Poe’s Sherlock: Dupin as a Blueprint for Holmes
BA Thesis English Language and Culture, Utrecht University
The Aesthetics of Detection
Helène Pannekoek
3658708
A. M. W. Kager
June 2015
7801 Words
Inhoud
Abstract ................................................................................................................................................... 2
Introduction ............................................................................................................................................. 3
Method .................................................................................................................................................... 4
The Authors & Characters ....................................................................................................................... 5
Sir Arthur Conan Doyle ...................................................................................................................... 5
Edgar Allan Poe................................................................................................................................... 5
Sherlock Holmes ................................................................................................................................. 6
C. Auguste Dupin ................................................................................................................................ 7
Scientific Methods................................................................................................................................... 8
The Morelli Method ............................................................................................................................ 8
Fingerprints ....................................................................................................................................... 11
Chemical Substances ......................................................................................................................... 12
Psychology ............................................................................................................................................. 16
Interpreting the clues ......................................................................................................................... 17
Mathematics.......................................................................................................................................... 19
Class ....................................................................................................................................................... 22
Society ............................................................................................................................................... 22
A Comparison ........................................................................................................................................ 25
The Purloined Letter versus A Study in Scarlet .................................................................................. 25
Conclusion ............................................................................................................................................. 28
Works Cited ........................................................................................................................................... 29
1
Abstract
Was C. Auguste Dupin used as a model for Sherlock Holmes?
The stories about C. Auguste Dupin and Sherlock Holmes share many similar features
so it seems that Arthur Conan Doyle has used Poe’s detective as a model for Sherlock
Holmes. In college, Conan Doyle acquired medical information from his professor Joseph
Bell, whose deductions baffled him at the time. It seems that Arthur Conan Doyle
incorporated these deductions in his stories. Arthur Conan Doyle used Bell’s character as
well; he admired how Bell used the art of deduction (Ravin, 239). He was pleased with
Dupin’s way of thinking but also saw that there was room for improvement in the scientific
method. This is implied in “A Study in Scarlet” (Doyle 24), when Holmes comments on C.
Auguste Dupin.
Conan Doyle started to combine Poe’s setup and storylines for a detective story while
incorporating some traits of Joe Bell. The character of Dupin is not complete in any sense, it
needed some more depth and characteristics. So Conan Doyle added these. He also added
more crime solving methods than Poe had ever used, because this was possible due to new
discoveries in crime solving techniques had emerged (Snyder 107). These additions did not
distance Holmes too far from the stories of Dupin, since they still share many features that
indicate that Holmes was indeed based on Dupin.
2
Introduction
Sherlock Holmes is one of the most famous detectives on earth. Even today, his influence on
society is clearly visible in the form of several TV series (such as Elementary, Sherlock, and
The Adventures of Sherlock Holmes), films, articles in magazines, the Sherlock Holmes
Museum in London, and many memorabilia. Clearly, the detective is popular among an
immense audience. This leads to the question of his origin; on what is he based? Mentions of
Sherlock Holmes being based on C. Auguste Dupin are easy to find, such as “Bayesian
Thought in Early Modern Detective Stories: Monsieur Lecoq, C. Auguste Dupin and Sherlock
Holmes” by Joseph B. Kadane, or an article in The Guardian: “Murders in the Rue Morgue:
There’d have been No Sherlock Holmes without Detective Dupin” by Sam Jordison. These
are very short mentions of the likeness of both detectives but these do not give a detailed
explanation of why they are so similar.
The gap that exists between these statements and what is in the stories needs to be
closed, so understanding the Sherlock stories becomes easier. By comparing Sherlock Holmes
and C. Auguste Dupin, the source for Conan Doyle’s stories will become apparent. This thesis
will examine the Sherlock Holmes series, his character, and his methods with the goal of
finding out their origin.
3
Method
The method by which the main question is answered is a comparison of the detective stories
by Edgar Allan Poe and Sir Arthur Conan Doyle. This is not the only source of information,
since we should also look at the authors and their inspirations, and the time in which Poe and
Conan Doyle lived and wrote their stories. Scientific discoveries in Conan Doyle’s time also
contributed to the development of Sherlock Holmes and thus these should not be overlooked.
Articles written about Edgar Allan Poe or Sir Arthur Conan Doyle will be compared to
establish enough background information to start from. The next step is to compare articles
and stories about Sherlock Holmes and C. Auguste Dupin to find out what they have in
common and where they differ. Furthermore, the articles provide information about sciences
that were new around the time that the stories were written, starting in 1887 with “A Study in
Scarlet” (Doyle 15-86), and they give insight in where the knowledge of these detectives
comes from.
4
The Authors & Characters
Sir Arthur Conan Doyle
Sir Arthur Conan Doyle was born in Edinburgh in 1859. According to the background story in
Conversations with Arthur Conan Doyle, he grew up in a catholic family with a father, who
was an unsuccessful artist and who had developed a habit of drinking, and a mother who was
Irish (Parke 17). Her family could be traced back to Irish nobility. This may have sparked his
interest in chivalry (Parke 17). He started his medical profession, first as a doctor, at the
University of Edinburgh in 1876, where he met professor Joseph Bell. This professor would
later on play an essential part in the Holmes series (Parke 22-23). Arthur Conan Doyle went
on a whaling boat when he was twenty, and worked as a doctor (Parke, 22) for seven months
and he returned to university in the fall of 1880, completing his studies (Billings 40).
