Talk:Edsger W. Dijkstra

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Latest comment: 9 years ago by Myron Aub in topic New info about "telescope" quote
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GOTO statement considered harmful[edit]

"GOTO statement considered harmful" is listed as a "verified" quote, but the Wikipedia article on Dijkstra says: "The paper's famous title was not the work of Dijkstra, but of Niklaus Wirth, then editor of Communications of the ACM." So according to that article, the quote is not attributed to Dijkstra at all. I don't know which is correct, can somebody look into this please? -- user "Haakon" at wikipedia.

It's not a quote, but an article title. Article by EWD, title change by Niklaus Wirth. Just follow the links under "Wrongly attributed".

Simplicity is prerequisite for reliability[edit]

Found this quote: "The price of reliability is the pursuit of the utmost simplicity." by C.A.R. Hoare, in "The Emperor's Old Clothes" (1980 ACM Turing Award Lecture). Maybe E.W.Dijkstra said something to the same effect, if anyone knows for sure, please identify article/location? Then this: some quotes are under "Attributed", but with EWDxxx source mentioned. May I suggest: if you know the exact source, then check that source, quote EXACT, and move it to "Verified"? Leave it under "Attributed" only when you don't know where it came from. Alwin Henseler

This page refers to EWD498 as the source of this quote, but it doesn't appear anywhere in that document. If you look at the PDF version, it's just not there. Also, a search through Google Books shows the quote missing, as well. Vocaro 01:23, 6 April 2008 (UTC)Reply
After further research, I believe this quote should be attributed to Hoare, not Dijkstra. Hamilton Richards of the Dijkstra Arhive dug up the following information:
If you use the EWD Archive's "advanced search" feature to look for "simplicity reliability" with Proximity set to "sentence", you find six matches: 1304, 619, 1175, 1041, 448, and 1284 (498 also shows up, because the search index hasn't been updated since I corrected 498).
In 1304, "The price of reliability is the pursuit of the utmost simplicity." is attributed to Tony Hoare.
In 619, the terms appear in "the 1975 Los Angeles Conference on Software Reliability, where C.A.R.Hoare stated emphatically, that for reliability simplicity is an absolute prerequisite."
In 1175, Dijkstra writes "computing science has very convincingly shown that simplicity is a necessary precondition for reliability".
In 1041, "the computing science community has agreed that simplicity is an essential ingredient of reliability."
In 448, Dijkstra quotes Hoare again, "reliability can only be achieved by the utmost simplicity".
In 1284: 'for the sake of reliability and intellectual control we have to keep the design simple".
Since so many of these quotes refer to Hoare, I think he is the true source of the quote.
I don't know of a searchable Hoare web site analogous to the Dijkstra archive, but the quote in EWD 1304 comes from Hoare's Turing Award lecture, "The Emperor's Old Clothes." Originally published in Communications of the ACM, 24(2), 75-83 (February 1981), the article is reprinted as Chapter 1 of C.A.R.Hoare and C.B.Jones, Essays in Computing Science (Prentice Hall, 1989), and the quote appears on page 15.
Vocaro 01:23, 6 April 2008 (UTC)Reply
The transcription of EWD498 available at mentions: "Simplicity is prerequisite for reliability. [Handwritten annotation]". Also mentioned in its source, from -- 11:52, 31 January 2012 (UTC)Reply


I found an amusing quote from Alan Kay on Dijkstra, from his 1997 OOPSLA keynote: 'I don't know how many of you have ever met Dijkstra, but you probably know that arrogance in computer science is measured in nano-Dijkstras.' [audience laughter][1]. -- 20:06, 16 March 2008 (UTC)Reply

I don't know what exactly is so amusing about it. I met Dijkstra and he was a very humble person. (Probably because of this quote: 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. —EdsgerW. Dijkstra, in The Humble Programmer, CACM 1972)

The amusing bit is when Kay talks about what computing science is about in the next minutes. He says that it cannot be tackled by old-fashioned mathematics because the formulas are so much larger than in classical mathematics and new techniques are therefore needed. Sounds like he's been reading his EWDs!


  • Do only what only you can do.
  • Object-oriented programming is an exceptionally bad idea which could only have originated in California.
  • The prisoner falls in love with his chains.
  • Aim for brevity while avoiding jargon.
  • 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.
  • Why has elegance found so little following? Elegance has the disadvantage that hard work is needed to achieve it and a good education to appreciate it.
  • We must not put mistakes into programs because of sloppiness, we have to do it systematically and with care.
  • I realized that my prior projects were just finger warm-ups. Now I have to tackle complexity itself. But it took long, before I had assembled the courage to do so.
    • Something very similar appears in EWD 1166.
  • Abstract data types are a remarkable theory, whose purpose is to describe stacks
  • If debugging is the process of removing software bugs, then programming must be the process of putting them in.


I've moved it to the misattributed section, having found its true source. See and notice 'telescope' shows up nowhere in the EWDs ( --Gwern 15:54, 29 August 2011 (UTC)Reply

I found an even earlier source in the beginning of Lecture one of Hal Abelson's famous lectures on the Structure and Interpretation of Computer Programs (SICP): available on an MIT site or on youtube. Just look at the first few minutes.

New info about "telescope" quote[edit]

I signal the following my investigations about the "telescope" quote:


where it seems that, according Jacques Arsac, this quote was first stated by Alan Perlis in 1968 but he didn't publish it and Arsac wrote it at least since 1987.

--Myron Aub (talk) 21:04, 16 September 2014 (UTC)Reply