Edsger W. Dijkstra: Trending quotes (page 2)

“Simplicity is prerequisite for reliability.”

Edsger W. Dijkstra

1970s, How do we tell truths that might hurt? (1975)

“When we take the position that it is not only the programmer's responsibility to produce a correct program but also to demonstrate its correctness in a convincing manner, then the above remarks have a profound influence on the programmer's activity: the object he has to produce must be usefully structured.”

Edsger W. Dijkstra

Dijkstra (1970) " Notes On Structured Programming http://www.cs.utexas.edu/users/EWD/ewd02xx/EWD249.PDF" (EWD249), Section 3 ("On The Reliability of Mechanisms"), p. 6.
1970s

“We must not forget that it is not our [computing scientists'] business to make programs, it is our business to design classes of computations that will display a desired behaviour.”

Edsger W. Dijkstra

1970s, The Humble Programmer (1972)

Business , Forgetting

“How do we convince people that in programming simplicity and clarity —in short: what mathematicians call "elegance"— are not a dispensable luxury, but a crucial matter that decides between success and failure?”

Edsger W. Dijkstra

1980s
Source: EWD648.

People , Failure , Success

“There are very different programming styles. I tend to see them as Mozart versus Beethoven. When Mozart started to write, the composition was finished. He wrote the manuscript and it was 'aus einem Guss' (from one cast). In beautiful handwriting, too. Beethoven was a doubter and a struggler who started writing before he finished the composition and then glued corrections onto the page. In one place he did this nine times. When they peeled them, the last version proved identical to the first one.”

Edsger W. Dijkstra

Dijkstra (2001) Source: Denken als discipline https://www.youtube.com/watch?v=-Uae9_pgZzE#t=280, a program from Dutch public TV broadcaster VPRO from April 10th, 2001 about Dijkstra
2000s

Beauty , Time

“One moral of the above story is, of course, that we must be very careful when we give advice to younger people; sometimes they follow it!”

Edsger W. Dijkstra

Dijkstra (1972) The Humble Programmer http://www.cs.utexas.edu/users/EWD/transcriptions/EWD03xx/EWD340.html (EWD340).
1970s
Context: After having programmed for some three years, I had a discussion with A. van Wijngaarden, who was then my boss at the Mathematical Center in Amsterdam, a discussion for which I shall remain grateful to him as long as I live. The point was that I was supposed to study theoretical physics at the University of Leiden simultaneously, and as I found the two activities harder and harder to combine, I had to make up my mind, either to stop programming and become a real, respectable theoretical physicist, or to carry my study of physics to a formal completion only, with a minimum of effort, and to become....., yes what? A programmer? But was that a respectable profession? For after all, what was programming? Where was the sound body of knowledge that could support it as an intellectually respectable discipline? I remember quite vividly how I envied my hardware colleagues, who, when asked about their professional competence, could at least point out that they knew everything about vacuum tubes, amplifiers and the rest, whereas I felt that, when faced with that question, I would stand empty-handed. Full of misgivings I knocked on van Wijngaarden’s office door, asking him whether I could “speak to him for a moment”; when I left his office a number of hours later, I was another person. For after having listened to my problems patiently, he agreed that up till that moment there was not much of a programming discipline, but then he went on to explain quietly that automatic computers were here to stay, that we were just at the beginning and could not I be one of the persons called to make programming a respectable discipline in the years to come? This was a turning point in my life and I completed my study of physics formally as quickly as I could. One moral of the above story is, of course, that we must be very careful when we give advice to younger people; sometimes they follow it!

People

“Automatic computers have now been with us for a quarter of a century. They have had a great impact on our society in their capacity of tools, but in that capacity their influence will be but a ripple on the surface of our culture, compared with the much more profound influence they will have in their capacity of intellectual challenge without precedent in the cultural history of mankind.”

Edsger W. Dijkstra

Dijkstra (1972) The Humble Programmer http://www.cs.utexas.edu/users/EWD/transcriptions/EWD03xx/EWD340.html (EWD340).
1970s

History

“Besides a mathematical inclination, an exceptionally good mastery of one's native tongue is the most vital asset of a competent programmer.”

Edsger W. Dijkstra

1970s, How do we tell truths that might hurt? (1975)

Mathematics

“I think of the company advertising "Thought Processors" or the college pretending that learning BASIC suffices or at least helps, whereas the teaching of BASIC should be rated as a criminal offence: it mutilates the mind beyond recovery.”