Afterwards, he went on a ship to the West coast of Africa as a doctor (Billings 40). When he
returned to England, he opened a private practice as a physician as well as a pharmacist, since
that was common practice (Billings 41). His practice was not very successful but he started
writing his stories during that period and these were profitable (Cheshire V). Eventually he
would give up on medicine so he could dedicate his time to writing. He did not let go of
medicine altogether, since he would incorporate much of his knowledge into his stories.
Edgar Allan Poe
Edgar Allan Poe was born in Boston in 1809. The information from John J. Moran’s “A
Defense of Edgar Allan Poe: Life, character and Dying Declarations of the Poet. An Official
Account of his Death” is as follows: Poe’s parents died when he was just a child and Mr.
Allan adopted him (26). He was brought to Europe, where he attended school (27). He was
spoiled and this made him very sensitive and gentle. His “tenderness of heart was so well
known as to make [him] the jest of [his] companions”(28). He went to the University of
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Charlottesville where he was dismissed for his temper. It turned out that these were false
accusations (28). He is often portrayed as addicted to alcohol but this was denied by several
people, including William Gowans, a bookseller in New York who knew Poe well. He stated
that : “I never saw him the least affected by liquor, nor ever descend into any known vice. He
was one of the most courteous gentlemen and intelligent companions that I have met during
my haltings and journeyings through divers divisions of the globe” (41). He married his
young cousin Virginia Clemm in 1836. She was the girl mentioned in the poem “Lenore”
(Poe 746-47) and she would later die from pulmonary disease (Moran 39). The woman from
the poem “Annabel Lee” (Poe 738) was Mrs. Shelton, whom he was about to marry at the
time of his death. They were engaged when he was younger, when she was still Miss Royster
(Moran, 50). How he died is still unknown, since it is unclear whether he died from the effects
of alcohol and drugs or not.
Sherlock Holmes
Sherlock Holmes, the fictional character from Sir Arthur Conan Doyle’s detective stories is
well-known for his methods of deduction. He is portrayed as a “loner, with obsessive,
fanatical and addictive traits” (Cheshire ix). He was an expert in disguise; whenever he
dressed up not only his clothes changed, but also his “expression [and] manner” (Doyle 170).
His addictive traits included the use of cocaine (Dalby 73), and large amounts of tobacco and
coffee (Doyle 683). He has knowledge of many subjects, including facial expressions (Jann
694), “poisons, hand-writing, stains, dust, footprints, traces of wheels, the shape and position
of wounds” (Snyder 107). Sherlock is also known for his reasoning, which he calls
deduction1. Sherlock does not like emotions, as Watson described: “All emotions [...], were
1
Finding a clue or detail and discover what is behind it by reasoning, e.g. by looking at ashes, Sherlock could
discover what brand of cigar was used.
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abhorrent to his cold, precise but admirably balanced mind. He was [...] the most perfect
reasoning and observing machine that the world has ever seen. [...] He never spoke of the
softer passions, save with a gibe and a sneer” (Doyle 161).
The description of Sherlock Holmes by Dr Joseph Bell is:
He created a shrewd, quick-sighted inquisitive man,
half doctor, half virtuoso, with plenty of spare time, a
retentive memory, and perhaps with the best gift of all-the power of unloading the mind of all burden of trying
to remember unnecessary details . . . . Sherlock Holmes
has the acute senses, and the special education and information
that make these valuable: and he can afford
to let us into the secrets of his method (qtd. in Ravin 239).
C. Auguste Dupin
Dupin comes from a wealthy family but lives a more humble life. He is not a professional
detective but solves cases for his own pleasure; only in the case of The Purloined Letter he
accepts a financial reward (Poe 130). His knowledge of mathematics as well as several other
subjects makes him a great reasoner. He observes more than others and does not always
accept the statements made by the police (Poe 131) and the newspapers (Poe 44-46). Dupin
was interested in more than just reasoning, he acquired the knowledge needed to solve crimes,
such as the decomposition of bodies in water (Poe 40-42). He also has knowledge about
botany which is mentioned in The Mystery of Marie Rôget when he compares the growth
time of grass and fungus (Poe 53). Further, Dupin has a fine memory (Poe 137) and knows
how to imitate handwriting (Poe 137).
7
Scientific Methods
The stories of Poe and Doyle are similar in some areas and sometimes they have a likewise
plot, which will be explained further on pages fourteen and fifteen. However, there are major
differences, especially in the way they use science. Poe incorporated reasoning and some
mathematics in his stories but Conan Doyle added more techniques, such as discovering blood
stains by using a chemical substance and knowledge of poisons (Billingss 42-43). This can be
explained by the different periods in which Poe and Conan Doyle lived. At the time that Poe
wrote his stories, which is between 1841 and 1844, not many methods for crime solving had
been developed. Many new discoveries were made in the period in which Doyle wrote his
stories, between 1887 and 1927. According to Snyder, he incorporated these so soon after
their discoveries that some people believe that he made them up himself and that science
followed his lead (107).
