14 ms·

How do we tell truths that might hurt? (E. Dijkstra, 1975)

66 points by Luyt 14y ago

johncoogan 14y ago
As someone who was born more than a decade after this was written, I can't say I understand the context in which this was written. Would anyone care to elaborate for me? Specifically, I'd like to know what opinions about Fortran, Basic, Cobol, PL/I and APL were common at the time. Also, how was this received?
- fastball 14y ago
  I'd like to know why the author thinks that programming is one of the most difficult branches of mathematics, because I disagree. Is it because they didn't have relatively easy-to-use languages such as Python back then?
  - skrebbel 14y ago
    No, it's because a larger amount of programming was more complicated back then. Resources were significantly more constrained, and converting database result sets to pretty HTML layouts wasn't part of the field yet.
    - Locke1689 14y ago
      No, it's not. Dijkstra believed in programming as a formal discipline. One of his more contentious claims is that most computing scientists who wrote programs (note the "computing", not computer[1]) should use formal methods in addition to programming. In many cases this would mean proving your programs correct. In this sense you are not simply a "code monkey," you are a mathematician generating proofs of algorithmic analysis. Now, of course, he was correct that this is quite difficult, especially if you want to do it for everything. It turns out that the demand for programs which sometimes work is higher than the demand for programs which always work, so most programmers are not mathematicians. However, many of Dijkstra's feelings are being revisited, with a modern twist. The C security disasters of the latter part of the previous century convinced a lot of people that we have become far to lax in our discipline. However, we still recognize that formal proofs of correctness are far too onerous for ordinary programmers. Instead, we'd like to offer the benefits of formal analysis to programmers without any experience with formal analysis. This is the study of type systems. I could go on, but this is a long topic that I really just need to sit down and write a blog post about to cover in any sufficient detail. [1] Computer science is not the study of computers, it's the study of computing
      - jrajav 14y ago
        > I could go on, but this is a long topic that I really just need to sit down and write a blog post about to cover in any sufficient detail. Please do.
  - tikhonj 14y ago
    Some math people I talked to found formal logic to be the hardest branch. Proofs about proofs are maddening. Reasing about reasoning and about things you can't reason about is tricky. Programming--at a high level--is just this with different syntax. Actually, that's both a simplification and an exaggeration. However, Dijkstra was very interested in formal verification, and that really is very much like the study of formal logic. More generally, the study of programming languages and semantics (which is probably most of what he meant by programming as a branch of mathematics) is very closely related to formal logic. And while I personally think it's not nearly as scary as people make it out to be--please don't be afraid of type theory and formal verification!--most people do find it somewhat difficult.
    - duopixel 14y ago
      The first time I understood a formal proof was with Dijkstra: http://www.cs.utexas.edu/~EWD/ewd13xx/EWD1311.PDF http://www.cs.utexas.edu/~EWD/ewd13xx/EWD1311.PDF He is an exceptionally sharp thinker who is able to communicate his thought process with clarity. Even if you don't follow the math you understand how certain proofs can be abstracted from proofs made earlier. I think you are correct, Dijkstra was exceptionally interested in formal verification to the point where he wasn't willing to envision a computing world that was not formally verified. When he said that programming is more difficult to mathematics he was probably envisioning the problems of formal logic with increasingly sophisticated programming structures.
  - pretoriusB 14y ago
    >Is it because they didn't have relatively easy-to-use languages such as Python back then? No, it's because (people like Djikstra at least) didn't regard the stuff we do with Python nowadays as real programming, in the same way you don't regard office doodles as Van Gong style art.
  - RyanZAG 14y ago
    There were (and are) plenty of ways to make some simple scripts that you could term 'programming'. This isn't what Dijkstra is talking about - he's talking about formally correct programming which has gone out of style in favor of unit tests and 'move fast and break things'. Completely different perspective on programming - a scientific approach versus an engineering approach to problem solving. Dijkstra would be very upset by your hacking together Python scripts as programming and he would probably have sent a similar letter to the one in the OP. ;)
- btilly 14y ago
