# Bayes Centre News: The Bayes Centre celebrates the life of Thomas Bayes

Two hundred and seventy years ago today, Thomas Bayes passed away, leaving a legacy that continues to impact the world today.

Two hundred and seventy years ago, a University of Edinburgh alumni, statistician, philosopher and Presbyterian minister named Thomas Bayes died, aged just 59. In his lifetime he published two works, one philosophical and one mathematical, but it was something that was left unpublished "An Essay towards solving a Problem in the Doctrine of Chances" which has gone on to be his main legacy and which continues to be relevant to the world today.

Surprisingly little is known about the life of Thomas Bayes. He was likely born in Hertfordshire to a prominent nonconformist family and in 1719 he enrolled in the University of Edinburgh to study logic and theology.

Thomas Bayes was elected as a Fellow of the Royal Society in 1742, a significant honour that was likely the result of his paper Introduction to the Doctrine of Fluxions, as he is not known to have published any other mathematical works during his lifetime.

It was to the Royal Society that his essay was presented after his death, by Richard Price. In it was his now famous theorem which put simply, describes the probability of an event based on prior knowledge of conditions that might be related to this event.

A very basic example could be the way that an internet search engine generates its results

Searching for “rosebud” brings up the famous movie Citizen Kane as the top result. The search engine has picked this not from any understanding of movie or horticulture, but by using lots of previous searches to know what the searcher is probably looking for. It calculates this probability using Bayes’ Theorem.

At its core, Bayes Theorem introduced a way of calculating how you should update your belief in a fact, given both your previous knowledge and the new information you observe. This concept was ground breaking for its time. Statistics were not highly regarded as an area of mathematics and this way of putting them to use was brilliant. Bayes work mirrors that of the great philosophical ideas about putting the focus on observation and experience to derive truth.

In many ways Bayes’ method is what makes evidence-based decision making possible in a precise, mathematical way and enables us to build the data-driven systems which are all around us today.

Bayes theorem has applications as wide as playing poker to being used to crack the infamous Nazi Enigma code in World War II. It is used in artificial intelligence, finance, climate change, cancer research and a vast number of other areas, but it can equally be used by anyone who is investigating a problem, even school children.

It is this inclusiveness and ability to be used by everyone that led to the Bayes Centre being named for Thomas Bayes. Bayes’ Theorem is key to much of the work done at the Bayes Centre, and today on the anniversary of his death, we recognise and celebrate his famous contribution to the world.

## Who was Thomas Bayes?

Video: Thomas Bayes
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