Edsger W. Dijkstra

Dijkstra (1984) Source: The threats to computing science http://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/EWD898.html (EWD898).
1980s

Thinking , Learning , Help

“Testing shows the presence, not the absence of bugs”

Edsger W. Dijkstra

Dijkstra (1969) J.N. Buxton and B. Randell, eds, Software Engineering Techniques, April 1970, p. 16. Report on a conference sponsored by the NATO Science Committee, Rome, Italy, 27–31 October 1969. http://homepages.cs.ncl.ac.uk/brian.randell/NATO/nato1969.PDF Possibly the earliest documented use of the famous quote.
1960s

“In the good old days physicists repeated each other's experiments, just to be sure. Today they stick to FORTRAN, so that they can share each other's programs, bugs included.”

Edsger W. Dijkstra

1970s, How do we tell truths that might hurt? (1975)

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

Edsger W. Dijkstra

1970s, How do we tell truths that might hurt? (1975)

“As economics is known as "The Miserable Science", software engineering should be known as "The Doomed Discipline", doomed because it cannot even approach its goal since its goal is self-contradictory. (…) Software engineering has accepted as its charter "How to program if you cannot.”

Edsger W. Dijkstra

Dijkstra (1988) " On the cruelty of really teaching computing science http://www.cs.utexas.edu/users/EWD/transcriptions/EWD10xx/EWD1036.html (EWD1036).
1980s

Science

“About the use of language: it is impossible to sharpen a pencil with a blunt axe. It is equally vain to try to do it with ten blunt axes instead.”

Edsger W. Dijkstra

1970s, How do we tell truths that might hurt? (1975)

“As a result of a long sequence of coincidences I entered the programming profession officially on the first spring morning of 1952, and as far as I have been able to trace, I was the first Dutchman to do so in my country.”

Edsger W. Dijkstra

1970s, The Humble Programmer (1972)

Spring , Country

“Programming is one of the most difficult branches of applied mathematics; the poorer mathematicians had better remain pure mathematicians.”

Edsger W. Dijkstra

1970s, How do we tell truths that might hurt? (1975)

Mathematics

“What is the shortest way to travel from Rotterdam to Groningen, in general: from given city to given city. It is the algorithm for the shortest path, which I designed in about twenty minutes. One morning I was shopping in Amsterdam with my young fiancée, and tired, we sat down on the café terrace to drink a cup of coffee and I was just thinking about whether I could do this, and I then designed the algorithm for the shortest path. As I said, it was a twenty-minute invention. In fact, it was published in ’59, three years late. The publication is still readable, it is, in fact, quite nice. One of the reasons that it is so nice was that I designed it without pencil and paper. I learned later that one of the advantages of designing without pencil and paper is that you are almost forced to avoid all avoidable complexities. Eventually that algorithm became, to my great amazement, one of the cornerstones of my fame.”

Edsger W. Dijkstra

Dijkstra (2001), in an interview with Philip L. Frana. (OH 330; Communications of the ACM 53(8):41–47)
2000s

Way , Travel , Coffee , Drink

“Our intellectual powers are rather geared to master static relations and … our powers to visualize processes evolving in time are relatively poorly developed. For that reason we should do (as wise programmers aware of our limitations) our utmost to shorten the conceptual gap between the static program and the dynamic process, to make the correspondence between the program (spread out in text space) and the process (spread out in time) as trivial as possible.”

Edsger W. Dijkstra

Dijkstra (1968) " A Case against the GO TO Statement http://www.cs.utexas.edu/users/EWD/ewd02xx/EWD215.PDF" cited in: Bill Curtis (1981) Tutorial, human factors in software development. p. 109.
1960s

Time

“When I came back from Munich, it was September, and I was Professor of Mathematics at the Eindhoven University of Technology. Later I learned that I had been the Department's third choice, after two numerical analysts had turned the invitation down; the decision to invite me had not been an easy one, on the one hand because I had not really studied mathematics, and on the other hand because of my sandals, my beard and my "arrogance"”

Edsger W. Dijkstra

whatever that may be
Dijkstra (1993) "From my Life" http://www.cs.utexas.edu/users/EWD/transcriptions/EWD11xx/EWD1166.html (EWD 1166).
1990s

Mathematics , Decision , Study , Learning

“My point today is that, if we wish to count lines of code, we should not regard them as "lines produced" but as "lines spent": the current conventional wisdom is so foolish as to book that count on the wrong side of the ledger.”

Edsger W. Dijkstra

Dijkstra (1988) " On the cruelty of really teaching computing science http://www.cs.utexas.edu/users/EWD/transcriptions/EWD10xx/EWD1036.html (EWD1036).
1980s

Wisdom , Books