The Morelli Method
An important aspect in the detective stories of Poe and Doyle is that they have ability to solve
mysteries by looking at details that can be easily overlooked. For instance, in “The Murders in
the Rue Morgue” Dupin finds a nail in a window that is supposed to keep it shut but upon
further investigation he discovers that the window can actually be opened and that this was
the way to escape the locked room (Poe 17).
Holmes also looks at details as small as Dupin; in “The Resident Patient”, Holmes
discovered that a death that was believed to be a suicide, was in fact a homicide committed by
three men. He made this discovery by looking at cigar butts that were found at the scene. He
discovers that different types of cigars were smoked and he was able to link these to the men
who smoked them (Doyle 433).
8
The analysis of seemingly unimportant clues was used by Poe in his stories, the nail in
a window that was mentioned earlier was one of those clues. Other examples are: the
arrangement of the surroundings where Marie Rôget’s belongings were found (Poe 55),
identification of a knot as a sailor’s knot (Poe 59) , and the way in which a fabric was torn off
(Poe 55). Sherlock Holmes however uses this technique more often for instance when he
notices that papers on a desk had been moved (Doyle 597), a damaged window-sash
indicating that a bullet was fired (519), or even a clay and chalk combination that shows
Holmes where someone came from (Doyle 219). The skill of linking small details or clues to
a bigger part and finding the truth behind them comes from the field of art history. It is not
known if Conan Doyle actually read about the Morelli method but the identification of a
person by looking at the ears in “The Cardboard Box” by Conan Doyle strongly resembles
this method. This fact was also used as evidence by Enrico Castelnuovo, an art historian who
compared Holmes’ deduction to Morelli’s method in “Attribution” (782). Further, an article
by Morelli explains why this method is so useful for identification. “Between 1874 and 1876
a series of articles on Italian painting was published in the German art history journal
Zeitschrift für bildende Kunst. They bore the signature of an unknown Russian scholar, Ivan
Lermolieff” (Ginzburg, 7). It turned out that this Lermolieff was actually the Italian scholar
Giovanni Morelli.
Morelli changed the way paintings were identified. Before Morelli’s method was
described and distributed, paintings were identified by focussing on the larger details of a
painting, such as the eyes of the way in which a smile was painted. Morelli suggested that
much more could be discovered by comparing details that are put in a painting without
thinking about them. He argued that “personality should be found where personal effort is
weakest” (Ginzburg 9). So whilst a painter focusses on large details and facial expression, he
would not put too much effort in ears or fingernails and precisely because of this, these details
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can tell the most about who painted it. This was of course a shock for others; details such as
fingernails were regarded as ‘beneath notice’ and trivial; the main focus for identifying a
painting was always on larger subjects in paintings. The way in which Morelli described the
key to identifying an object with the words “beneath notice” is an important factor in this
theory as well as in the Dupin and Holmes stories. In this theory, the noticing of an object
makes it easier for anyone to copy it but details that are considered irrelevant are not likely to
be copied carefully.
Although details are used for the identification of a painting, they can also serve
another purpose. “Mancini [...] said that an impression of character (the ‘spirit’) could be
drawn from what it produced (its ‘works’), all being rooted in the ‘characteristics’ of the
individual body” (Ginzburg, 18). This meant that the content of a letter could provide
information about its writer, in the sense of intelligence and character, through the way in
which it was written. Later on, this idea was taken over by Camillo Baldi in his Treatise on
how to tell from a letter the nature of its writer (qtd. in Ginzburg). Mancini had no interest in
information about characters through graphology, “he was struck, however, by one
proposition in the new discipline, that is, the variety of different handwritings and the
impossibility therefore of imitating them” (Ginzburg, 18). The impossibility of imitating
handwritings can be directly linked to Morelli’s theory about how details are almost
impossible to imitate and can therefore make a distinction between an original and a fake.
Small details are also important for hunting; for many thousands of years, people have
been using all sort of clues to come closer to the animal that they are hunting. They used
tracks in the sand, droppings, and looked at what type of animal was near by identifying the
paw- or hoof prints. This type of tracking and tracing is exactly what the detectives would do
when hunting for criminals; and according to Ginzburg this is what “inspired Poe [and]
indirectly Conan Doyle” (23).
10
Fingerprints
Fingerprints are one of the main sources for identification but this method was not used until
the late nineties. Before this discovery, other methods to identify a person were used. First, a
“word-portrait” (Ginzburg 26) was used for identification. Ginzburg explains that in the
“Graeco-Roman period” people had to give their names and a detailed description of their
“appearance” for officials, which was not a reliable method (24). This changed for the better
when people had to sign documents in the late 18th century, which fit Camillo Baldi’s theory
on handwriting. However, this method was not enough when more laws and punishments
became official in the “last decades of the 19th century” (Ginzburg 25). The development of
the criminal justice system lead to a rise in criminals, as more actions were forbidden, and this
created a demand for the precise identification of convicted criminals. A new method was put
forward by Alphonse Bertillon, who suggested the “careful measuring of physical details”
(Ginzburg 25). This method was flawed, since it could only prove that someone did not
commit a crime, since many people have the same measures, so it could only be proven that
persons with different measures could not possibly have committed the crime. Due to this
problem, he suggested a combination of this “anthropometric system” with a “word-portrait”
that would give additional information (Ginzburg 26). This created even more problems, since
it relied on the description of an object but descriptions are always subjective (Ginzburg 26).
