WHAT'S A PERSON: THE LIFE AND LEGACY OF ALAN TURING

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Summary

Alan Turing is often considered the father of computer science. He is well known for the "Turing Test", a method of assessing whether or not a computer is "intelligent". He also defined a category of computers, now called "Universal Turing Machines", which are capable of running any program that any of the others can run, given enough memory and time. He is less well known for a significant contribution to defeating Hitler by designing a device which could decode messages sent with the German "enigma" encryption machine. Despite his evident extreme value to Britain and to humanity, he was prosecuted for homosexuality, sentenced to "chemical castration" which also caused severe psychological side effects, and died of an overdose of cyanide. In 2009 the British government came to its senses and issued a posthumous apology and, just a few days ago, a pardon. I believe that Alan Turing's work points to the conclusion that all people, and other intelligent creatures and devices, are capable of thinking the same thoughts and learning the same knowledge, limited only by their memory and time.

Message

Our first Unitarian Universalist principle, which you can read on the back of our Order of Service, says "We affirm and promote the inherent worth and dignity of every person." Similarly, a clause in the Declaration of Independence of the United States says "We hold these truths to be self-evident, that all men are created equal." This principle of the Declaration of Independence was eventually incorporated into the Constitution of the United States in 1869, when the Fourteenth Amendment included the clause, "No state shall ... deny to any person within its jurisdiction the equal protection of the laws."

But, hopefully, it is not the words to which we adhere, but the meaning. There has been a long struggle within this nation, and within many nations and cultures, on the meaning of "person". We are currently struggling to live up to the commitment that ethnic minorities will be treated equally as people. The balance is tipping in favor of treating homosexuals equally in regard to marriage. We have ahead of us the question of proper treatment of people not in full compliance with out immigration laws, and other nations also have divisive immigration issues.

In the musical play 1776, book by Peter Stone in 1969, there is an example of how an apparently simple statement of ideals can be subverted. This play is a carefully researched, but musical and often comic, story of the adoption of the U.S. Declaration of Independence. Toward the end of the play a delegate notices that Thomas Jefferson has included in his draft a complaint that the King of England has induced them to adopt slavery. The delegate explains, "They are not people --- they are property", the anti-slavery clause is removed from the Declaration, and the bold statement that "all men are created equal" is implicitly interpreted to exclude black slaves. I should point out that the musical play ascribes this line to delegate Edward Rutledge of South Carolina. There is no evidence of the actual debate or Rutledge's position, but we do know that the paragraph was removed, and neither black slaves nor native Americans were legally considered people until after the Civil War. In fact, to this day, the concept that property rights override human rights is politically potent.

We Unitarian Universalists believe in an inclusive concept of person. We further believe, not just in granting the terminology "person", but also in the concepts expressed in our second, fifth and sixth principles, specifically: "justice, equity, and compassion in human relations; the right of the conscience and the use of the democratic process; and the goal of world community with peace, liberty, and justice for all."

In advocating for an inclusive concept of personhood, applicable throughout human relations, I believe it is advantageous to base ourselves, as much as possible, on the "free and responsible search for truth and meaning", which is our fourth principle. Such a scientific basis for defining "person" can be found in a source which would surprise many people, namely the life and work of a mathematician, namely Alan Turing.

As I recall, my own first encounter with the name "Turing" was with the "Turing test". This was proposed in 1950 in Turing's paper on "Computing Machinery and Intelligence" which opens with the words: "I propose to consider the question, 'Can machines think?'" We still do not know the answer to this question, but Turing proposed we approach it with a test based on communications. In such a test a person interacts with, and asks questions of, another person and a computer, with obvious clues of humanness excluded, i.e., the people cannot see each other, their words are converted to text for transmission, etc. If the interrogator cannot reliably tell which of them is the computer, then the computer is deemed intelligent.

In the 1980s, as personal computers were coming on the market, I took my daughter to a computer fair. There were some examples of programs aimed at passing the Turing test. They were pretty easy to distinguish from people. The better ones tended to sound like psychiatrists, always asking questions based on the last thing you typed. More recently a version of the Turing test has become a pervasive component of computer security. This is the CAPTCHA, which stands for "Completely Automated Public Turing-test to tell Computers and Humans Apart". Many web sites use this to determine whether a user is a person or another computer, by displaying a distorted image and asking the user to type it back.

Turing himself became involved in an endeavor curiously related to his test. He and a friend wrote a computer program to play chess, which was considered a game heavily involving human intellect. This was before the modern wave of electronic advances, and they had no computer to run the program. Turing himself simulated the computer, by playing a game of chess according to the procedures in the program. This experiment mostly proved that both his chess skills and the state of the art in computer hardware could be greatly improved. A few years ago the efforts of many other programmers finally resulted in a computer which could beat the world champion chess player. Nevertheless, full computer intelligence has not yet definitely arrived.

