Who is Alan Turing and Why is Turing Important?
Alan Turing can be considered “the father of computer science and AI.” Turing made significant contributions to computing, codebreaking, and even helped the Allies win WWII. Specifically, he gets the title “the father of computer science and Artificial Intelligence” from his early work where he illustrated the concept of AI and programmable digital computers before either existed.
Below we give an overview of Turing the genius, Turing the war hero, and Turing the eventual victim of state-sponsored LGBT discrimination. There are many reasons to consider Alan Turing the father of Computer Science and Artificial Intelligence (AI), from his theoretical work, to his help building computing device in WWII, to his work on one of the first videos games toward the end of his life. With that in mind, let us start with an overview of Turing’s major inventions and contributions to science.
What Did Alan Turing Invent?
Turing, often with the help of others, invented or helped develop:
- The concept of Artificial intelligence. In his famous 1950 paper.
- The concept of a programable digital computer with his Turing Machines (which build on Babbage’s theoretical machines). Which he introduced in 1936.
- The Manchester Mark 1. One of the first computers. Created in 1948.
- The Bombe, an early computer that cracked Germany’s Enigma codes during WWII (based on a Polish device, the Bomba). Breaking the Enigma code is thought to have shortened the war with Germany by years and saved millions of lives. Developed in 1939.
- Turochamp. One of the first video games, a version of chess that began production in the 1940’s.
- And much more.
Alan Turing – Celebrating the life of a genius. This video by Numberphile sums up Turing nicely.
TIP: Alan Turing is famous for his theoretical and real computers. To understand why that is important, we have to understand what the heck a theoretical computer is.
What is a Theoretical Computer?
A theoretical computer is a computer mapped out on paper rather than built in real life. 
Before we could build modern computers (or at least before anyone would fund their creation), they were imagined by the minds of great mathematicians. These men and women explored on paper what would later be accomplished with electronics. Although analog computers, such as the Antikythera Mechanism, have existed since at least 200 BC theoretical computers weren’t devised until the 1830’s. Charles Babbage conceptualized the first theoretical computer in the 1830’s, Ada Lovelace wrote the first advanced bit of code a few years later, and then 100 years later Turning built on their work with his own unique Turing Machines (which later became the foundation for the first electronic computers).
FACT: Today we still build theoretical computers to explore computer science that is beyond the realm of current computing. For instance, we might theorize how quantum computers can solve codes even though current quantum computers are in a stage of cryptography infancy.
Intro to Theoretical Computer Science. I don’t suggest trying to understand complexity theory and theoretical computers in-depth unless you have a background in the subject (although this video course is a great choice). That said, this video is a quick introduction to the concept of theoretical computers.
Why Was Alan Turning’s Theoretical Computer Special?
Charles Babbage showed us that computers could theoretically calculate numbers with his Difference Engines and Analytical Engine. Ada Lovelace showed us that Babbage’s machines could theoretically compute more than just numbers. Alan Turing showed us that we could theoretically create a machine that could think like a human, which he demonstrated by his “Turing Machines” and his pioneering work in AI including his Imitation Game, explained below.
“Let us return for a moment to Lady Lovelace’s objection, which stated that the machine can only do what we tell it to do…” – Alan Turing
Turing machines are logic-based computing devices with unlimited storage space that were built with mathematical rule-sets and a strip of tape. Expanding on the work of Babbage and other predecessors, Turing invented the first Turing machine in 1936. Many similar machines followed. They can’t accurately be summed up without dedicating more space to the venture than we have here. See Turing Machines example or watch the video below for more information. 
TIP: A Universal Turing Machine (UTM, or simply a universal machine) is a Turing machine that can simulate other Turing machines. For this reason, it is the one people typically talk about. Machines like the UTM are only part of what given Alan Turing the title of “father of modern computer science”.
“I’m building a brain; a system so advanced it can calculate entire mathematical scenarios for researchers, rather than aid with the odd equation.” – Alan Mathison Turing (paraphrasing)
TIP: A Turing machine is an example of machine automata. A neat and straightforward example of automata is Conway’s Game of Life.
Turing’s Enigma Problem
Turing worked for the British Government before and during WWII, specifically regarding code breaking (something that is very similar to building theoretical computers, and computing itself). The Germans’ “Enigma Machine” turned the tide of the war in Germany’s favor by giving them the ability to communicate their daily plans as encrypted messages using principles of cryptography. After an uncomfortably long time, Mr. Turing turned one of his theoretical computers into a real computer, building one of the first modern computers (the Bombe), cracking the Enigma code, and turning the tide of WWII.
The Teams that Cracked the Code
Turing lead the team that designed the Bombe at the Government Code and Cypher School (GC&CS) at Bletchley Park, Britain’s codebreaking center. “Important refinements were made in 1940 by Gordon Welchman and the engineering design and construction was the work of Harold Keen of the British Tabulating Machine Company. The Bombe itself was a substantial development from a device invented in 1938 in Poland known as the “cryptologic bomb” (Polish: bomba kryptologiczna).” – The real story of the Bombe. 
The mechanics of the Enigma machine and the Bombe are summed up well by the following video:
Turing’s Enigma Problem (Part 1) – Computerphile.
MYTH: A quote that claimed Winston Churchill said, “Alan Turing made the single greatest contribution to the Allied victory in World War II” was never said, at least on record. If it were, it wouldn’t be too far from the truth. Cracking the German’s Enigma code probably did shorten the war with Germany by years, you can read about that here). As with computing, there is more to winning the war than one person, regardless of how important that person was. 