Eventually, the use of fingerprints was introduced in the British colonies, where, as
Ginzburg describes it, most “natives were illiterate [...] and to the eyes of a European all
looked the same” (27). The fingerprint system was first used in 1858 by Herschel (Barnes, 11)
and it solved the problems of describing an object accurately and needing words in an
illiterate environment, and it made it possible for Europeans to distinguish between the native
inhabitants of the British colonies.
11
It was this development of identification that would later be used in the Poe and
Sherlock stories, for the stories often give a description of the culprit similar to the wordportrait as described by Alphonse Bertillon. One example is the description of the Orang-utan
in “The Murders in the Rue Morgue”, which was obtained by combining eye-witnesses’
reports with observations made at the crime scene; they reported that they saw a killer with
non-human hair (Poe 21), superhuman strength because a body was put high up in the
chimney (Poe 8) , and a voice resembling a human voice but not in any recognisable language
and “no syllabification” (Poe 19). In addition to this, fingerprints were also present in “The
Murders in the Rue Morgue”, on “the throat of Mademoiselle L’Espanaye” (Poe 21). This
profile eventually lead to the identification of a missing orang-utan as the killer. Fingerprints
were also used as a method for identification in the Holmes stories; for example, in “The
Adventure of the Norwood Builder”, a thumb-print was used to frame another person. This
print was taken from a seal and copied with wax, after which blood was added to this wax and
the print was then pushed against a wall (Doyle 509). So the use of fingerprints was
incorporated in the Holmes stories but earlier methods were used by Dupin. A fingerprint was
only mentioned by Poe but not in any way used as a form of identification in itself, since the
method became common practice after Poe had written his stories. However, both stories
make use of the method present at the time, and Holmes also uses word-portraits and
measurements, so that is what they have in common.
Chemical Substances
Another area of expertise of Sherlock Holmes is the knowledge of poisons. In “A Study in
Scarlet” it is mentioned that he conducted many chemical experiments in the university’s
laboratories but this was not an official study; he did this in his free time out of curiosity
(Doyle 16). It is also quite possible that he consulted a materia medica; according to Billingss,
12
he used The Essentials of Materia Medica and Therapeutics written by Alfred Baring Garrod
and a version of this book has been found which contains annotations from Arthur Conan
Doyle (Billingss 37-38). Some of these notes were written as a verse to facilitate the
recollection of information:
Slow Arsenic Poisoning
Vomiting - plenty of stools
Pain in the stomach & bowels
Pulse Wiry. Forehead feels stuffy
Eyes are red and are puffy,
The Last of the symptoms may seem a,
Slight one, and that is eczema.
ACD (qtd. in Billingss 39).
Doyle eventually had knowledge of many different areas of medicine; he was “the first to
draw attention to the hasty world-wide use of tuberculin as a cure for tuberculosis in 1890
after analysing its effects (Muresan 122). He was also interested in medical bacteriology: he
predicted that many diseases were caused by bacteria, while at that time, only few diseases
were known to be caused by bacteria (Muresan 122). An analysis of his works suggests that
he was aware of new discoveries and “trend in medicine” (Muresan 122).
The knowledge of chemical substances was often acquired through testing on a subject –
often the examiner himself. It was common to just take something and describe what was
happening. Arthur Conan Doyle did this too:
13
Several years ago,[...] a persistent neuralgia led me to use the tincture of gelseminum
to a considerable extent. I several times overstepped the maximum of the text-books
without suffering any ill effects. [He] ‘determined to ascertain how far one might go in
taking the drug, and what the primary symptoms of an overdose might be.’ He
increased the amount of drug on a daily basis, well past the point usually suggested as
a limit, until ‘diarrhoea . . . [became] so persistent and prostrating’ that he gave up the
experiment (Billingss 41).
It was not only Conan Doyle who did this, for example, researcher Cristison tested the
Calabar Bean on himself. In order to understand the Calabar bean and its active ingredient,
physostigmine, he ingested it and almost died (Ravin 240).This type of experimenting can be
found in the Sherlock Holmes stories too. In “A Study in Scarlet” an acquaintance, Stamford,
tells to Watson that:
[he] could imagine hi[m] giving a friend a little pinch of the latest vegetable alkaloid,
not out of malevolence [...] but simply out of a spirit of inquiry in order to have an
accurate idea of the effects. To do him justice, [he] think[s Sherlock] would take it
himself with the same readiness (Doyle 17).