Though I am educated as a physicist, not a computer scientist, my work has involved much computer programming, so I have read many computer manuals and text books on computer programming. My second encounter with the name "Turing" was with the concept of a "Turing machine". A Turing machine is, essentially, a computer reduced to its bare essentials. The concept was introduced by Turing in a paper submitted in 1936 to the London Mathematical Society, but not published until 1937. The "automatic machine" as Turing himself called it had a single strip or tape of memory, and a processor which could look at only one symbol on that tape at a time. Nevertheless, Turing showed that some such machines, with a sophisticated enough procedure, could perform any process that any of the other machines could. These are now called "Universal Turing Machines". A modern computer, with many memory devices and a complex processor, can still not calculate any results, or perform any processes, except those which a Universal Turing Machine could. These conceptual devices are still used both in teaching about computing and in the highest-level study of what computers can and cannot do, and how efficiently they can solve various problems.

Our Worship Associate today, Reverend Barbara Meyers, is in fact a properly educated computer scientist, and she informs me that the UCLA computer science department's intramural team was called "The Turing Machines".

From neither of these products of Alan Turing's genius did I guess what I would next learn about him. A few years ago I received a gift from a friend, a book called The Code Book by Simon Singh. It is subtitled "The Secret History of Codes & Code-breaking" and one review calls it "a fascinating meander through the centuries, replete with tales of intrigue, political chicanery, military secrecy and academic rivalry." It included several pages on Turing, from conception to death, and eventual legacy.

Alan was conceived in Chatrapur, India to British parents, but they returned to Britain for his birth in 1912. Alan was then left in the care of nannies and friends till old enough to attend a boarding school. At school he was shy and awkward, his only skill being in science. At age 14 he met his true love, a fellow student with a gift for science named Christopher Morcom. Four years later Christopher died of tuberculosis. Later, at Cambridge, Alan kept a picture of Christopher on his table, "encouraging me to work hard."

Alan studied at Cambridge during a time of crisis in the philosophy of mathematics, and among the luminaries there at the time were Bertrand Russell, Alfred North Whitehead and Ludwig Wittgenstein. Whitehead had been Russell's thesis advisor, and together they had brought classical mathematics to its pinnacle with Principia Mathematica, published in three volumes, 1910, 1912 and 1913. Russell would later receive the Nobel literature prize, and write one of my favorite books, History of Western Philosophy. Whitehead went on to develop "process philosophy". One of his students was a Unitarian Universalist named Charles Hartshorne who developed it into "process theology".

With Principia Mathematica the mathematics community believed they had finally eliminated paradox, from the paradoxes first discovered by the ancient Greeks, to one recently identified by Russell himself. Two and half thousand years of careful thinking by the finest minds had finally brought the intellectual elite to the promised land.

But the euphoria had been shattered in 1931 when the Austrian mathematician Kurt Friedrich Gödel published a paper entitled "On Formally Undecidable Propositions of 'Principia Mathematica' and Related Systems". He had discovered not just a minor error in Principia, or even a new paradox to be resolved, but a fundamental limit to mathematics. Any system of mathematical logic, if sufficiently advanced to include ordinary arithmetic, and if free from contradictions, would leave some true equations unprovable.

Mathematicians were now wondering whether these true-but-unprovable statements were merely some esoteric theorems of no practical import, or if they perhaps included some important formulas essential to science. Alan Turing was among many who attacked this problem. From considering what, exactly, was the process of arithmetic and calculation, he came up with his definition of automatic machines. Amazingly to me, and I think to many, an abstruse endeavor understood by at most a few extreme intellectuals was now on its way to advancing the development of a device - the computer - which has now, in many disguises such as smart phones become the closest associate of probably over half the world's population. My two-year-old granddaughter picks up rectangular blocks and walks around holding them like a cellphone, with her thumbs in place to type text messages on her imaginary keys.

But a much more urgent problem was now imposing itself on the world: Adolf Hitler and Nazism. Even mathematicians were needed in this struggle against evil. The Germans were developing war tactics which involved quick, secret communication. On land and in the air the "blitzkrieg" involved coordinated action so fast the enemy could not plan a defense. Underwater the u-boats were to gather around targets, but none were to attack until all were ready. To support this, a complex mechanical encoder had been developed called the "enigma machine". This device provided for use of ten quadrillian different keywords. The Germans distributed a book of day keys, each of which was used to encode individual keywords for each message sent that day.

