*Throwback Thursday is a look back at some of the great minds in the history of computer science that have inspired Little Web Giants. This week’s story on George Boole was put together by Melanie.*

George Boole (1815-1864) was the son of a poor shoemaker in Lincoln, England, who had to leave school at 16 to support his family. Despite this setback, he grew to become a pioneering thinker who went on to lay “the essential groundwork for modern mathematics, microelectronic engineering and computer science”.

If you’ve ever used a search term such as “cats OR dogs” or “chips AND chocolate” then you’ve used Boolean logic. What you may not realise is that this logic is also the language of computer chips, and it all started with George Boole’s work in mathematical philosophy.

After founding his own school at the age of 19, Boole continued his own education by reading widely and making contacts with leading British academics. He developed a particular interest in algebra, and his research publications led to him becoming professor of mathematics at the University of Cork in Ireland.

Boole’s most important work, *An Investigation of the Laws of Thought*, took Aristotle’s rules for logical thinking and found a new way to express them using algebra.

In normal algebra, variables like x and y are set to numbers, like 7, 2.4, or pi. In Boolean algebra, variables can be set to just one of two values: true or false. Instead of using normal operators such as ×, -, + and ÷ Boole invented new ways of operating on variables with AND, OR and NOT. His work systematised Aristotle’s theory of logic and allowed logical arguments to be solved like mathematical equations.

So how did the work of a 19^{th} century self taught mathematician lead to today’s digital revolution?

Well, in the decades after Boole’s death, other mathematicians expanded on his work to develop the modern Boolean algebra we use today. And in the 1930s, Alan Turing demonstrated that it’s possible to solve any computable problem using Boolean algebra alone – which means he showed it’s possible to perform mathematics using just two values – 0 and 1 (or true and false).

This was groundbreaking as the smallest components of computer chips are essentially little switches that can be either off or on. In the right configuration, these switches can be used to perform Boolean algebra, and therefore mathematics.

In essence, Boolean algebra provides the link that maps the physical components of a computer – electricity flowing through millions of metal switches – to the logical and mathematical tasks we use computers to perform.

Sadly Boole’s devotion to his work led to his early death. After walking three miles in the pouring rain he delivered a lecture in wet clothes. Shortly after he contracted pneumonia and died shortly afterwards, aged just 49.

Characteristic for a self made man in the Victorian era, Boole was an active community campaigner on issues ranging from labour hours to prostitution. Boole was a progressive thinker in his personal life too. His wife, Mary Everest, was an independent thinker and mathematician in her own right, and their five daughters grew up to be mathematicians and novelists.

It’s amazing to think Boole could never have predicted the profound technological and social changes his algebra would enable – or that he would be most commonly remembered in the true/false variable type “bool” or “Boolean” found in nearly every computer programming language.