Spread your butter thin

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10 mei 2012 | David Harel feels “flattered, but embarrassed” that at the TU/e symposium his achievements are mentioned in one breath with those of Alan M. Turing, the most revered pioneer of computer science. 2012 is Turing Centennial Year during which scientists honor this visionary and how his work impacts future research.

In the context of the Turing Year 2012, Professor David Harelfrom the Weizmann Institute of Science in Rehovot (Israel) receivedan honorary doctorate from the Technical University Eindhoven.Renowned researcher and thinker in computer science, Harel inventedStatecharts, a computing language used broadly for thespecification and development of software and systems.

During his visit to the Netherlands he said to ScienceGuide thathe feels extremely grateful to receive an honorary doctorate fromthe University of Eindhoven, the place where many years ago Edsger Dijkstra achieved great advancements forcomputer science.

“His work here at this university was very important for ourdiscipline. In fact, I believe that the research he conducted rightat this spot was far more relevant than what he did in his lateryears at the University of Texas. He was a true pioneer, much moreso than I am. He is someone I really admire and in a way he is muchmore like Turing, a brilliant mind himself.”

Harel says that he was surprised how little Dijkstra’sachievements are known to the people in Eindhoven and theNetherlands. “I am amazed that the TU Eindhoven doesn’t publicizethis connection more. Dijkstra was a great inspiration and this issomething people need to be aware off. In contrast, I believe thatStanford puts a great effort in publicizing the fact thatartificial intelligence pioneer John McCarthy worked there.”

Not just a great scientist, but a visionary

For the occasion of Alan Turing’s 100th birthday TUEindhoven organized a symposium during which Harel received hishonorary doctorate. Regarding the symposium’s title ‘From Turing toHarel: Pioneers of Computer Science’, Harel had some reservations.”I actually found it embarrassing to be mentioned in one breathwith Turing. I wanted to change the title, but my appeal didn’twork. My contributions are much more modest. After all, I amstanding on the shoulders of Turing.”

To the question why he felt so embarrassed about this, Harel cutstraight to the point: “Alan Turing was much more than a greatscientist, he was a true visionary! I am convinced that for atleast another 30 years we will be busy trying to understand what hewanted to teach us.

His impact on the scientific community is tremendous, especiallygiven that he died at the age of 42, in the early 50’s, and forthat matter under scandalous circumstances. The name of Alan Turingwill go down in history alongside names like Einstein, Galileo, andDarwin. In a way, his impact on humanity is greater than that ofany of them.”

Harel continues explaining that Turing was not a classic naturalscientist. That is also the reason why he or any of his successorsin computer sciences would never receive a Nobel Prize. “For ourdiscipline this prize simply doesn’t exist. Instead, we inventedthe ‘Turing Award’, which Edsger Dijkstra, for instance, receivedlong ago for his work. This is a distinction of similar importanceas the Nobel Prize, even though people may not be aware ofthat.”

Tragic past

David Harel then talks with much empathy about Alan Turing’slife and the “outrageous” circumstances under which he died. Turingwas the first to theoretically conceptualize how a machine could bedesigned that would solve any computable problem. He also worked oncryptanalysis, and it was to a large extent Turing’s work thatenabled the British to decipher the codes of Enigma, the infamousNazi cryptography machine.

Even though this work was a great aid to the Allied war efforts,Turing received little praise afterwards. In the early 50’s Turingcommitted suicide following public prosecution due to hishomosexuality. “What happened to Alan Turing is outrageous. Theingratitude of British society is shameful and it is a terriblething that something like that would happen to a brilliant mindlike Turing.

It reminds me of Galileo’s fate who was stigmatized by thechurch when he postulated that the world was not at the center ofthe universe. The Turing Year is only a modest tribute to theachievements of this man, and especially given what he had toendure.

The world finally recognizes his meaning to scientific progress,and there are numerous symposia, conferences, gatherings and manyother activities worldwide to mark this special year; in Israeltoo. From my part, two of my expository books on the foundations ofcomputer science, in which Turing’s work is central, will come outthis year in new printings.” 

All in his head

David Harel summarizes Alan Turing’s contribution to computersciences in one sentence: “He made crystal clear the understandingof what can and cannot be computed.” According to Turing, allcomputer languages and systems are equivalent in what they are ableto compute.

“Whatever the largest, most complex supercomputer can do, anylaptop can do as well – it will only take more time and/or morememory, etc. This is a radical insight and an extremely robust onetoo. Alan Turing theorized this already in 1936, when no computerhad ever been built! He was able to establish this mathematically;it was simply in his head.”

This idea was so extraordinary because Turing’s theoreticalcomputer, later to be called fondly the Turing machine, wasuniversal. Based on this fundamental concept, the first computerswere designed which could then do any calculation you can thinkoff. John von Neumann took this elementary idea, and used it in thebasic design of the first ‘real’ computers.

“It is possible that one day we will be able to build largequantum computers and these will work differently from the ones wehave right now. Still, they will be only able to do exactly thesame things. They will probably be much, much faster, but they willnot be able to solve anything new.

