# Karl Pearson: biography of this mathematician and biostatistician.

**A biography of Karl Pearson, a very influential biostatistician in psychology research.**

Karl Pearson has been one of the most important statisticians, although he did not originally plan to become one. He actually studied a bit of everything, ranging from the pure sciences, such as physics, through biology, studying law and, oddly enough, German history.

To him we owe many statistical tools that psychologists and others working in the health and social sciences use for just about everything, such as the chi-square or linear correlation.

**In this biography of Karl Pearson we will look at the life of this great historical figure** who, with his light and dark sides, has determined the history of any discipline that considers itself to be scientific.

## Brief biography of Karl Pearson

**Karl Pearson was an English historian, lawyer, mathematician, biometrician, professor and biographer.**. Among his interests were writing about folklore, researching philosophy, learning about Germanic culture and, also, following the socialist theses and admiring Karl Marx. But apart from all this, what stands out most about Pearson was being the contributor in the birth of applied statistics and using it as a fundamental tool in all knowledge that was considered scientific.

Pearson's contributions to statistics as we know it today are many, the most notable being linear correlation and the χ2 method. In addition, **is considered as one of the promoters of incorporating women in science and intellectual debates.**knowledge at that time reserved for the male gender. However, it also has controversial aspects such as being a supporter of eugenics influenced by Francis Galton.

### Early years and education

**He was born Carl Pearson, with a C, on March 27, 1857 in London, England.**. His family was originally from Yorkshire, upper-middle class and puritanical. His father was a lawyer, something that perhaps influenced Pearson's life years later when he decided to study law. The young Pearson was educated at home until he was nine years old. After that he began studies at University College School in London until he was sixteen.

Due to health problems he had to leave school momentarily and was assigned a private tutor at home. Despite adversity, he was able to win a scholarship to the prestigious King's College of Cambridge University to study mathematics, which he completed in 1879.

Although he came from a fairly religious background, Karl, at the age of 22, rejected Christianity and adopted freethought. **rejected Christianity and adopted freethought, interpreting it as a kind of faith but not a religious one.**. Despite being a freethinker, he preferred to distinguish his beliefs from those of traditional freethinkers.

### Visit to Germany

After finishing his studies at Cambridge, he traveled to Germany with the intention of studying physics and metaphysics at the University of Heidelberg and also visited the University of Berlin, where he studied law. But he would not only study law and exact sciences during this period, but also medieval history and German literature between 1879 and 1880.

In fact, **his eagerness and interest in learning about medieval German made him well known in the field, so much so that he was later offered a position in Germanic studies at Cambridge University upon his return to England.**He was later offered a post in Germanic studies at Cambridge University on his return to England. One of his works from this period, the result of his passionate interest in Germany, is "The New Werther", greatly influenced by Johann Wolfgang von Goethe.

It was around this time that, by a quirk of fate, his original name, Carl, became Karl at the age of 23. The reason was due to a simple typo made at the University of Heidelberg. **As the young Karl Pearson was an admirer of Karl Marx, he made this small confusion a sign of his identity.**Thus he acquired the name Karl, with a German K, for the rest of his life.

### Back to England: the Men and Women's Club

In 1881 he began to study law, although he never practiced as a lawyer. Later, in 1885, he obtained a position as professor of mathematics at the University College where he gained a reputation as a good, though somewhat heterodox, teacher. During this period he published "The Common Sense of the Exact Sciences" and "History of the Theory of Elasticity".

Karl Pearson, **apart from being a great mathematician and man of science, was interested in ethics and the history of Christianity.**He also considered that gender should not be an obstacle to debate intellectual issues. For this reason, in 1885 he founded the Men and Women's Club, a discussion forum whose purpose was to allow free discussion between both genders.

It was at the Men and Women's Club that he met the woman who would become his wife, Maria Sharpe. With Maria he had three children, Sigrid Loetitia, Helga and Egon, and they lived happily until her death in 1928, Karl Pearson marrying a colleague from the University of London, Margaret Child, the following year.

### Pearson, Galton and Welton

It was in 1890, when Karl Pearson was 33 years old, that a very important event occurred in his life, a life in which he had studied mathematics but had not yet studied statistics in depth. **He began to become interested in statistics thanks to Charles Darwin's cousin, Francis Galton**who a year earlier had published his book "Natural Inheritance".

In 1891 he became professor of geometry at Gresham College, where he would establish contact with one of the most important zoologists of the 19th century, Walter Frank Raphael Weldon, founder of biometry. The relationship between Pearson and Weldon was fruitful, leading Karl to acquire knowledge in biometry and evolutionary theory. It was Weldon who introduced Pearson to Galton.