  The easiest way to update it is to replace those with the closest current equivalents. Fortran = C, Basic = PHP, Cobol = Java, PL/I = Perl, and there is nothing on the landscape that is really equivalent to APL. So let me say more about APL. APL basically started as math notation turned into a programming language. In order to type it you needed a special keyboard for all of the extra symbols you needed. It evolved into an incredibly compact and versatile language, with a well-deserved reputation for being hard to read. In fact the classic challenge among APL programmers is that one would write a program in a single line, and the other would try to figure out what it did! The Wikipedia article on the language is at http://en.wikipedia.org/wiki/APL_(programming_language) http://en.wikipedia.org/wiki/APL_(programming_language). They offer the following example of an implementation of Conway's game of life in APL: life←{↑1 ⍵∨.∧3 4=+/,¯1 0 1∘.⊖¯1 0 1∘.⌽⊂⍵} Update: Apparently one or more of my comparisons are offending people. If you'd respond indicating which comparison offends you, I'll explain why I made the comparison.
  - eropple 14y ago
    The comparisons you've made are flippant ones without much serious weight to them. I didn't downvote you, but, for example, COBOL bears no resemblance to Java beyond "it's used for business applications." Unlike COBOL, Java has a thriving non-business ecosystem and is a suitable tool for a lot of varied tasks. And, perhaps more importantly, it is regarded as such--the opinions held of COBOL at the time do not look remotely similar to the opinions about Java today. I can't speak to PL/I : Perl so I won't try, but FORTRAN : C is likewise unfair. BASIC : PHP is closer, but still denies the credit (yes, there's some) that the PHP language, core library, and community deserve. (EDIT: I will totally agree with you that APL is cool, though. ;-) )
    - btilly 14y ago
      I said closest equivalents, not close. And, in terms of understanding a 1975 comment with 2012 language comparisons, I challenge you to do better. As for Java, it, like COBOL, was intentionally designed from the start to subtly restrict programmers so that large groups could work together on extremely portable programs. Both became popular in lots of "boring business applications" that will live forever. And if you think that current opinions about Java are dissimilar from old opinions about COBOL, you need to get out of your echo chamber and learn what adherents of various scripting languages think about Java. If you're tempted to retort that there are more Java programmers than scripting programmers, and Java programmers like the language, a 1975 COBOL programmer could justifiably have said the same thing. The Perl vs PL/I comparison is not original to me. A bit over a decade ago MJD took a 1967 description of PL/I, did word substitution, and came up with http://perl.plover.com/perl67.html http://perl.plover.com/perl67.html. The description fits - both languages combined several previous ones in an idiosyncratic way, with a strong emphasis on making it easy to get stuff done. The result in both cases was a language which made it easy for "sysadmin types" to solve real problems, with solutions that in time could become problems of their own. The FORTRAN to C comparison is, admittedly, unfair as languages. But both have the characteristic of being low-level languages that are not (by current standards) very expressive, with large established code bases, riddled with repetitive mistakes that cause problems. You admit that BASIC to PHP is better. If you think that I have failed to give the PHP language, core library, and community the full iota of respect that they deserve, then I likewise believe that you fail to give Kemeny and Kurtz full respect for deciding in the early 60s that computing was going to be a universal right, and there needed to be a programming language, for non-programmers, that would let them unleash that potential. And then designing a language that successfully served that purpose for decades.
- deleted 14y ago
  [deleted]
aeflash 14y ago
I wonder what the uncomfortable truths that everyone is ignoring are in today's programming world?
- jrockway 14y ago
  PHP.
  - randallsquared 14y ago
    Is there some uncomfortable truth about PHP that's not being shouted from the rooftops in every thread about PHP? If so, what is it?
    - chromatic 14y ago
      Perhaps "Nothing else solves the deployment problem as well as PHP did." (No, not even "git push to deploy".)
  - chimeracoder 14y ago
    Nah, that's the one that's popular ("pleasant") to recognize. If I had to hazard a guess, I'd imagine Dijkstra would have a word or two to say about callbacks, given his famously strong beliefs about GOTOs....
- jlouis 14y ago
  HTML .. when PostScript was way better. The many years spent with C and C++ when there are better alternatives around. Microsoft Windows, OSX, Linux when Plan9 exists. OOP. NoSQL and its total misunderstanding of the power of having a declarative query language. Cache coherency, ordering guarantees, where we should opt for less.