This greater speed of calculation can be a very handy thing, butit still does not compare to Turing’s fundamental insight that allcomputers are equivalent.” Meanwhile, the possibility of creatingquantum computers itself has made a leap forward. Recently, a teamsurrounding Leo Kouwenhoven discovered the Majorana particle, which couldbe a major step towards realizing such a machine.

Modeling biological systems

Now imagine that Alan Turing would have had a better fate,growing old as a professor in his discipline, what could he havechanged for science? Harel: “It is very hard to tell. The onlything that I can predict is that he would no doubt have done a lotmore in the field of computational biology.

In his final years, he was particularly fascinated by thepossibility of constructing mathematical models that could analyzeand recreate biological patterns. I think that with his help wewould be 20 years ahead of where we are right now.” David Harelhimself has developed a similar passion in combining computerscience and biology. “Analyzing growth patterns in biology is avast research field. Just think about what we still have to learnabout biological process like how cancers come about andspread.”

For the future, Harel has a clear vision: “Computer science willbecome vital to the leading sciences of the 21st century, namelybiology, biochemistry and medicine. This compares to the importantthe role mathematics had for breakthroughs in physics in the20th century.” He forecasts that within 15 years abiologist will have to know almost as much about computer scienceas your typical computer scientist. Manipulating biochemicalprocesses with the help of complex algorithms will be fundamentalto 21st century sciences.

Where then will humanity be during the next Turing CentennialYear, 2112? What will science be like in 100 years from now? Harelbegins his answer with a quote: “You know there is an old Jewishsaying: ‘Prophecy is given to the fools’, which is why I am notgoing to try to predict what will happen in the future. But thereis something that I would really like to see. But before I begin toexplain, please take a moment and watch this video:


“What you are seeing is the embryo of aC. elegansworm that growsfrom a 2 cell organism to an almost mature creature. But this isonly the beginning. Within a couple of years we will be able tomodel biological growth processes in much greater detail. At somepoint, we will be able to digitally manipulate individualcharacteristics like a creature’s DNA. What starts with a simplesimulation of a maturing worm could lead to complete, manipulablecomputer models of human beings. This way we could decide how tobest detect and cure diseases simply by altering aspects ofrealistic computer models.”

Outside the lab thick skin needed

David Harel is not only active as a scientist, but has become afervent advocate of the Near East peace process. Together withother intellectuals he advocates for a diplomatic solution and afair retreat from most of the territories occupied by Israel in1967, a stance that is much disliked by Israel’s Prime MinisterNetanyahu. “Peace can only exist if both parties come to anagreement.

Recently, I have spent around 20% of my time trying to influencethe peace process in Israel. Within computer sciences, there is avery clear and clean way of thinking. Doing work for the public,especially in Israel, is much more frustrating and you needdifferent talents. Above all, what you need is thick skin. Manypeople will criticize you as arrogant when you try to use rationalarguments. What I am trying to do with my colleagues is to berealistic and to take some of the emotions out of the debate.”

“Our premise is that fear is one of the reasons that the peaceprocess is not moving forward. Israelis are afraid of Palestiniansplanning to drive them into the sea and Palestinians fear beingthrown out of the country and into Jordan. So we devised a pollwhere we asked our citizens whether they would support the peaceprocess if they became convinced that their fears wereungrounded.

Give Netanyahu the Nobel Prize

83% of all Israelis answered ‘Yes’; and even more surprisingly,76% of those who support Netanyahu’s right wing policies respondedwith ‘Yes’. What we really have to do, is finding a way toeliminate the fear on both sides of the border. Europe, PresidentObama and all the other parties involved can help with this bybuilding pressure.”

Not without irony, Harel then talks about a recent news articlehe wrote in the aftermath of an Israeli Chemist winning a Nobel.Harel asked in his article who would be the next Israeli in line toreceive this distinction in Stockholm. “I wrote that I do in factknow someone who would very well deserve this award. The only thinghe would have to do for this is to be bold.

I pray that Benjamin Netanyahu will be the next Nobel laureate.For this to happen, he would really have to do something courageousand bold, just like De Gaulle or Churchill. I do not have to agreewith what a politician like Netanyahu stands for, but the day hereceives the Nobel Prize I will tip my hat to him and celebrate himas a hero.”

Irresponsible scientist

Scientists have the great responsibility to advance our worldwith their thoughts, and this is also a maxim David Harel lives by.But one of the things that fascinate him about Alan Turing is thathe showed that working in many areas can be fruitful too. Harel cantell enthusiastic stories of how it should actually be possibly toexperience the smell of herbs and flowers when you view a video ofa market in the French Provence.

“I know, this says much about me spreading my interests in anirresponsible fashion. Often I hear from others that I ‘spread mybutter thin’. But this is the price I need to pay, just like AlanTuring did. Of course it can be very productive to focus all yourattention on one great project. The only problem is that I amafraid that if I did so I might die of boredom.”

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