Summary:

1. A purported (but erroneous) proof of S was published in the mathematical literature, so that
2. S was generally accepted as true for a significant period of time, say at least two years, but
3. S is actually false

There are many examples of statements that were believed without proof that turned out to be false, such as any number of decidability and completeness (non-)theorems. If it turns out that P=NP, this will be one of those type, but as yet there is no generally accepted proof to the contrary, so it is not an example. Similarly, if would be quite surprising to learn that the Goldbach conjecture was false, but at present mathematicians do not generally believe that it has been proved to be true, so the Goldbach conjecture is not an example of this type, and is unlikely ever to be.

There are a lot of results that could have gone one way or another, such as the three-dimensional kissing number problem. In this case some people believing they could go one way and some the other, and then they found that it was one way, but no proof to the contrary was ever widely accepted.

Then we have results like the independence of the parallel postulate, where people thought for a long time that it should be implied by the rest of Euclidean geometry, and tried to prove it, but couldn't, and eventually it was determined to be independent. But again, there was no generally accepted proof that it was implied by the other postulates. So mathematics got the right answer in this case: the mathematicians tried to prove a false statement, and failed, and then eventually figured it out.

Alfred Kempe is famous for producing an erroneous proof of the four-color map theorem, which was accepted for eleven years before the error was detected. But the four-color map theorem is true. I want an example of a false statement that was believed for years because of an erroneous proof.

If there isn't one, that is an astonishing declaration of success for all of mathematics and for its deductive methods. 2300 years without one major screwup!

It seems too good to be true. Is it?

Glossary for non-mathematicians

• The "decidability and completeness" results I allude to include the fact that the only systems of mathematical axioms strong enough to prove all true statements of arithmetic, are those that are so strong that they also prove all the false statements of arithmetic. A number of results of this type were big surprises in the early part of the 20th century.

• If "P=NP" were true, then it would be possible to efficiently find solutions to any problem whose solutions could be efficiently checked for correctness. For example, it...

We have assigned a product manager to discuss IBM WebSphere Portal integration with your technical lead. And the VP of Marketing needs to talk to you. We have made a commitment to all-singing, all-dancing web services and he needs a forty-minute presentation explaining how your project will be implemented with web services throughout. You look pale. Is there a problem?

    80818

   1304 toString            
   1219 run                 
    663 equals              
    496 hashCode            
    440 actionPerformed     
    439 getName             
    383 contains            
    352 accept              
    320 remove              
    285 reset               
    280 get                 
    278 getCharacterEncoding
    277 paint               
    261 read                
    258 add                 
    256 write               
    224 main                
    216 close               
    213 clone               
    204 getValue            
    199 getType             
    193 next                
    191 createUI            
    189 size                
    175 clear               
    168 getPreferredSize    
    167 print               
    159 init                
    152 newEncoder          
    152 newDecoder          
    150 propertyChange      
    145 update              
    140 historicalName      
    134 getMinimumSize      
    130 debug               
    120 translate           
    119 setValue            
    116 set                 
    116 put                 
    110 getEncoderIndex2    
    110 append              
    107 isEmpty             
    107 getInstance         
    104 initialize          
    103 getMaximumSize      
    102 getBorderInsets     
    102 error               
    102 dispose             
    101 writeObject         

  19984 get       
   5449 set       
   3555 is        
   1604 to        
   1534 create    
   1441 visit     
   1180 add       
    776 remove    
    707 write     
    642 update    
    532 mouse     
    501 hash      
    500 check     
    477 new       
    471 has       
    468 print     
    449 action    
    412 read      
    374 install   
    357 parse     
    330 paint     
    302 uninstall 
    294 handle    
    260 put       
    258 init      
    252 process   
    223 next      
    223 find      
    220 end       
    217 load      
    217 build     
    202 can ...
  

