The other day, I stumbled upon the Memorial Resolution about Edgar Wybe Dijkstra, whom you may have known as the creator of the now-famous Dijkstra shortest path algorithm. Dijkstra was a professor at the Eindhoven University of Technology, and later at University of Texas at Austin (1984 – 2002). He was the winner of 1972’s ACM Turing Award, the “Nobel prize of computer science”. The full text of the Memorial Resolution containing a short but very interesting and inspiring biography of his life can be accessed at: http://www.utexas.edu/faculty/council/2002-2003/memorials/Dijkstra/dijkstra.html. I just want to quote some of the things there which I really found inspiring.

On his project of “Streamlining Mathematical Arguments”, he said:

“As a matter of fact, the challenges of designing high-quality programs and of designing high-quality proofs are very similar, so similar that I am no longer able to distinguish between the two: I see no meaningful difference between programming methodology and mathematical methodology in general. The long and short of it is that the computer’s ubiquity has made the ability to apply mathematical method[s] more important than ever.”

On teaching formal methods (which was considered radical novelties) in the university, he said:

“Teaching to unsuspecting youngsters the effective use of formal methods is one of the joys of life because it is so extremely rewarding. Within a few months, they find their way in a new world with a justified degree of confidence that is radically novel for them; within a few months, their concept of intellectual culture has acquired a radically novel dimension. To my taste and style that is what education is about. Universities should not be afraid of teaching radical novelties; on the contrary, it is their calling to welcome the opportunity to do so. Their willingness to do so is our main safeguard against dictatorships, be they of the proletariat, of the scientific establishment, or of the corporate elite.”

He consider creating a teachable material must be one of the main objectives of a research:

“For me, the first challenge for computing science is to discover how to maintain order in a finite, but very large, discrete universe that is intricately intertwined. And a second, but not less important challenge is how to mould what you have achieved in solving the first problem, into a teachable discipline: it does not suffice to hone your own intellect (that will join you in your grave), you must teach others how to hone theirs. The more you concentrate on these two challenges, the clearer you will see that they are only two sides of the same coin: teaching yourself is discovering what is teachable.”

An interesting fact about him:

Dijkstra enjoyed the natural beauty of Austin and the surrounding hill country. He and his wife had a fondness for exploring state and national parks in their Volkswagen bus, dubbed the Touring Machine, in which he wrote many of his technical papers. They had a constant stream of visitors in their home, for whom he enjoyed playing Mozart on his Bösendorfer piano.

The introduction given for his 1972’s ACM Turing Award:

The working vocabulary of programmers is studded with words originated or forcefully promulgated by E. W. Dijkstra: display, deadly embrace, semaphore, go-to-less programming, structured programming. But his influence on programming is more pervasive than any glossary can possibly indicate. The precious gift that this Turing Award acknowledges is Dijkstra’s style: his approach to programming as a high, intellectual challenge; his eloquent insistence and practical demonstration that programs should be composed correctly, not just debugged into correctness; and his illuminating perception of problems at the foundations of program design. He has published about a dozen papers, both technical and reflective, among which are especially to be noted his philosophical address at IFIP, his already classic papers on cooperating sequential processes, and his memorable indictment of the go-to statement. An influential series of letters by Dijkstra have recently surfaced as a polished monograph on the art of composing programs. We have come to value good programs in much the same way as we value good literature. And at the center of this movement, creating and reflecting patterns no less beautiful than useful, stands E. W. Dijkstra.

His thought about communication problems through writing:

At a given moment, the concept of polite mathematics emerged, the underlying idea of which is that, even if you have only 60 readers, it pays to spend an hour if by doing so you can save your average reader a minute. By inventing an idealized “average reader”, we could translate most of the lofty human goal of politeness into more or less formal criteria we could apply to our texts.

Other quotes from him:

Computer Science is no more about computers than astronomy is about telescopes.

A formula is worth a thousand pictures.

Always design your programs as a member of a whole family of programs, including those that are likely to succeed it.

Separate Concerns.

A Programming Language is a tool that has profound influence on our thinking habits.

The competent programmer is fully aware of the strictly limited size of his own skill; therefore he approaches the programming task in full humility, and among other things he avoids clever tricks like the plague.

Progress is possible only if we train ourselves to think about programs without thinking of them as pieces of executable code.

Program testing can at best show the presence of errors but never their absence.

… if 10 years from now, when you are doing something quick and dirty, you suddenly visualize that I am looking over your shoulders and say to yourself, Dijkstra would not have liked this, well that would be enough immortality for me.

As a matter of fact the still often repeated requirement that axioms should be self evident strikes me as a medieval relic: to the extent that they take philosophy seriously, it is impossible for me to take logicians seriously. (Again this may be a cultural difference: it seems there are societies in which philosophers still have some intellectual standing.)

The use of COBOL cripples the mind; its teaching should, therefore, be regarded as a criminal offense.

Being abstract is something profoundly different from being vague.

The problems of the real world are those that remain when you ignore their known solutions.

The prisoner falls in love with his chains. (In reference to programmers using inadequate tools.)

I pray daily that more of my fellow programmers may find the means of freeing themselves from the curse of compatibility.

Brainpower is by far our scarcest resource.

My daughter and I taking a shower with equal frequency is a frightening thought for both of us. (February 21,1984; commenting on a mutual exclusion algorithm in which the two components are alternately granted access to the critical section.)

Nothing is as expensive as making mistakes.

If you carefully read its literature and analyze what its devotees actually do, you will discover that software engineering has accepted as its charter, “How to program if you cannot.”

We must give industry not what it wants, but what it needs.

Waiting is a very funny activity: you can’t wait twice as fast.

Do not try to change the world. Give the world the opportunity to change itself.

So-called natural language is wonderful for the purposes it was created for, such as to be rude in, to tell jokes in, to cheat or to make love in (and Theorists of Literary Criticism can even be content-free in it), but it is hopelessly inadequate when we have to deal unambiguously with situations of great intricacy, situations which unavoidably arise in such activities as legislation, arbitration, mathematics or programming. (Foreword to Teaching and Learning Formal Methods, edited by C. N. Dean and M. G. Hinchey, Academic Press, 1996.)

The traditional mathematician recognizes and appreciates mathematical elegance when he sees it. I propose to go one step further, and to consider elegance an essential ingredient of mathematics: if it is clumsy, it is not mathematics.

Don’t compete with me: firstly, I have more experience, and secondly, I have chosen the weapons. (During first lecture in Capita Selecta, August 29, 1996.)

Maintaining a large range of agilities mental and physical requires regular exercise […]. That is why the capable are always busy. (Lecture, Capita Selecta, October 10, 1996.)

Mathematicians are like managers; they want improvement without change. (During a meeting of the Austin Tuesday Afternoon Club, Fall 1996.)

… I had already come to the conclusion that in the practice of computing, where we have so much latitude for making a mess of it, mathematical elegance is not a dispensable luxury, but a matter of life and death.