  - deleted 14y ago
    [deleted]
  - readme 14y ago
    I think you confused 'truth' with 'things jlouis likes better than others' --- to be fair, djikstra seemed to suffer from the same distortion.
cafard 14y ago
If you are Dijkstra, with a zest that becomes its own attraction. He did a great deal of important work, but seems too often to be remembered for stinging epigrams.
rauljara 14y ago
> How do we tell truths that might hurt? Well, if you are attempting to influence someone like me, not like this. I think Dijkstra's great reputation and 37 years of experience with programming are basically enough for anyone reading this today to take all of his statements as basically true; but if someone published a similar list dissing all your favorite programming languages... well, we've all witnessed internet flame wars. The basic problem here is that the list is nothing but assertions. Dijkstra is 'right' about almost all of them, but there's no proof, or attempt to argue the point here. If you didn't already agree with him, or god forbid, actually use one of the languages, what you'd hear is Dijkstra basically saying you are stupid for using that language. And humans have a very natural tendency when someone calls them stupid to assert angrily that they are not. And then the argument basically becomes a form of "no I'm not stupid for liking Apple products, you're stupid for liking Android." Which is entirely not the point of what Dijkstra is doing. In my experience, the best way to get someone to change their mind is to show them a better way, and show them how and why it is better without ever insulting the old way or implying people who follow it are stupid. Easier said than done, of course. But the insults are unnecessary and, more importantly, distracting. They tend to be more about the ego of the person hurling them than anything else. And stuff is already hard enough to figure out even without egos getting involved.
- tikhonj 14y ago
  That's entirely fair. The most disheartening thing is that what you described is a good way to convince somebody, and even that often doesn't work. (As, I'm sure, many advocates of functional programming know well.) If your goal is to convince somebody of something, this rational approach may be the best, in some sense, but it probably isn't the most efficient. Instead, I imagine a combination of some good points with a bunch of tactics borrowed from advertisers and behavioral psychologists is the most likely to actually convince people. I would love to believe that programmers are all rational and listen only to reason, but I've found this too often to not be the case.
  - pretoriusB 14y ago
    Well, if you could absolutely convince anybody of anything, that would akin to hypnotism and will amount to fascism. So, let's assume that you only want to convince people of things that are indeed true. Then the thing goes awry: how do you know what's true? Maybe it's not, and they are rightfully not convinced. Maybe there are more than one ways that the thing can be seen. Etc. Take something that is "obvious" for some people, like "PHP is a bad language". It's not at all obvious to me that even that one universally true. One could answer, e.g: all languages have sore points so it's no big deal, if reversal of needle-and-haystack is your biggest worry about a library then it's pretty much fine, I can easily find programmers and that's what matters to me, it has never failed my projects, it works for Facebook, it has tools and communities I cannot find elsewhere like Wordpress, etc etc. And PHP is as close-cut a case as it can get. Fighting Fortran? Not so much.
leoh 14y ago
What sort of languages did Dijkstra really like?
- enduser 14y ago
  He didn't use computers much, other than for email and browsing the web. Most of his writing was composed by hand using a fountain pen. He did work on ALGOL 60 and it is believed that he approved of the language. Source: Wikipedia
- sb 14y ago
  In college I was reading a lot of the EWDs (particularly his trip reports, some hilarious stuff there) and IIRC he didn't like C/C++ a lot and thought that functional programming has some promising ideas. This was in the later EWDs, I'd say 1150+. There are some fun quotations of him about APL and Basic.
millstone 14y ago
> Programming is one of the most difficult branches of applied mathematics; the poorer mathematicians had better remain pure mathematicians. This is completely backwards. The majority of papers about programming are accessible to most good programmers, perhaps after a little study. The majority of pure mathematics papers are inaccessible to almost all mathematicians. What programming achievement is comparable in difficulty, complexity, or scope to the Classification of Finite Simple Groups or the Poincaré conjecture?
- dinkumthinkum 14y ago