What is user space? User space is the location in the filesystem where users put their personal files-- their "stuff". Here's the user space folder structure in the Windows XP operating system:

\Documents and Settings\User\
   \Application Data
   \Cookies
   \Desktop
   \Favorites
   \Local Settings
   \My Documents
      \My Music
      \My Pictures
   \My Recent Documents
   \NetHood
   \PrintHood
   \SendTo
   \Start Menu

And here's the user space folder structure in the Windows Vista operating system:

\Users\User\
   \AppData
      \Local
      \Roaming
   \Contacts
   \Desktop
   \Documents
   \Downloads
   \Favorites
   \Links
   \Music
   \Pictures
   \Saved Games
   \Searches
   \Videos

This new Vista user space folder structure may seem oddly familiar to people using operating systems based on Unix. It gives new life to the famous quote "Those who do not understand Unix are condemned to reinvent it, poorly". Regardless, I'm glad we no longer have to deal with a scarily long default user path -- with aggravating embedded spaces, even-- to our personal stuff. If a user is keeping notes in a text file, we can reasonably expect to find those notes at the following path:

\Documents and Settings\User\My Documents\notes.txt
\Users\User\Documents\notes.txt

Now that we've established what and where user space is, I have a message for all the programmers reading this-- including myself. Keep your dirty, filthy paws out of my personal user space!

Take a look in your Documents folder right now. Go ahead. Look. Do you see any files or folders in there that you personally did not create? If so, you've been victimized. Applications should never create or modify anything in your documents folder without your permission. And yet, sadly, it happens all the time. Applications, and more specifically, the programmers who wrote those applications, think it's perfectly A-OK to carpet bomb your personal user space with their junk.

Well, it isn't.

As Omar Shahine originally pointed out almost two years ago, we should be mad as hell, and we shouldn't take it any more. If applications need to store shared files, that's what the \AppData and \Application Data folders are for. In OS X, which inherits a lot of filesystem conventions from BSD Unix, Apple has a great set of guidance appropriately titled Don't Pollute User...

Optimising your notation to not confuse people in the first 10 minutes of seeing it but to hinder readability ever after is a really bad mistake.

The impression that the phrase “this interface feature is intuitive” leaves is that the interface works the way the user does, that normal human “intuition” suffices to use it, that neither training nor rational thought is necessary, and that it will feel “natural.” We are said to “intuit” a concept when we seem to suddenly understand it without any apparent effort or previous exposure to the idea.

It is clear that a user interface feature is “intuitive” insofar as it resembles or is identical to something the user has already learned. In short, “intuitive” in this context is an almost exact synonym of “familiar.”

The term “intuitive” is associated with approval when applied to an interface, but this association and the magazines’ rating systems raise the issue of the tension between improvement and familiarity. As an interface designer I am often asked to design a “better” interface to some product. Usually one can be designed such that, in terms of learning time, eventual speed of operation (productivity), decreased error rates, and ease of implementation it is superior to competing or the client’s own products. Even where my proposals are seen as significant improvements, they are often rejected nonetheless on the grounds that they are not intuitive.

It is a classic “catch 22.” The client wants something that is significantly superior to the competition. But if superior, it cannot be the same, so it must be different (typically the greater the improvement, the greater the difference). Therefore it cannot be intuitive, that is, familiar. What the client usually wants is an interface with at most marginal differences that, somehow, makes a major improvement. This can be achieved only on the rare occasions where the original interface has some major flaw that is remedied by a minor fix.

A programming language that doesn’t change the way you think about programming is not worth knowing.

    foreach $k (keys %in) {
            if ($k eq q1) {
                    if ($in{$k} eq agree) {
                            $count{q10} = $count{q10} + 1;
                    }
                    if ($in{$k} eq disaagree) {
                            $count{q11} = $count{q11} + 1;
                    }
            }
            if ($k eq q2) {
                    @q2split = split(/\0/, $in{$k});
                    foreach (@q2split) {
                            $count{$_} = $count{$_} + 1;
                    }
            }
            if ($k eq q3) {
                    $count{$in{$k}} = $count{$in{$k}} + 1;
            }

            ...
     }   

    if ($in{q1} eq agree) {
            $count{q10} = $count{q10} + 1;
    }
    if ($in{q1} eq disaagree) {
            $count{q11} = $count{q11} + 1;
    }

    @q2split = split(/\0/, $in{q2});
    foreach (@q2split) {
            $count{$_} = $count{$_} + 1;
    }

    $count{$in{q3}} = $count{$in{q3}} + 1;
    ...

This is the sort of mistake you expect from an intern. I chuckled and corrected him. But I've seen it several times since from non-interns.

