George Boole is one of Ireland’s greatest scientists. His work fell out of fashion in the decades following his death in 1864, but today it is more relevant than ever. That is because Boolean algebra, as it is called, forms the basis of the way all digital computers work.
Boole was born in Lincoln in England in 1815 and he was a very bright child. He became a teacher when he was still in his teens and when he was 20 he opened his own school. At 34, he came to Ireland to become the first professor of mathematics at Queen’s College, Cork (now University College Cork) and he remained in this job until his death.
Boole believed that logic was more closely related to algebra than to philosophy, as was traditionally thought. He expressed this idea in a number of essays in the mid-19th century, culminating in “An Investigation into the Laws of Thought, on Which Are Founded the Mathematical Theories of Logic and Probabilities”.
George Boole, considered the father of computer science
Symbols
Boole noticed the similarity between the symbols used in algebra, like x and +, and those used in logical statements, like AND and OR.
Boole’s great achievement was his use of algebra to express logical propositions. Here is an example of that process, using Boole’s idea that the symbols of algebra and those of logical statements are interchangeable.
Take the following two statements:
A is all new cars
B is all red cars
Then combine them, using x instead of AND, and + instead of OR.
So, A+B is all cars that are either new OR red, and AB (or A times B) is all cars that are both new AND red.
Computers
Boolean algebra can describe many functions other than the two (AND and OR) used in this example. Most importantly, it still works when the variable in a statement is not a quantity, as in normal algebra, but a true or false statement.
As you may well know, computers use the base-two or “binary” number system. This means that at their most basic level they use only two values, zero and one.
To put it differently, everything a computer does boils down to a simple true or false decision. A computer’s circuitry then builds everything else on the basis of these values. Another way of looking at it is that a circuit is either on (one) or off (zero).
Search engines
When you search for something on the Internet using a search engine, you can use Boolean operators to narrow your search. These are things like AND and OR (as in the example above), and also NOT.
Search engines use Boole’s methods of expressing logical propositions to help you find information on the Web. You can test this out:
First search for “Boole” on a search engine and check the number of results
Then search for “Boole AND Cork” to get pages that mention both
Use “Boole NOT algebra” to find pages that mention him but not his work
So, learning more about George Boole is one practical way to make use of his algebra.
Learn More:
Learn more about Boole’s life and work
William Reville’s essay on George Boole
Find out more about Boolean Logic