  There are plenty of mathematicians that don't program very well. Keep in mind, there are many "programmers" that are not really the sort of programmers Dijkstra is talking about. He's not talking about whipping together WP sites with a little JQuery to make dynamic menus.
  - eriksank 14y ago
    What looks the most like traditional mathematics in computing is the η-conversion in the lambda calculus. The η-conversion is any operation on expressions that yields an equivalent expression, on the condition that it is not just a rename, because that would amount to an α-conversion. It is also called mathematical derivation or what other people incorrectly call mathematical "proof". Without denying the merits of being proficient at showing that expressions are equivalent through η-conversion, we can easily see that quite a few mathematicians only use this method to show that the one meaningless and useless expression is equivalent to another not more meaningful one.
    - dinkumthinkum 14y ago
      I'm not sure what this has to do with anything. I suppose you're trying to refute the notion that computing is related to mathematics because of this one trivial and somewhat strange example you bring up, which I suppose is to mean that you think this is really the only thing in computer science that resembles mathematics. I would just say that that is pretty odd.
deleted 14y ago
[deleted]
borplk 14y ago
Breaking news: our computing technology is not perfect, neither is our world He dismisses and complains about every piece of popular technology back then as if the world is about to collapse because hey! look, these apes invented COBOL and FORTRAN. What did he do? Did our world come to an end because how terrible COBOL was? No, we learned some lessons and we paid the price and now we're doing better, this is how it works. Every piece I read from Dijkstra it seems like he is having a hard time accepting the imperfect aspects of our computing technology. He wants the perfection of formal proofs to be everywhere in every program.
- tluyben2 14y ago
  He exaggerated his points because he did see the big picture which became reality; untrained people writing buggy, horrible software. He knew that would happen and tried to use his position to do something about it. And we are doing better? Computers were doing important things back then, but now they are almost driving our cars, they are flying our planes and giving us radiation therapy. All that, usually, without formal proof and with some kind of 'but we use unit tests so ...' attitude. Outsourced if possible because then it's cheap. Of course, humans make more mistakes than buggy software generally, however his point was that we have ways to almost prevent this by properly training software developers and writing proper software. You cannot prevent everything as he suggested (but, again, he exaggerated to make a point); you can make it better by not calling people who did some online course programmers and by creating open and robust systems. If you are young enough, I would be willing to bet that you will, at some time in your life be seriously hurt or even die from the consequence of not taking this seriously enough. You are probably losing money because of software bugs already; besides rounding errors, you (probably) have no idea how many bugs there are in the software which processes your insurance, taxes etc, all written in that evil Cobol by untrained monkeys. I know this for a fact in the Netherlands as I have seen this up close; probably true everywhere.
  - borplk 14y ago
    Hmm...makes sense. I see your point and indeed I do agree. However, again, why didn't he do something practical about the perfect programming languages that he seems to talk about? Whatever technology you name, it is always possible to dismiss it by talking about another level of perfection, but what is it beyond imagination? We could perform our surgeries in this and that way... We could build our cities and buildings in this superior way...
peter_l_downs 14y ago
Besides a mathematical inclination, an exceptionally good mastery of one's native tongue is the most vital asset of a competent programmer. Surprisingly true.
- sb 14y ago
  I love that one, and it always surprises me when I meet people who can't express themselves properly. There are some of the earlier EWDs, where he meets a lot with German computer scientists (in particular one of the founding fathers of the field there, Friedrich L. Bauer, whom he calls "Uncle Fritz"), and it seems that he had good understanding of German, too. There is also an interesting video of Dijkstra from a Netherland's television station (http://www.cs.utexas.edu/~EWD/video-audio/NoorderlichtVideo.html http://www.cs.utexas.edu/~EWD/video-audio/NoorderlichtVideo....)
pretoriusB 14y ago
For a supposedly hard-core science guy, he was not beyond name-calling and BS accusations based on pure opinion.
- rwallace 14y ago
  Indeed, looking back over that list, I'm surprised by the fact that almost everything on it is - and was at the time - simply wrong.