Here's another example. I am not making this up. Whether it's more or less odious than the intern code is up to you to decide:

         foreach $location_name (%LOCATION ) {
                $location_code = $LOCATION{$location_name};

                if ($location_name eq $location ) {

                    printf FILE "$location_code\,";
                        printf FILE "%4s", "$min3\,";
                        printf FILE "%4s", "$max3\,";
                        printf FILE "%1s", "$wx3\n";

                }      

        } 

        printf FILE "$LOCATION{$location}\,";
            printf FILE "%4s", "$min3\,";
            printf FILE "%4s", "$max3\,";
            printf FILE "%1s", "$wx3\n";

        for my $k (keys %hash) {
          if ($k eq "name") {
            $hash{$k}++;
          }
        }

(x-posted to The Kugelmass Episodes)

Bill Benzon calls our attention to a new blog entry by Stanley Fish, posted by The New York Times here.

It is easy to imagine how, after a lifetime of dedicated scholarship, an emeritus professor like Fish might react in frustration against the platitudes in Education’s End, a new book by professor of law Anthony Kronman. Kronman has little to offer us; his vision of college as a place for the “nurturing of those intellectual and moral habits that together form the basis for living the best life one can” is a rhetorically tepid, repackaged version of a pedagogical philosophy shared by many earlier authors, including Matthew Arnold and Michel de Montaigne. Montaigne figures prominently in Alexander Nehamas’s book The Art of Living, which is entirely devoted to the enormous history of this idea within the Western philosophical tradition alone, to say nothing of history, literary studies, or the other constituent disciplines of the humanities.

That said, the banality of Kronman’s prose is no excuse for what Fish has written. Fish ends his post thus:

To the question “of what use are the humanities?”, the only honest answer is none whatsoever. And it is an answer that brings honor to its subject. Justification, after all, confers value on an activity from a perspective outside its performance. An activity that cannot be justified is an activity that refuses to regard itself as instrumental to some larger good. The humanities are their own good. There is nothing more to say, and anything that is said – even when it takes the form of Kronman’s inspiring cadences – diminishes the object of its supposed praise.

The crux of Fish’s argument against literature as an agent of moral self-fashioning goes like this:

If [Kronman’s position] were true, the most generous, patient, good-hearted and honest people on earth would be the members of literature and philosophy departments, who spend every waking hour with great books and great thoughts, and as someone who’s been there (for 45 years) I can tell you it just isn’t so. Teachers and students of literature and philosophy don’t learn how to be good and wise; they learn how to analyze literary effects and to distinguish between different accounts of the foundations of knowledge.

It my sincere belief that this argument is worthless. I hope, when I am finished, that it will be ashamed to show its face again. It is hardly original with Fish; rather, it is everywhere, since it makes scholars in the...

Fish’s current blog entry mounts a defense of the humanities. Here’s his concluding paragraph:

To the question “of what use are the humanities?”, the only honest answer is none whatsoever. And it is an answer that brings honor to its subject. Justification, after all, confers value on an activity from a perspective outside its performance. An activity that cannot be justified is an activity that refuses to regard itself as instrumental to some larger good. The humanities are their own good. There is nothing more to say, and anything that is said – even when it takes the form of Kronman’s inspiring cadences – diminishes the object of its supposed praise.

He’s attracted 181 comments as of 1:35 PM Eastern time; the number seems to rise by the minute. I’ve not read them.

The story so far: Plato has banished the poets from his ideal Republic ("You will know that the only poetry that should be allowed in a perfectly managed state is hymns to the gods and paeans in praise of good men; once you go beyond that and admit the sweet lyric or epic muse, pleasure and pain become your rulers instead of law and the rational principles …").  He does this on the grounds that (a) they peddle copies of copies, moving people further away from the true realm of the Forms, (b) they lie, and (c) they encourage passions, when as any fule kno passions must be manfully (or, I guess, womanfully) repressed: “poetry feeds and waters the passions, weeds that should rather be killed by drought” [606a-d].  Aha, says his pupil, Aristotle.  Not so.  Which is to say, I agree with you that man should not be governed by his emotions; but, rather than encouraging such emotional incontinence, poetry is an effective treatment for it:

Tragedy is, then, a representation of an action that is heroic and complete and of a certain magnitude—by means of language enriched with all kinds of ornament, each used separately in the different parts of the play: it represents men in action and does not use narrative, and through pity and terror it effects a Κάθαρσις of these and similar emotions.  [Aristotle, Poetics, 1449b]

We might put it this way: the debate is whether tragedy is tonic or cathartic.  I’m teaching a course on tragedy this term, amongst other things, and have been reading a fair few books on the subject recently, one of which (Terry Eagleton’s Sweet Violence, I think, although my memory is hazy) likens it to modern-day debates on the pornography or violent video games: one camp taking the Platonic view that such things only roil-up socially dangerous feelings and ought to be banished, the other the Aristotelian view that they provide a healthy vent by which such emotions can be harmlessly released.