Pearson, encouraged by Weldon, began to take a deeper interest in the mathematics describing the processes of heredity and evolution and, as a result, published a series of papers on regression analysis, correlation coefficient as well as introducing the χ2 test (chi or chi-square).

**The relationship between Galton, Weldon and Pearson was a beautiful one, resulting in the founding of the journal Biometrika**whose anecdote is worth commenting on. Pearson presented a paper to the Royal Society which, despite being very well worked, was rejected by the biologists of the Academy who did not like his mathematical analysis. As a consequence, Weldon suggested that he create his own journal and, with the help also of Galton, the three of them founded their own journal.

### Closer ties with eugenics and later years

It is here that we begin to see one of Pearson's dark sides because of the influences of Francis Galton who is considered by many to be the founder of eugenics. **Galton put Pearson in charge of his office for eugenics and attached his Laboratory of Biometrics to it, resulting in the founding of the Department of Eugenics.**resulting in the founding of the Department of Applied Statistics at University College.

It must be said that we can neither deny nor reject Pearson's contributions because he was a eugenicist. In his time, this current had the support of many scientists and intellectuals, and eugenic programs were applied in democratic countries governed by both the right and the left. However, we should also not forget that **Nazism made very strong use of the eugenic theses and social Darwinism**The Nazis, who advocated artificial selection in human beings to improve our species, should not be forgotten.

His admiration for Galton lasted until his death in 1911. His admiration for Galton was such that Pearson went so far as to say that Francis Galton and not Charles Darwin would be the most prodigious grandson and that he would be the most remembered of Erasmus Darwin. It was then that Karl Pearson decided to do the biography of Darwin's cousin.

The work was published in the form of three volumes that came out in 1914, 1924 and 1930. He used multiple resources as a bibliography, including letters, narratives, genealogies, commentaries and photographs by Francis Galton. This work exalted Galton's life, work, and personal legacy for Pearson. Pearson himself put out of his own pocket so that these books could be printed.

Upon Galton's death, Karl Pearson left part of his estate to the University of London for a research position in eugenics. Following the wishes of his late mentor, Pearson incorporated the biometric laboratory and Galton's laboratory. Karl Pearson would remain in that department until his retirement in 1933, although he continued to work on a variety of projects until his death **continued to work on various projects until his death on April 27, 1936 at the age of 79.**.

## Works by Karl Pearson

There are several texts, articles and books by Karl Pearson. As a great intellectual of his time, with a multifaceted profile touching both pure sciences and humanities, **it is not surprising that his books include mathematics, philosophy, history and religion.**. Below is a list of some of his works.

- The New Werther (1880)
- The Trinity, A Nineteenth Century Passion Play (1882)
- Die Fronica (1887)
- The Ethic of Freethought (1886)
- The Grammar of Science (1892)
- On the dissection of asymmetrical frequency curves (1894)
- Skew variation in homogeneous material (1895)
- Regression, heredity and panmixia (1896)
- On the criterion that a given system of deviations from the probable in the case of a correlated system of variables is such that it can be reasonably supposed to hove arisen from random sampling (1900)
- Tables for Statisticians and Biometricians (1914)
- Tables of Incomplete Beta Function (1934)

Referencias bibliográficas:

- Gómez Villegas, M.A. (2005) Inferencia Estadística, Madrid: Díaz de Santos.
- Pearson, K. (1900) On the criterion that a given system of deviations from the probable in the case of a correlated system of variables is such that it can be reasonably supposed to have arisen from random sampling, Philosophical Magazine 5 th series, 50, 157-175.
- Pearson, K. (1978) The History of Statistics in the 17 th and 18 th Centuries, Edited by E.S. Pearson. New York: MacMillan.
- Pearson, K. (1895) Contributions to the mathematical theory of evolution, II: skew variation. Philosophical Transactions of the Royal Society of London, A, 186, 343-414.
- Pearson, K. (1896) Contributions to the mathematical theory of evolution, III: regresion, heredity and panmixia, Philosophical Transactions of the Royal Society of London, A, 187, 253-318.
- Pearson, K. and Filon, L.N.G. (1898) Contributions to the mathematical theory of evolution, IV: on the probable errors of the frequency constants and on the influence of random selection on variation and correlation. Philosophical Transactions of the Royal Society of London, A, 191, 229-311.
- Stigler, S.M. (1986) The History of Statistics: The Measurement of Uncertainty before 1900, Cambridge: Belknap Harvard.

(Updated at Apr 13 / 2024)