66 points by Luyt 14y ago

As someone who was born more than a decade after this was written, I can't say I understand the context in which this was written. Would anyone care to elaborate for me? Specifically, I'd like to know what opinions about Fortran, Basic, Cobol, PL/I and APL were common at the time. Also, how was this received?

fastball 14y ago
I'd like to know why the author thinks that programming is one of the most difficult branches of mathematics, because I disagree. Is it because they didn't have relatively easy-to-use languages such as Python back then?
- skrebbel 14y ago
  No, it's because a larger amount of programming was more complicated back then. Resources were significantly more constrained, and converting database result sets to pretty HTML layouts wasn't part of the field yet.
  - Locke1689 14y ago
    No, it's not. Dijkstra believed in programming as a formal discipline. One of his more contentious claims is that most computing scientists who wrote programs (note the "computing", not computer[1]) should use formal methods in addition to programming. In many cases this would mean proving your programs correct. In this sense you are not simply a "code monkey," you are a mathematician generating proofs of algorithmic analysis. Now, of course, he was correct that this is quite difficult, especially if you want to do it for everything. It turns out that the demand for programs which sometimes work is higher than the demand for programs which always work, so most programmers are not mathematicians. However, many of Dijkstra's feelings are being revisited, with a modern twist. The C security disasters of the latter part of the previous century convinced a lot of people that we have become far to lax in our discipline. However, we still recognize that formal proofs of correctness are far too onerous for ordinary programmers. Instead, we'd like to offer the benefits of formal analysis to programmers without any experience with formal analysis. This is the study of type systems. I could go on, but this is a long topic that I really just need to sit down and write a blog post about to cover in any sufficient detail. [1] Computer science is not the study of computers, it's the study of computing
    - jrajav 14y ago
      > I could go on, but this is a long topic that I really just need to sit down and write a blog post about to cover in any sufficient detail. Please do.
- tikhonj 14y ago
  Some math people I talked to found formal logic to be the hardest branch. Proofs about proofs are maddening. Reasing about reasoning and about things you can't reason about is tricky. Programming--at a high level--is just this with different syntax. Actually, that's both a simplification and an exaggeration. However, Dijkstra was very interested in formal verification, and that really is very much like the study of formal logic. More generally, the study of programming languages and semantics (which is probably most of what he meant by programming as a branch of mathematics) is very closely related to formal logic. And while I personally think it's not nearly as scary as people make it out to be--please don't be afraid of type theory and formal verification!--most people do find it somewhat difficult.
  - duopixel 14y ago
    The first time I understood a formal proof was with Dijkstra: http://www.cs.utexas.edu/~EWD/ewd13xx/EWD1311.PDF http://www.cs.utexas.edu/~EWD/ewd13xx/EWD1311.PDF He is an exceptionally sharp thinker who is able to communicate his thought process with clarity. Even if you don't follow the math you understand how certain proofs can be abstracted from proofs made earlier. I think you are correct, Dijkstra was exceptionally interested in formal verification to the point where he wasn't willing to envision a computing world that was not formally verified. When he said that programming is more difficult to mathematics he was probably envisioning the problems of formal logic with increasingly sophisticated programming structures.
- pretoriusB 14y ago
  >Is it because they didn't have relatively easy-to-use languages such as Python back then? No, it's because (people like Djikstra at least) didn't regard the stuff we do with Python nowadays as real programming, in the same way you don't regard office doodles as Van Gong style art.
- RyanZAG 14y ago