Then again, before getting stuck into the preparatory reading for this course, I’d assumed that ‘catharsis’ for Aristotle meant (as some critics think it does) something like ‘bring these emotions, pity and terror, into a healthy balance in the body’.  But looking over Aristotle again, I’m wondering.  For the Greeks, katharsis was a term with strong medical overtones: purging in a theraputic sense ... emetics, laxatics, the whole pre-modern doctoring perscription.  The aim of such an...

Google book search is a good way to answer questions like that, because if "squillion" is widely used, you will find a lot of examples of it. And indeed it is widely used, and I did find a lot of examples of it. So there was no need to remove it form the article.

One of the Google hits was from the Cormac Ó Cuilleanáin translation of Giovanni Boccaccio's Decameron. The Decameron is a great classic of Italian Renaissance literature, probably the greatest classic that Italian has, after Dante's Divine Comedy. It was written around 1350. In this particular chapter (the tenth story on the sixth day, if you want to look it up) Guccio, a priest, is trying to seduce a hideous kitchen-maid:

He sat himself down by the fire—although this was August—and struck up a conversation with the wench in question (Nuta by name), informing her that he was by rights a member of the gentry and had more than a squillion florins in the bank, not counting those he had to give to other people...

The kitchen-maid, by the way, is described as having "a pair of tits like two baskets of manure".

This was amusing, and as I had never read the Decameron, I wanted to read more, and learn how it turned out. But the Google excerpt was limited, so I asked the library to get me a copy of that version of the Decameron. Of course they have many copies on the shelf, but not that particular translation. So I asked the interlibrary loan people for it, and they got it for me.

When it arrived, I was rather dismayed. The ILL people get the book from the most convenient place, and that means that it often comes from the Drexel library, up the street, or the Temple library, across town, or the West Chester Community College library, or Lehigh University, about an hour away in Bethlehem. (Steel Bethlehem, of course, not Jesus Bethlehem.) The farthest I had ever gotten a book from was an extremely obscure quilting manual that Lorrie asked for; it eventually arrived from the Sno-Isles regional library system of

The documentation for a design pattern describes the context in which the pattern is used, the forces within the context that the pattern seeks to resolve, and the suggested solution. [For example:] The visitor design pattern is a way of separating an algorithm from an object structure. A practical result of this separation is the ability to add new operations to existing object structures without modifying those structures.

Fools ignore complexity. Pragmatists suffer it. Some can avoid it. Geniuses remove it.

A programming language is low level when its programs require attention to the irrelevant.

third n | even n = 1
        | odd n  = 0

I've often thought that software developers were akin to Magpies: birds who are notorious for stealing shiny items to decorate their complex nests. Like Magpies, software developers are unusually smart and curious creatures, almost by definition. But we are too easily distracted by shiny new toys and playthings.

I no longer find Scott Hanselman's Ultimate Developer Tool list inspiring. Instead, it's fatiguing. The pace of change in the world of software is relentless. We're so inundated with the Shiny and the New that the very concepts themselves start to disintegrate, the words repeated over and over and over until they devolve into a meaningless stream of vowels and consonants. "Shiny" and "new" become mundane, even commonplace. It's no longer unique for something to be new, no longer interesting when something is shiny. Eventually, you grow weary of the endless procession of shiny new things.

I'm not alone. Jeremy Zawodny also notes the diminishing luster of shiny new things:

Over a year ago I unsubscribed from Steve's blog because he had a habit of writing in breathless fashion about the latest shiny new thing-- often several times a day. I see too many people I know getting caught up in the breathless hype and forgetting to think about whether the latest shiny new thing really matters in the grand scheme of things.