In “The Resident Patient”, the medical knowledge of both Sherlock and Watson is made very
clear, since they are consulted by Dr Trevelyan whose patient needs medical attention (Doyle
426). C. Auguste Dupin’s adventures did not include solving a crime caused by or including
poisons, but Poe’s “The Imp of The Perverse”, in which a poisoned candle was used in a room
that was not ventilated properly (Poe 274), may have been an inspiration for “The Adventure
of the Devil’s Foot” by Arthur Conan Doyle (Billings, 45), in which a poison was put in a
14
lamp. In both stories, the devil is mentioned as the source for death and madness instead of
the real reason: poison.
Many other chemical substances are used in the Holmes stories, such as:
alkaloids, ammonia, amyl nitrate, belladonna, chloroform, cocaine, curare, ether,
hormones, morphine, opium, prussic acid, snake venom, and strychnine. This is the
highest number of drugs that has appeared in a series of detective stories. Several
poisons are mentioned as well, but in most cases their nature is not specified (Muresan
122).
All in all, the medical knowledge of both Holmes and Watson comes from Conan Doyle’s
own knowledge. His professor Joseph Bell, once implied that Conan Doyle has modelled both
characters after himself (Muresan 123). This seems realistic because a characters knowledge
has to come from the writer, but the way in which it is used can be based on other stories. The
similarity between “The Imp of the Perverse” and “The Adventure of the Devil’s Foot” is an
indication that even the use of certain poisons was not all made up by Conan Doyle himself.
15
Psychology
The detective has to know a lot about human behaviour, since this will help him find the
missing person, understanding the antagonist, or predict what will happen next. Edgar Allan
Poe demonstrates this knowledge in “The Purloined Letter” by using the ‘hidden in plain
sight’ trick (Poe 136); an object can best be hidden by leaving it on the table as a nonimportant item. In “The Purloined Letter”, Dupin seems to be able to read his companion’s
mind; but further explanation shows that he is actually able to follow the thoughts of his
companion by close observation (Poe 6-7). Holmes does the same thing in “The Resident
Patient” where he refers to this conversation (Doyle 423).
Further, in “A Study in Scarlet”, Holmes "claimed by a momentary expression, a
twitch of a muscle or a glance of an eye, to fathom a man's inmost thoughts. Deceit, according
to him, was an impossibility in the case of one trained to observation and analysis” (Doyle 23
). This type of observation was also used by Dr Joseph Bell, who not only looked at his
patients’ symptoms but also uses information about their recent behaviour (Jann 686). This
type of observation is called “pathognomy, the reading of emotions from facial expression”
(Jann 693). In addition, Holmes relies on “thorough predictability of human behavior” (Jann
689), so he can easily determine what is going to happen next and what his course of action
should be.
Another trick of the mind that Sherlock uses is his way of handling data. He “has a
brain like a great storehouse of apparently miscellaneous and irrelevant facts” and he can
enter this “warehouse” to find information at the right time (Jann 690). This is also described
in “A Study in Scarlet”, where the brain is compared to an “attic [and] there comes a time
when for every addition of knowledge you forget something that you knew before. It is of the
highest importance, therefore, not to have useless facts elbowing out the useful ones” (Doyle
21).
16
Although it seems that Dr Joseph Bell’s way of thinking is used as a model for
Sherlock Holmes, Watson mentioned him in “A Study in Scarlet” and Holmes reacted by
mentioning that he was an “analytical genius [...] but [...] by no means such a phenomenon as
Poe appeared to imagine” (Doyle 24). This proves that Conan Doyle has read Dupin and tried
to improve him. Further, not a mention of the memory of Dr Bell was made, whereas a great
memory was also ascribed to detective Dupin in “The Purloined Letter” (Poe 137).
Interpreting the clues
Key to finding the right information is the ability to ask the right questions and being able to
look beyond presumptions. This ability comes from the skill of applying some imagination to
the facts already found or known. In “The mystery of Marie Rôget” there are a number of
assumptions that are proven wrong by Dupin. He takes the information given by either the
police or the newspapers and explains to his companion why they are incorrect. He starts by
explaining why the time of death is incorrect (Poe 42) and goes on by asking if the presumed
victim really is Marie Rôget (Poe 42). He continues to talk about the crime scene, which is
seen as proof that she was killed by a “gang of blackguards” (Poe 51). By combining the way
in which the evidence was placed, the drag marks, and the probability of a large struggle
when one girl is outnumbered by four men, he eliminates the possibility of a group of killers.
A group would have never left evidence behind and definitely not displayed clothes on rocks.
That group would also carry the body instead of dragging is along. They would have lifted the
body over a fence instead of cutting it and then dragging it through the hole. Finally, the girl
would have been no match for a gang and a struggle would not have taken place. Instead, the
girl would be held by a few men and that is it.
Dupin then turns towards the evidence that suggests that an individual was responsible
for the murder. The pieces of clothing would not be retrieved, since the murderer would have
17
to return to the scene which increases the chance of getting caught. Furthermore, the way in
which the clothing was wrapped around the body fits the idea that the body needed handles to
be dragged away. This was not necessary if more people were involved. A struggle usually
happens between two people, and should one of them die and the other needs to drag the body
away, that is a reason why the body needs handles. Otherwise, the handles as well as the
struggle do not make any sense (Poe 57).
