Who is George Boole? Why the genius's invention of Boolean logic is today's Google Doodle
George Boole, the British mathematician whose work on logic laid many of the foundations for the digital revolution, has been honoured on the 200th anniversary of his birth with a special Google Doodle.
The Lincolnshire-born academic is widely heralded as one of the most influential mathematicians of the 19th century, devising a system of logic that aimed to condense complex thoughts into simple equations.
His legacy was Boolean logic, a theory of mathematics in which all variables are either "true" or "false", or "on" or "off". The theory preceded the digital age, with American Claude Shannon applying Boolean logic to build the electrical circuits in the 1930s that led to modern computers.
Google's animated Doodle illustrates the logic gates that are used in computing and are derived from Boolean functions.
The first "g", the two "o"s, the "l" and "e" in the Google logo light up based on the logic gates underneath them. When the "x" and "y" in the second "g" light up, they are on, activating other letters at different times.
For example, when both x and y are on, the first "g" (x AND y) and the second "o" (x OR y) light up.
The "XOR" gate that activates the first "o" is known as an "Exclusive OR" gate, meaning it only turns on when one and only one of x or y are true.
Nowadays, this logic underpins all digital devices, existing in almost every line of computer code, and has transformed the way we live our lives.
For example, searching Google for two words, say "David Cameron", includes an "AND" function, meaning both the values "David" and "Cameron" need to show up in search results.
Boole, who lived much of his life as a professor at University College Cork in Ireland, was also an early thinker on the theory of artificial intelligence, believing that all human thought could be reduced to a series of mathematical rules, and advocating machinery as a way to replace human drudgery.
He was born on November 2 1815 in Lincoln and died aged just 49 in 1864.
The Doodle can be seen around the world in November 2, except for the US, Mexico, Italy and parts of the Middle East and Africa.