  There were (and are) plenty of ways to make some simple scripts that you could term 'programming'. This isn't what Dijkstra is talking about - he's talking about formally correct programming which has gone out of style in favor of unit tests and 'move fast and break things'. Completely different perspective on programming - a scientific approach versus an engineering approach to problem solving. Dijkstra would be very upset by your hacking together Python scripts as programming and he would probably have sent a similar letter to the one in the OP. ;)
btilly 14y ago
The easiest way to update it is to replace those with the closest current equivalents. Fortran = C, Basic = PHP, Cobol = Java, PL/I = Perl, and there is nothing on the landscape that is really equivalent to APL. So let me say more about APL. APL basically started as math notation turned into a programming language. In order to type it you needed a special keyboard for all of the extra symbols you needed. It evolved into an incredibly compact and versatile language, with a well-deserved reputation for being hard to read. In fact the classic challenge among APL programmers is that one would write a program in a single line, and the other would try to figure out what it did! The Wikipedia article on the language is at http://en.wikipedia.org/wiki/APL_(programming_language) http://en.wikipedia.org/wiki/APL_(programming_language). They offer the following example of an implementation of Conway's game of life in APL: life←{↑1 ⍵∨.∧3 4=+/,¯1 0 1∘.⊖¯1 0 1∘.⌽⊂⍵} Update: Apparently one or more of my comparisons are offending people. If you'd respond indicating which comparison offends you, I'll explain why I made the comparison.
- eropple 14y ago
  The comparisons you've made are flippant ones without much serious weight to them. I didn't downvote you, but, for example, COBOL bears no resemblance to Java beyond "it's used for business applications." Unlike COBOL, Java has a thriving non-business ecosystem and is a suitable tool for a lot of varied tasks. And, perhaps more importantly, it is regarded as such--the opinions held of COBOL at the time do not look remotely similar to the opinions about Java today. I can't speak to PL/I : Perl so I won't try, but FORTRAN : C is likewise unfair. BASIC : PHP is closer, but still denies the credit (yes, there's some) that the PHP language, core library, and community deserve. (EDIT: I will totally agree with you that APL is cool, though. ;-) )
  - btilly 14y ago
    I said closest equivalents, not close. And, in terms of understanding a 1975 comment with 2012 language comparisons, I challenge you to do better. As for Java, it, like COBOL, was intentionally designed from the start to subtly restrict programmers so that large groups could work together on extremely portable programs. Both became popular in lots of "boring business applications" that will live forever. And if you think that current opinions about Java are dissimilar from old opinions about COBOL, you need to get out of your echo chamber and learn what adherents of various scripting languages think about Java. If you're tempted to retort that there are more Java programmers than scripting programmers, and Java programmers like the language, a 1975 COBOL programmer could justifiably have said the same thing. The Perl vs PL/I comparison is not original to me. A bit over a decade ago MJD took a 1967 description of PL/I, did word substitution, and came up with http://perl.plover.com/perl67.html http://perl.plover.com/perl67.html. The description fits - both languages combined several previous ones in an idiosyncratic way, with a strong emphasis on making it easy to get stuff done. The result in both cases was a language which made it easy for "sysadmin types" to solve real problems, with solutions that in time could become problems of their own. The FORTRAN to C comparison is, admittedly, unfair as languages. But both have the characteristic of being low-level languages that are not (by current standards) very expressive, with large established code bases, riddled with repetitive mistakes that cause problems. You admit that BASIC to PHP is better. If you think that I have failed to give the PHP language, core library, and community the full iota of respect that they deserve, then I likewise believe that you fail to give Kemeny and Kurtz full respect for deciding in the early 60s that computing was going to be a universal right, and there needed to be a programming language, for non-programmers, that would let them unleash that potential. And then designing a language that successfully served that purpose for decades.
deleted 14y ago
[deleted]

