Authorship Discontinuities of El Ingenioso Hidalgo don Quijote de la Mancha as detected by Mixture-of- Experts

In the literary world, authorship of great novels
is like writing a great piece of music; while
there may never be a perfect way to determine
if someone wrote a particular work or not,
equations and algorithms have been developed
in information theory and statistics to help
those trying to discover the true authorship of
contested written works. Because no method is
perfect, using a set of methods on the same
works can be used to give high probabilities
of authorship. The JGAAP system houses
a collection of methods such as Histogram
Distance and Manhattan Distance and event sets
such as word bigrams and character trigrams
to allow users to perform multiple tests on
contested works to see if the supposed author is
actually the author by comparing samples from
both the contested author and other possible
authors.
We apply this framework and show a notable
discontinuity in the authorial style of the novel
El Ingenioso Hidalgo don Quijote de la Mancha
,
better known as
Don Quijote
(or
Don Quixote
).
1. Background
While there have been skeptics and scholars
alike that have doubted Miguel de Cervantes
Saavadre's true authorship of the entirety of
Don Quijote
, no one had tested whether or not
Cervantes was in fact the true author of the
whole of
Don Quijote
. The purpose of using
the JGAAP system was to either give merit to
or disprove this theory. By comparing to other
authors who wrote works at about the same time
Don Quijote
was written, the JGAAP system
would test to see if the text that Cervantes
supposedly wrote was closer to the first volume
of
Don Quijote
or closer to other authors of the
same time period. If a definitive break could
be established between where the program
attributed Cervantes as the author and where
it did not, that would suggest either a major
style shift or the presence of another author
different from Cervantes, while no break at all
would suggest that Cervantes was in fact the true
author of the second volume of
Don Quijote
,
assuming that he was also the author of the first
volume.
2. Methods and Materials
For this authorship attribution, the program
JGAAP 4.0 was downloaded from
http://w
ww.jgaap.com
, developed by Patrick Juola at
Duquesne University. The
Don Quijote
text
used was acquired from Project Gutenburg
at
http://www.projectgutenburg.org
. The full
text of Don Quijote was then stripped of the
introductions and separated into chapters by
volume. The first volume was then set as
the basis for Miguel de Cervantes' original
authorship. Every third chapter, starting with
chapter three, was used as the base case for
Cervantes' work. Two other authors used for
comparison, Fransisco de Quevedo and Mateo
Alemán, were also used. Quevedo's,
Historia
de la vida del Buscón, llamado Don Pablos,
ejemplo de vagamundos y espejo de tacaños
and Alemán's Guzmán del Alfarache
were
also taken from Project Gutenburg and broken
into roughly the same number of chapter-
type sections as the number of chapters used
for Cervantes'
Don Quijote
. In order to make
sure that Cervantes' was actually the author
of volume one of
Don Quijote
, every chapter
not used in the base case was compared to the
base chapters, Quevedo's work, and Alemán's
work. Each test used JGAAP's Normalize
Whitespace, Strip Punctuation, and Unify Case
canonicizers on all of the documents. Five
event sets - Word, WordBiGram, WordTriGram,
WordTetraGram, and Word Length - were
all paired with nine analysis methods -
Camberra Distance, Cosine Distance, RN Cross
Entropy, Histogram Distance, Kullback Leibler
Divergence, Levenshtein Distance, Manhattan
Distance, KS Distance, and Naive Bayes

2
Classifier, for a total of 45 unique event set-
analysis methods. Once the first volume of
Cervantes' work was confirmed to be uniformly
Cervantes', volume two of
Don Quijote
was
tested in the same manner as the first volume in
order to provide an accurate analysis.
We apply a mixture-of-experts approach to the
evaluation of authorship. Each different method
is treated as a single "expert" in different aspects
of authorial style, and permitted to vote on
who (among the candidates) is the author of
any specific fragment. If all 45 test "experts"
vote on Cervantes, we consider this to be strong
evidence supporting his authorship, while if only
5 or so of the 45 consider Cervantes to be
the most likely author, we consider this to be
evidence
against
.
3. Results
As a result of the analysis on the second volume
of
Don Quijote
, the JGAAP program indicated
that starting at chapter 6 Cervantes was not
the author. Out of the 45 tests run on each
chapter, the chapters in the first volume had
a mean of 37.54 occurrences of Cervantes as
the author with a standard deviation of .852.
The first five chapters of the second volume had
a mean of 36.50 occurrences of Cervantes as
the author with a standard deviation of 1.517.
Chapters 6-74 of the second volume, however,
had a mean of 4.90 occurrences of Cervantes
as the author with a standard deviation of
1.436. This radical shift in authorship means
either Cervantes completely shifted his writing
technique or he did not write the latter 69
chapters of the second volume of
Don Quijote
.
4. Discussion
While there are people who are skeptic about
the authorship of
Don Quijote
, nothing up until
now has given those claims any grounds other
than speculations based on inconsistencies
in the text. Although this analysis does not
guarantee that Cervantes did not write the last
69 chapters of the second volume, it does make
the probability of that claim much greater. This,
in part, is due to the fact that none of the
tests in JGAAP has been tested enough to show
that it will work for all documents. As further
analysis of the methods continues, the results
of the tests used in this authorship attribution
will most likely validate these results. As tests
and methods prove to not work, the analysis
will be redone with these tests omitted from the
analysis giving a more accurate result.