In addition, Dupin argues that a group is highly unlikely because the reward for
solving the mystery is great. In “The Mystery of Marie Rôget” Dupin argues that one of the
group members would have come forward to talk about his companions and get a sum of
money (Poe 59) if it would have been a group instead of one person.
Holmes’ skill to interpret clues is widely known. He was able to tell that Watson had
been in Afghanistan (Doyle 18) and he is able to combine the presence of several items into
one conclusion, as he did in “The Adventure of the Speckled Band”, when a bell-rope,
mysterious whistles, and the sighting of a speckled band all turned out to be connected to the
mysterious death of Julia Stoner (Doyle 272-273). In the same story, he notices that the client,
Helen Stoner, had come to visit him by dog-cart and the train due to some mud on her left arm
and a partial train ticket (258-259). The observation of clues by both detectives is often build
on smaller details that must be combined to a solution for the problem.
18
Mathematics
The solving of crimes is often related to the probability that a certain event has occurred. It is
crucial to keep in mind that the probability has to be estimated correctly. What often happens
is that the total probability “adds
up to more than 1.00, thus
violating the ‘fundamental
convention’ of probability theory
(Wallendael and Hastie 240). 1.00
“Three models of cognitive representations for hypothesis testing”
represents a certainty, in other
words: 1.00 is the equivalent of
Source: “Tracing the Footsteps of Sherlock Holmes: Cognitive Representations
of Hypothesis Testing”. By Lori Van Wallendael and Reid Hastie. Memory &
Cognition. 18.3 (1990)
100%. In their research, Robinson and Hastie found that subjects rating a clue that contributed
to suspicion towards one person, did not decrease the probability for other suspects in their
subjects opinions (in Wallendael and Hastie 240). One theory is that these suspects are not
linked to each other but treated as “independent cognitive entities” (240). This is what Teigen
calls the “independence hypothesis” (qtd. in Wallendael and Hastie, 241). The visual
representation of this hypothesis shows how the possibilities are not affected by each other.
Dupin seems to solve mysteries in a similar way as this theory explains but he did
consider that the increase in probability A must lead to a decrease in probability B. In “The
Mystery of Marie Rôget” he states that “It would have been a miracle indeed, if, while a gang
of ruffians were perpetrating, at a given locality, [...] another similar gang, in a similar
locality, in the same city, under the same circumstances, with the same means and appliances,
engaged in a wrong of precisely the same aspect, at precisely the same period of time” (Poe
52). Another example of the use of mathematics from the same story is that he is not surprised
that no one has seen Marie, even though she was known by many people. He explains that the
people who knew her in relation to all Parisians are few and takes into account the various
19
routes Marie could have taken and combines this with the day and time on which she
disappeared. This looks more like the following theory; because he accepts ideas that lead to
the next possibility until one probability remains: that nobody has seen Marie.
This theory is Shafer’s theory and the
main point is that the possibilities are
connected, but not as Bayes2 described. Shafer
came up with an idea that is more accepted;
namely the “theory of belief functions”
(Wallendael and Hastie 241). This theory
encompasses that a subject believes all
probabilities (e.g. A, B, C, D are equally
plausible) until evidence excludes options
“Hierarchy of Hypothesis Sets and Subsets within a Belief
System”
Source: “Tracing the Footsteps of Sherlock Holmes:
Cognitive Representations of Hypothesis Testing”. By Lori
Van Wallendael and Reid Hastie. Memory & Cognition. 18.3
(1990)
(so now we end up with B, C, D). This
exclusion continues until only one option is left.
This seems to be the type of representation that Sherlock Holmes uses. He often
eliminates options, for example, in “The Red Headed League” he explains why not all redheaded men will be qualified for a job: only those from London can apply. They have to be
“grown men” and cannot have “light red, or dark red, or anything but real bright, blazing,
fiery red” (Doyle 179) hair. In “The Adventure of the Engineer’s Thumb” Holmes says: “the
mystery clears gradually away as each new discovery furnishes a step which leads on to the
complete truth” (Doyle 274). This is exactly what happens in Shafer’s theory.
However, Holmes does not only rely on the method explained by Shafer. In “Silver
Blaze” he mentions that “improbable as it is, all other explanations are more improbable
still”(Doyle 339). This is more similar to the acceptance of a probability with the least
2
Where the total probability is 1.00, as mentioned earlier.
20
counter-evidence; as is the case in the independence hypothesis. This is supported in “The
Reigate Puzzle”, when he mentions that it is important to distinguish between “incidental and
[...] vital clues” (Doyle 407) and that there are as much as twenty-three possible deductions
(Doyle 408).
In conclusion, both Holmes and Dupin use various mathematical concepts for their
inclusion or exclusion of probabilities and they both use clues and their own knowledge to
find a solution for the problems at hand.