The Turing Test – Alan Turing’s Imitation Game
Toward the end of his life, Turing developed the Turing Test (AKA the imitation game). It was a general test of a machine’s ability to exhibit intelligent behavior equivalent to, or indistinguishable from, that of a human. This test was a precursor to our current cognitive computing and AI. Like all Turing related ideas, it is too complicated to sum up in a quick overview like this. You can learn more about the Turing Test (the Imitation Game) here.
In short, the Turing Test and Alan’s earlier work on theoretical computing and AI make him “the father of artificial intelligence”. He was the first one to assert that computers could think like humans (this same line of thinking is used in Google’s Deep Mind and IBM’s Watson).
“A computer would deserve to be called intelligent if it could deceive a human into believing that it was human.” – Alan Turing
Alan Turing and The Imitation Game. The SciShow explains the Imitation Game.
Turochamp – One of the First Video Games and the Birth of Video Game AI
Turing created many exciting things, but Turochamp (his only partially realized Chess game) can be considered one of the first video games. Importantly, the AI he constructed for the game was far beyond what was being created at the time (consider the other first game is tic-tac-toe, so, to frame this, Alan is working on chess while others are struggling with tic-tac-toe). 
THOUGHT: We can very nearly call Alan Turing “the father of video games” as well.
Turing – Building the First Modern Computers – The Manchester Mark 1
Aside the above, Turing also helped to create some of the first known computers including the Manchester Mark 1. With the Manchester, he applied his ideas to his “universal computing machine” to electronic computers.
“During the 1940s, Turing and others such as Konrad Zuse developed the idea of using the computer’s memory to hold both the program and data.” Using memory was a significant improvement over using tape. The mathematician John von Neumann was widely credited with defining the stored-program computer architecture employed by the Manchester Mark 1.
When we consider the Bombe, the Imitation game, the UTM, and the Manchester Mark 1 together, Alan earns his title of “father of computer science”. Of course, to be accurate, we would want to quickly mention Babbage, Lovelace, and the countless other greats whose names we don’t always remember.
Manchester Baby: world’s first stored program computer.
“Sometimes it is the people no one can imagine anything of who do the things no one can imagine.” – Alan Turing
A Sad Ending – Turing, LGBT, and the Poison Apple
Sadly, Turing only had a few short years to enjoy his life as a pioneer of electronic computers following WWII.
In 1952, Alan Turing became the victim of British legal system’s discriminatory policies at the time. He was charged with “gross indecency under Section 11 of the Criminal Law Amendment Act 1885“.  Sexual relations between members of the same sex were illegal in Britain until 1967 (and weren’t fully decriminalized in the UK until 1987). 
As punishment for his homosexuality, Turing had to choose between state-mandated chemical castration or prison. He chose castration, and that experience seemed to lead to his depression and eventual suicide by cyanide-laced poison apple. Although foul play was suspected, the official ruling on Turing’s death is suicide. 
In 2013, Turing was granted a rare mercy pardon by Queen Elizabeth over half a century after his death, although other individuals convicted of the same “crime” did not receive pardons. Mr. Turing’s role in WWII wasn’t well known until after his death. 
FACT: Alan Turing’s childhood friend, and crush, was a boy named Cristopher, who died while they were still in high-school. Christopher inspired his future work. In many ways, Turing’s interest in building AI can be traced directly to this relationship.
FACT: Alan Turing died by biting into a poison apple. Was this why Steve Jobs created the rainbow apple logo with a bite taken out of it? Or, was Jobs playing off of the Beatle’s record label Apple (the sosumi, aka so sue me, alert sound for OS 7 gives us a hint)? Was it a throwback to Newton or the Garden of Eden? Probably a little bit of all these things, Jobs was a rather calculated mastermind, just like Turing, Lennon, and Newton. The common thread is the analogy between the democratization of wisdom, the tree of life, and the advancement of civilization. This is something, cognizant of the theme or not, we owe to all these greats.
Was Alan Turing a Lone Genius?
Like most other important figures in history, Turing was individually brilliant but hardly worked alone. There were a few other greats in early theoretical computing like Babbage and Lovelace, who worked on theoretical computers 100 years before Turing). Other code breakers at Bletchley Park helped break the German’s codes. Many great men and women who worked with Turing in his time still work on his ideas today, as do many more contemporary figures.
With the many known and unknown heroes acknowledged, it is hard to talk about the theory involved in developing computers, AI, modern computing, cryptography, or winning World War II without talking about Turing and his many groundbreaking ideas.
Was Turing Really “The Father of Computer Science?”
We can consider Turing “the father of computer science”, but the title is a bit semantic with any “father of title” due to the complexities of humans and their inventions. It is also accurate to say that Alan Turing is the “father of modern computing and AI” or “father of theoretical computing and AI”, in all cases we are just expressing his pioneering and visionary in the computer sciences.
Alan Turing was, in ways, the Einstein of computing. However, just as Einstein didn’t single-handedly discover relativity, there is more to computer history and modern computing than Turing.
Turing is the father of computing in the way that Ada Lovelace was the first programmer or that Woz and Jobs invented the modern home computer. In the end, Alan Turing was much more than just a father of computing and is only one of many who deserve honorable mention. See multiple discovery theory.
Below is the story of Alan Turing from the BBC.
Alan Turing – BBC Horizon Documentary.