topics America's Best Comics characters, Crime film characters, Fictional British criminals, so understanding it makes those chapters shorter.
In everyday life
Look for Professor Moriarty outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Professor Moriarty in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Professor Moriarty means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Professor Moriarty out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Professor Moriarty in simple terms?

Professor James Moriarty is a fictional character and criminal mastermind created by Sir Arthur Conan Doyle to be a formidable enemy for the author's fictional detective Sherlock Holmes. He was created primarily as a device by which Doyle could kill Holmes and end the hero's stories.

Why does Professor Moriarty matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Professor Moriarty?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Professor Moriarty.

Tags

  • America's Best Comics characters
  • Crime film characters
  • Fictional British criminals
  • Fictional English people
  • Fictional crime bosses
  • Fictional criminals in films
  • Fictional criminals in television
  • Fictional gentleman thieves
  • Fictional mathematicians
  • Fictional scholars and academics
  • Fictional scientists in literature
  • Literary characters introduced in 1893

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