21
Class
Class is also an important factor in the stories. The wealth of both characters leads to the
choice of having a roommate for example. The description of their class also puts them in a
context for the reader and makes their social connections more probable. Due to the loss of a
family fortune, Dupin needs a creditor and someone to share the rent with (Poe 4) and in “The
Murders in the Rue Morgue” only a small reward is offered (Poe 23). In this story, he lives in
a “time-eaten and grotesque mansion” and “ books [...] were his sole luxuries (Poe 4). He has
connections with the police and eventually even with the highest circles of Paris, when he has
to find a missing letter for a royal person in “The Purloined Letter” (Poe 126).
Unlike Dupin, Holmes lives in apartment in London but he too needs someone to
share the rent with (Conan Doyle 16). He also receives rewards for his work every now and
then. He is proud of his work but he knows that the police will take credit for his work; they
come to him for advice (Conan Doyle 26). Holmes also has important clients, such as the
nobleman in “A Scandal in Bohemia” (Doyle 164). So both Dupin and Holmes are from the
same class, which is another example of the resemblance between Holmes and Dupin. They
also share the same attitude towards some groups and vice versa; their relations with the
police are similar.
Society
In the Holmes stories, all classes are made typical but “the upper classes are more likely to
elude the determinism of such typing” (Jann, 687). Sherlock himself is an example of this,
since he is a master of disguise and is able to dress up and act as any class he prefers. Jann
also argues that the working classes easily reveal their employment by how they look and in
what materials they are covered, whilst middle- and upper classes are more difficult to put
into categories (691). Holmes classifies the upper classes by looking at their external marks
22
(e.g. the ears of the Baskervilles) and the hereditary behaviour. Moriarty’s behaviour is
described in “The Final Problem” as coming from “hereditary tendencies of the most
diabolical kind. A criminal stain ran in his blood” (Doyle 470-71).
In addition, the lower class people did not trust the police at the time. The police were
not clever enough, they got their information from crooks. The general impression was that
“If the police came from outside the city slums, they were not clever enough; if they came
from the inside, they were not honest enough” (Harper 69). The Strand, which published the
Holmes stories, aimed at the middle classes and provided information in addition to the
stories, for example: it provided additional information about ears after The Adventure of the
Cardboard Box (in which ears were important clues) (Harper 73). By doing so, the people
could also acquire some of the knowledge of the detective and it got them more involved in
the stories.
Additionally, The Strand published a series called ‘Crime and Criminal’ that provided
insight in the ways of the underworld and people learned about how to prevent crime. Most
crimes were identity- and property-related (Harper 74) and this was also part of the Holmes
stories. Other detective stories were usually only written about murder. Here we find a
connection to the Dupin stories, since Dupin not only investigated a murder but he also helped
solving the problem of a missing letter. Altogether; “the fictional detective, one who had
inside knowledge, who knew the language of the underworld, yet whose loyalties lay with the
bourgeois, the property owners, fulfilled a social need (Harper 69).
Moreover, Holmes’ income is an important factor in the stories. It gave him the status
of a gentleman as well as it assured a steady factor that kept him from being bribed. He also
knows people from different parts of the city and has acquaintances on all levels.
What also made him popular, is that he did belong in the city because “neither the country nor
the sea presented the slightest attraction to him” (Doyle 888). A detective novel was often
23
regarded as vulgar and commonplace, but the intellectual aspect in the Sherlock Holmes
stories appealed to a new public (Harper 72).
In contrast to Holmes’ high income and status, Dupin did belong to the aristocracy but
he has lost his family fortune. William Crisman suggests that “moneylessness produces a deep
mental wound [and that Dupin] literally shutters his own windows, and adopts a practice of
living near darkness” (216). Dupin starts investigating out of interest but this gradually
becomes his source of income. In the first case, his debts are paid off instead of him receiving
a reward (Crisman 220) and in “The Purloined Letter” he “receiv[es a] check for fifty
thousand francs” (Crisman 220). He also started a case in a regular street and ended up
working for the highest social class; which would indicate that his ability to solve crimes gave
him back his social status.
24
A Comparison
Before concluding anything, it is necessary to closely examine stories. Two stories will be
compared are “The Purloined Letter” and “A Study in Scarlet”. They were chosen because
they both describe the detective well; Dupin’s character has developed and is now more easily
identifiable whereas Sherlock is described in great detail by Watson. Furthermore, the
mysteries both revolve around searching a house or room, which make them suitable for
comparison.
The Purloined Letter versus A Study in Scarlet
“A Study in Scarlet” is clearly based on “The Purloined Letter”, since they have many
features in common. The narrator, the contacts of both detectives, some skills, personality,
and the way in which the rooms are searched are all similar. In addition to this, Conan Doyle
has included features of both other Dupin stories, “The Murders in the Rue Morgue” and “The
Mystery of Marie Rôget”.
The narrator in both stories is, or eventually becomes, a close friend of the detective3,4.
The narrator observes almost everything the detective does but sometimes leaves a blank
space, since he does not always know what the detective knows or suspects. The absence of
information keeps the reader interested and wanting to continue reading the story.
