Edsger Dijkstra
Computer science is no more about computers than astronomy is about telescopes.Collection: Science
Elegance is not a dispensable luxury but a factor that decides between success and failure.Collection: Success
The question of whether a computer can think is no more interesting than the question of whether a submarine can swim.Collection: Computers
APL is a mistake, carried through to perfection. It is the language of the future for the programming techniques of the past: it creates a new generation of coding bums.Collection: Future
It is practically impossible to teach good programming to students that have had a prior exposure to BASIC: as potential programmers they are mentally mutilated beyond hope of regeneration.Collection: Hope
Don't compete with me: firstly, I have more experience, and secondly, I have chosen the weapons.Collection: Experience
Why has elegance found so little following? That is the reality of it. Elegance has the disadvantage, if that's what it is, that hard work is needed to achieve it and a good education to appreciate it.Collection: Education
Simplicity is prerequisite for reliability.
Programming is one of the most difficult branches of applied mathematics; the poorer mathematicians had better remain pure mathematicians.
The competent programmer is fully aware of the limited size of his own skull. He therefore approaches his task with full humility, and avoids clever tricks like the plague.
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.
There should be no such thing as boring mathematics.
Program testing can be used to show the presence of bugs, but never to show their absence!
Object-oriented programming is an exceptionally bad idea which could only have originated in California.
The lurking suspicion that something could be simplified is the world's richest source of rewarding challenges.
The use of COBOL cripples the mind; its teaching should, therefore, be regarded as a criminal offense.
Perfecting oneself is as much unlearning as it is learning.
Aim for brevity while avoiding jargon.
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.
The students that, like the wild animal being prepared for its tricks in the circus called 'life', expects only training as sketched above, will be severely disappointed: by his standards he will learn next to nothing.
The ability of discerning high quality unavoidably implies the ability of identifying shortcomings.
I mentioned the non-competitive spirit explicitly, because these days, excellence is a fashionable concept. But excellence is a competitive notion, and that is not what we are heading for: we are heading for perfection.
Many mathematicians derive part of their self-esteem by feeling themselves the proud heirs of a long tradition of rational thinking; I am afraid they idealize their cultural ancestors.
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.
Mathematicians are like managers - they want improvement without change.
Teaching to unsuspecting youngsters the effective use of formal methods is one of the joys of life because it is so extremely rewarding.
The effort of using machines to mimic the human mind has always struck me as rather silly. I would rather use them to mimic something better.Collection: Silly
If debugging is the process of removing software bugs, then programming must be the process of putting them in.Collection: Funny
The art of programming is the art of organizing complexity.Collection: Art
Simplicity and elegance are unpopular because they require hard work and discipline to achieve and education to be appreciated.Collection: Hard Work
The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.Collection: Simplicity
Simplicity is a great virtue but it requires hard work to achieve it and education to appreciate it. And to make matters worse: complexity sells better.Collection: Hard Work
The question of whether computers can think is like the question of whether submarines can swim.Collection: Technology
Raise your quality standards as high as you can live with, avoid wasting your time on routine problems, and always try to work as closely as possible at the boundary of your abilities. Do this, because it is the only way of discovering how that boundary should be moved forward.Collection: Trying
Programming in Basic causes brain damage.Collection: Brain
The competent programmer is fully aware of the strictly limited size of his own skull; therefore he approaches the programming task in full humility, and among other things he avoids clever tricks like the plague.Collection: Clever
Much of the excitement we get out of our work is that we don't really know what we are doing.Collection: Excitement
If in physics there's something you don't understand, you can always hide behind the uncharted depths of nature. You can always blame God. You didn't make it so complex yourself. But if your program doesn't work, there is no one to hide behind. You cannot hide behind an obstinate nature. If it doesn't work, you've messed up.Collection: Depth
Computer science is no more about computers than astronomy is about telescopes, biology is about microscopes or chemistry is about beakers and test tubes. Science is not about tools. It is about how we use them, and what we find out when we do.Collection: Tools
If you want more effective programmers, you will discover that they should not waste their time debugging, they should not introduce the bugs to start with.Collection: Debugging
Teaching COBOL ought to be regarded as a criminal act.Collection: Teaching
… what society overwhelmingly asks for is snake oil. Of course, the snake oil has the most impressive names — otherwise you would be selling nothing — like “Structured Analysis and Design”, “Software Engineering”, “Maturity Models”, “Management Information Systems”, “Integrated Project Support Environments” “Object Orientation” and “Business Process Re-engineering”.Collection: Maturity
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" (whatever that may be).Collection: Technology
Some consider the puzzles that are created by their omissions as spicy challenges, without which their texts would be boring; others shun clarity lest their work is considered trivial.Collection: Omission
Several people have told me that my inability to suffer fools gladly is one of my main weaknesses.Collection: People
A convincing demonstration of correctness being impossible as long as the mechanism is regarded as a black box, our only hope lies in not regarding the mechanism as a black box.Collection: Lying
[Though computer science is a fairly new discipline, it is predominantly based on the Cartesian world view. As Edsgar W. Dijkstra has pointed out] A scientific discipline emerges with the - usually rather slow! - discovery of which aspects can be meaningfully 'studied' in isolation for the sake of their own consistency.Collection: Discovery
I now have had my foggy crystal ball for quite a long time. Its predictions are invariably gloomy and usually correct, but I am quite used to that and they won't keep me from giving you a few suggestions, even if it is merely an exercise in futility whose only effect is to make you feel guilty.Collection: Exercise
Write a paper promising salvation, make it a "structured" something or a "virtual" something, or "abstract," "distributed" or "higher-order" or "applicative" and you can almost be certain of having started a new cult.Collection: Writing
I would therefore like to posit that computing's central challenge, how not to make a mess of it, has not yet been met.Collection: Challenges