aeflash 14y ago

I wonder what the uncomfortable truths that everyone is ignoring are in today's programming world?

jrockway 14y ago
PHP.
- randallsquared 14y ago
  Is there some uncomfortable truth about PHP that's not being shouted from the rooftops in every thread about PHP? If so, what is it?
  - chromatic 14y ago
    Perhaps "Nothing else solves the deployment problem as well as PHP did." (No, not even "git push to deploy".)
- chimeracoder 14y ago
  Nah, that's the one that's popular ("pleasant") to recognize. If I had to hazard a guess, I'd imagine Dijkstra would have a word or two to say about callbacks, given his famously strong beliefs about GOTOs....
jlouis 14y ago
HTML .. when PostScript was way better. The many years spent with C and C++ when there are better alternatives around. Microsoft Windows, OSX, Linux when Plan9 exists. OOP. NoSQL and its total misunderstanding of the power of having a declarative query language. Cache coherency, ordering guarantees, where we should opt for less.
- deleted 14y ago
  [deleted]
- readme 14y ago
  I think you confused 'truth' with 'things jlouis likes better than others' --- to be fair, djikstra seemed to suffer from the same distortion.

cafard 14y ago

If you are Dijkstra, with a zest that becomes its own attraction. He did a great deal of important work, but seems too often to be remembered for stinging epigrams.

rauljara 14y ago

> How do we tell truths that might hurt? Well, if you are attempting to influence someone like me, not like this. I think Dijkstra's great reputation and 37 years of experience with programming are basically enough for anyone reading this today to take all of his statements as basically true; but if someone published a similar list dissing all your favorite programming languages... well, we've all witnessed internet flame wars. The basic problem here is that the list is nothing but assertions. Dijkstra is 'right' about almost all of them, but there's no proof, or attempt to argue the point here. If you didn't already agree with him, or god forbid, actually use one of the languages, what you'd hear is Dijkstra basically saying you are stupid for using that language. And humans have a very natural tendency when someone calls them stupid to assert angrily that they are not. And then the argument basically becomes a form of "no I'm not stupid for liking Apple products, you're stupid for liking Android." Which is entirely not the point of what Dijkstra is doing. In my experience, the best way to get someone to change their mind is to show them a better way, and show them how and why it is better without ever insulting the old way or implying people who follow it are stupid. Easier said than done, of course. But the insults are unnecessary and, more importantly, distracting. They tend to be more about the ego of the person hurling them than anything else. And stuff is already hard enough to figure out even without egos getting involved.

tikhonj 14y ago
That's entirely fair. The most disheartening thing is that what you described is a good way to convince somebody, and even that often doesn't work. (As, I'm sure, many advocates of functional programming know well.) If your goal is to convince somebody of something, this rational approach may be the best, in some sense, but it probably isn't the most efficient. Instead, I imagine a combination of some good points with a bunch of tactics borrowed from advertisers and behavioral psychologists is the most likely to actually convince people. I would love to believe that programmers are all rational and listen only to reason, but I've found this too often to not be the case.
- pretoriusB 14y ago
  Well, if you could absolutely convince anybody of anything, that would akin to hypnotism and will amount to fascism. So, let's assume that you only want to convince people of things that are indeed true. Then the thing goes awry: how do you know what's true? Maybe it's not, and they are rightfully not convinced. Maybe there are more than one ways that the thing can be seen. Etc. Take something that is "obvious" for some people, like "PHP is a bad language". It's not at all obvious to me that even that one universally true. One could answer, e.g: all languages have sore points so it's no big deal, if reversal of needle-and-haystack is your biggest worry about a library then it's pretty much fine, I can easily find programmers and that's what matters to me, it has never failed my projects, it works for Facebook, it has tools and communities I cannot find elsewhere like Wordpress, etc etc. And PHP is as close-cut a case as it can get. Fighting Fortran? Not so much.

leoh 14y ago

What sort of languages did Dijkstra really like?

enduser 14y ago
He didn't use computers much, other than for email and browsing the web. Most of his writing was composed by hand using a fountain pen. He did work on ALGOL 60 and it is believed that he approved of the language. Source: Wikipedia
sb 14y ago
In college I was reading a lot of the EWDs (particularly his trip reports, some hilarious stuff there) and IIRC he didn't like C/C++ a lot and thought that functional programming has some promising ideas. This was in the later EWDs, I'd say 1150+. There are some fun quotations of him about APL and Basic.

millstone 14y ago

> Programming is one of the most difficult branches of applied mathematics; the poorer mathematicians had better remain pure mathematicians. This is completely backwards. The majority of papers about programming are accessible to most good programmers, perhaps after a little study. The majority of pure mathematics papers are inaccessible to almost all mathematicians. What programming achievement is comparable in difficulty, complexity, or scope to the Classification of Finite Simple Groups or the Poincaré conjecture?