In 1932 a Polish mathematician, Marian Rejewski, from just a general description of the enigma, had accomplished the amazing feat of decoding its messages. For six years the Polish government was privy to secret German military messages. But in 1938 the Germans significantly increased the complexity of the enigma, and the flow of information stopped. The next year the Nazis quickly overran Poland, but Rejewski and a few associates escaped to France. Then they escaped again to England, arranging the smuggling of a captured enigma to England in the luggage of a theatre director and his actress-wife. Alan Turing and a few others were now given the task of decoding the new-and-improved enigma's messages.

Turing solved the problem mathematically, and designed a machine to reverse the enigma's codes. The first of these was delivered early in 1940, but was far too slow. He designed a faster version which arrived and was put into operation on August 8, while the air war was heating up over Britain. Among the first messages decoded was one stating Hitler's directive of July 16 that the British Royal Air Force was to be destroyed prior to an invasion. Direct communication was established with Air Chief Marshall Stuffy Dowding. When direct attacks on British airfields began on August 23, Stuffy and Air Vice Marshall Keith Rodney Park were able to combine decoded German messages with radar images and lookout sightings to organize and command the British defense. The Battle culminated on October 15 when essentially the entire German Luftwaffe was sent in two waves against London and southeast Britain. The British Air Force did its job and two days later Hitler had to call off the invasion, his first military setback.

Details of the mathematics used by Rejewski and Turing to unlock enigma are given in The Code Book, mentioned earlier. It was absolutely not easy. The very best mathematicians available were set to the task. These two were truly brilliant.

After the war Turing produced the first detailed design of a stored-program computer. In 1948 he was appointed to the math department of the University of Manchester and became Deputy Director of its computing laboratory. This was where he developed the Turing test.

In 1952 Turing's house was burgled by an acquaintance of Turing's gay lover. In reporting the crime, that relationship was mentioned and the two of them were arrested. He was convicted of "gross indecency", the legal code-word for a homosexual act, and given a choice of prison or chemical castration. He chose the latter, which led to serious psychological side-effects, including depression. On June 8 of 1954 he acted out a scene from his favorite movie, Disney's Snow White, eating from a cyanide laced apple, and died.

What a way to treat the person to whom so many owed so much!

Since then many have done better for Turing's memory. In 1966 the Association for Computing Machinery established the Turing Award, considered the highest distinction in computer science. In 1999 Time Magazine included him in the list of the one hundred most important people of the twentieth century. The city of Manchester has honored him in a number of ways, including a statue of him sitting on a bench. In front of this statue, on Turing's one hundredth birthday, the Olympic torch was passed on its way to London. This is the picture on the front of today's Order of Service.

But my purpose today is to learn from Turing's life and work, not his death. Considering my initial question, "What's a person?" I believe we can find two very important ingredients of the answer in Turing's writings.

The first of these is the Turing test, especially its emphasize on communication as a means of testing intelligence. All human beings have language. Even a deaf-mute such as Helen Keller could be taught to communicate. Through communication we can learn that all human beings are persons, regardless of their race, or condition of servitude, or even sexual practices. I think we must now also begin to seriously consider the possibility that some non-human animals should be considered persons. We have engaged in extensive communication with chimpanzees and gorillas and are beginning to have success with dolphins and others. I might even bring forward our dog Wally, now deceased, who could clearly tell when we were talking of going for a walk, apparently even when we spelled the critical word, and always told us whether the person at the front door was friend or newcomer.

Secondly, I would cite the concept of a Universal Turing Machine, and the various theorems which Turing and others have proved regarding them. Anything which can be calculated by one of them can also be calculated by any other. While they can be built of anything from legos to levers or vacuum tubes to transistors, their abilities depend only on their speed and the size of their memories. So too I believe that all persons are capable of the same thoughts and understanding. We may differ in learning speed and in how much we know, but not in the sorts of things we can know. We are all equal in this last regard.

I believe we can and should claim that our inclusive concept of personhood is firmly based in science.

For example, undocumented aliens are persons, and entitled to fair treatment as required by the Fourteenth Amendment to the United States Constitution. Quoting again, from the play 1776, John Adams - meaning the character in the play since we have no transcript of the Continental Congress - responding to the complaint that he called black slaves "Americans", proclaims "They're people and they're here -- if there is any other requirement I've never heard of it."

Finally, in this past week a notable event has occurred. It turns out to be very appropriate that this sermon topic is occurring on this Sunday. For some years a coalition of computer scientists, gay-rights advocates, and others, including Stephen Hawking, has been pressing the British government in regard to Turing's conviction. In 2009 Prime Minister Gordon Brown issued an apology, but a bill pardoning him stalled in Parliament. However, five days ago, on Christmas Eve, at the request of Justice Minister Chris Grayling, Her Majesty Queen Elizabeth II signed a royal prerogative of mercy, pardoning him immediately.