Furthermore, both detectives have a similar set of skills. One example of this is
Dupin’s knowledge of “analysis” and “mathematical reasoning” (Poe 134) and Sherlock’s
“calculation” (Doyle 33) and “science of deduction and analysis” (Doyle 23). They both have
the ability to put clues together and see what has happened in the past. They also speak Latin
(Poe, 134 and Doyle, 38). In both stories, interpreting letters is mentioned. Dupin compares
3
4
In The Purloined Letter: page 125.
In A Study in Scarlet: page 15.
25
letters on signs in the streets (Poe 136) and Sherlock interprets letters written on the wall, and
insisted these were not written by a real German (Doyle 33). They are also both men of
science but Dupin has knowledge of physics and metaphysics (Poe 135) and Sherlock knows
much about chemistry (Doyle 22) and anatomy (Doyle 16).
Additionally, the detectives share personality features. In “The Purloined Letter”,
Dupin is described as someone who smokes a pipe (Poe, 125 and 130), he has some “odd
notions” (Poe 125), he does give some credit to the police but at the same time says that he is
better (Poe 131). Dupin also likes to play a bit with his opponent and enjoys winning (Poe
138). Sherlock’s personality as described in “A Study in Scarlet” is that he is “a little queer in
his ideas” (Doyle 16), he smokes (Doyle 19), he states that “he [, detective Gregson,] knows
that I am his superior” (Doyle 27), and after solving a mystery he calls it a “little mystery”
and has a “pleasant smile” (Doyle 51), indicating that he is proud to have solved the case.
Moreover, both cases include a house that has to be searched thoroughly by the police.
In both stories it becomes apparent that the police has done everything within their power and
knowledge to find clues. This is described in more detail in “The Purloined Letter” but both
searches were futile. In “The Purloined Letter”, the letter was overlooked because it was
hidden in plain sight; in “A Study in Scarlet” clues were not found because they were too
small, such as the ashes (Doyle 33), or they were hidden in a dark corner, such as the word
“Rache” (Doyle 31-32), or they were overlooked because they were outside the room, such as
the tracks and footsteps (Doyle 32).
Finally, Conan Doyle incorporated elements from two other detective stories in “A
Study in Scarlet”. Watson compares Sherlock to Dupin (Poe 24), and Sherlock mentions
Dupin’s retracing his friend’s thoughts in “The Murders in the Rue Morgue” (Poe 6-7). Conan
Doyle also incorporated newspaper clippings in A Study in Scarlet, which was also a feature
in “The Mystery of Marie Rôget”. The newspaper clippings provide the point of view form
26
the police and the public, and are clearly not even close to being the solution of the mystery.
The news in both stories comes from different newspapers but the difference is that the
newspapers are explicitly mentioned in “A Study in Scarlet”, and they mention the political
interpretation of the murder, but the newspapers in “The Mystery of Marie Rôget” focus more
on the details of a case and what they could mean. In this comparison, the articles from Poe’s
story seems more realistic and less absurd than Conan Doyle’s clearly overdoing it.
In conclusion, “A Study in Scarlet” has many similarities with Edgar Allan Poe’s
detective stories; “The Purloined Letter” in particular. Both stories have the same type of
narrator, the detectives have some skills in common, and their personalities are comparable.
The searching of the house in “The Purloined Letter” and the investigation of “A Study in
Scarlet” is done in a similar way; the detectives both have to step in to find the necessary
information. In “A Study in Scarlet”, Conan Doyle has found a way to take elements from the
two other Dupin stories and adapted them so they would fit in with his own mystery.
Altogether, these features all point in the direction of C. Auguste Dupin as an example for
Sherlock Holmes.
27
Conclusion
In conclusion, there is much evidence that Sherlock Holmes was indeed based on C. Auguste
Dupin. The detectives have much in common and Conan Doyle even mentioned Dupin in his
works, so the only conclusion is that Poe’s detective stories were indeed a model and a source
of inspiration for Conan Doyle.
Both detectives were great in reasoning and had similar character traits, since they
were both men of reason instead of emotion. They are also known to have a great memory
which they use to store facts until they are needed again. Holmes and Dupin were from the
same class and status, and they also ended up working for the upper-class. Both men have
knowledge in many areas of science and that knowledge is used for all kinds of interpretations
and ultimately for solving a case. The detectives are able to find clues that nobody else could
find; they are able to interpret these clues, and the same types of mathematical reasoning are
used for finding a solution for different types of enigmas. For this particular skill, they were
both praised and consulted by the police. Fingerprints and poisons were mentioned by Poe as
well as Conan Doyle; the difference is that it was possible for Conan Doyle to actually use the
fingerprint as an identifier. The writings of Poe and Conan Doyle also had similarities in some
of the plots and they used the same type of narrator for their stories. The difference between
the detectives is that new techniques had emerged at the time of Conan Doyle’s writings and
these were used in his stories.
In addition, he did admit that Joseph Bell was an example for him but the same type of
reasoning has been used by Poe’s Dupin as well; Bell’s manner was an addition of Conan
Doyle but does not seem to be the entire foundation on which Holmes was built. All in all, the
stories show overlap in so many areas that in conclusion, Poe’s Dupin was indeed used as a
blueprint for Conan Doyle’s Sherlock Holmes.
28
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