dinkumthinkum 14y ago
There are plenty of mathematicians that don't program very well. Keep in mind, there are many "programmers" that are not really the sort of programmers Dijkstra is talking about. He's not talking about whipping together WP sites with a little JQuery to make dynamic menus.
- eriksank 14y ago
  What looks the most like traditional mathematics in computing is the η-conversion in the lambda calculus. The η-conversion is any operation on expressions that yields an equivalent expression, on the condition that it is not just a rename, because that would amount to an α-conversion. It is also called mathematical derivation or what other people incorrectly call mathematical "proof". Without denying the merits of being proficient at showing that expressions are equivalent through η-conversion, we can easily see that quite a few mathematicians only use this method to show that the one meaningless and useless expression is equivalent to another not more meaningful one.
  - dinkumthinkum 14y ago
    I'm not sure what this has to do with anything. I suppose you're trying to refute the notion that computing is related to mathematics because of this one trivial and somewhat strange example you bring up, which I suppose is to mean that you think this is really the only thing in computer science that resembles mathematics. I would just say that that is pretty odd.

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borplk 14y ago

Breaking news: our computing technology is not perfect, neither is our world He dismisses and complains about every piece of popular technology back then as if the world is about to collapse because hey! look, these apes invented COBOL and FORTRAN. What did he do? Did our world come to an end because how terrible COBOL was? No, we learned some lessons and we paid the price and now we're doing better, this is how it works. Every piece I read from Dijkstra it seems like he is having a hard time accepting the imperfect aspects of our computing technology. He wants the perfection of formal proofs to be everywhere in every program.

tluyben2 14y ago
He exaggerated his points because he did see the big picture which became reality; untrained people writing buggy, horrible software. He knew that would happen and tried to use his position to do something about it. And we are doing better? Computers were doing important things back then, but now they are almost driving our cars, they are flying our planes and giving us radiation therapy. All that, usually, without formal proof and with some kind of 'but we use unit tests so ...' attitude. Outsourced if possible because then it's cheap. Of course, humans make more mistakes than buggy software generally, however his point was that we have ways to almost prevent this by properly training software developers and writing proper software. You cannot prevent everything as he suggested (but, again, he exaggerated to make a point); you can make it better by not calling people who did some online course programmers and by creating open and robust systems. If you are young enough, I would be willing to bet that you will, at some time in your life be seriously hurt or even die from the consequence of not taking this seriously enough. You are probably losing money because of software bugs already; besides rounding errors, you (probably) have no idea how many bugs there are in the software which processes your insurance, taxes etc, all written in that evil Cobol by untrained monkeys. I know this for a fact in the Netherlands as I have seen this up close; probably true everywhere.
- borplk 14y ago
  Hmm...makes sense. I see your point and indeed I do agree. However, again, why didn't he do something practical about the perfect programming languages that he seems to talk about? Whatever technology you name, it is always possible to dismiss it by talking about another level of perfection, but what is it beyond imagination? We could perform our surgeries in this and that way... We could build our cities and buildings in this superior way...

peter_l_downs 14y ago

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

sb 14y ago
I love that one, and it always surprises me when I meet people who can't express themselves properly. There are some of the earlier EWDs, where he meets a lot with German computer scientists (in particular one of the founding fathers of the field there, Friedrich L. Bauer, whom he calls "Uncle Fritz"), and it seems that he had good understanding of German, too. There is also an interesting video of Dijkstra from a Netherland's television station (http://www.cs.utexas.edu/~EWD/video-audio/NoorderlichtVideo.html http://www.cs.utexas.edu/~EWD/video-audio/NoorderlichtVideo....)

pretoriusB 14y ago

For a supposedly hard-core science guy, he was not beyond name-calling and BS accusations based on pure opinion.

rwallace 14y ago
Indeed, looking back over that list, I'm surprised by the fact that almost everything on it is - and was at the time - simply wrong.