Dave Slusher concurs:

[Robert Scoble] says that he gets too much email and that is ineffective for getting PR releases to him. He suggests that what you should do now is leave him a message on his Facebook wall. Dear god and/or Bob. In the time I've followed Scoble, I must have seen something like this a dozen times from him. Don't email, Twitter me. Don't Twitter, Pwnce. Jaiku me. Leave a wall message, send an SMS, just call me, email me, don't email me, don't call me. Enough already! I'm not even trying to get in contact with him, and I find this constant migration from platform to platform to be a load of shit that just wearies me. I felt the same way when I dropped TechCrunch, well over a year ago. I got so tired of hearing about another slightly different way of doing what we were already doing and why that tiny difference...

Walt found a reference in Montague Shearman's 1887 book on the history of football in England that specifically mentions this. Folks were playing football in the street, and because of this, Pepys took his coach to Sir Philip Warwicke's, rather than walking.

I didn't ask, but I presume Walt found this by doing some straightforward Google search for "pepys footballs" or something of the sort. For some reason, this did not even occur to me. Once Big Dictionary failed me, I was stumped. Perhaps this marks me as a member of the pre-Internet generation. I imagined this morning that this episode would be repeated, with my daughter Iris in place of Walt. "Oh, Daddy! You're so old-fashioned. Just use a Google search."

Anyway, inspired by Walt's example, or by what I imagined Walt's example to be, I did the search myself, and found the Shearman reference, as well as the following discussion in William Carew Hazlitt's Faiths and Folklore of 1905:

Mission, writing about 1690, says: "In winter foot-ball is a useful and charming exercise. It is a leather ball about as big as one's head, fill'd with wind. This is kick'd about from one to t'other in the streets, by him that can get at it, and that is all the art of it."

Thanks very much, Walt.

• Factor's included reference documentation, written mostly by Slava, is sound and basically complete but not very tutorial-like.
• Slava's blog is the best place to learn about new language features as they're developed.
• I wrote a bunch of introductory blog posts.
• Elie Chaftari wrote an introduction to programming Factor, and he wrote about the FFI.
• You can look at many other blogs about Factor through the Planet Factor aggregator. Scattered around here are many more introductions to Factor.
• The Joy papers by Manfred von Thun provide a theoretical basis for concatenative languages.
• You could try reading some source code in the libraries. Simple demos have the tag demo, which you can query in the vocab browser. The core sequence library is a good place to look for clean,...

(define-struct posn (x y) #:transparent)

(define-struct posn (x y) #f)

(x-posted to The Kugelmass Episodes)

Dear readers,

In the spirit of the wonderful MLAde 2007, produced by two very funny UC Irvine grad students and distributed, guerrilla-style, around the conference, I’m pleased to present this parody of academic blogging, entitled “My Story.”

Summary:

Up, and by coach to Sir Ph. Warwicke's, the streete being full of footballs, it being a great frost, and found him and Mr. Coventry walking in St. James's Parke.

My best guess is that it's big chunks of frozen mud that you have to kick out of the way. Do any gentle readers know for sure?

The Diary of Samuel Pepys has a syndication feed you can subscribe to. You get a diary entry every day or so, with all the names and places linked to a glossary. It's fun reading.

[ Addendum 20080105: The answer. ]

Behave like a doctor whose hospital administrator has just told him that hand-washing is too expensive, and he should stop doing it.

I don’t think I have the right to refuse to slap together quick and dirty code when my employer or client insists. However, if I am asked to develop software that is insecure and places private user data at risk, I will make the personal choice of saying no.

---

The 7 Habits of Highly Effective People is one of the most important books I have ever read. Each of the seven habits has helped me find and travel the path that brings meaning to my life. When I feel lost, I return to my well-thumbed copy and it reconnects me to my values. Very highly recommended.

---

One advantage of being a geek is that our habits-- as such habits go-- are not terribly expensive. I've written before about my interest in auto racing. Instead of spending $100,000 on a sports car, I've built a nifty racing simulation rig that delivers many of the same thrills at a tiny fraction of the price. It's one of my few indulgences, and I'd like to share how I built it with you.

Here are the ingredients:

It's worth noting that the Playseat Evolution is designed to mate with the G25 wheels, pedal, and shifter. The mounting holes match up perfectly. That was a pleasant surprise, as I had to do quite a bit of drilling on the older, original Playseat to get things mounted in the first version of this rig. With the Evolution and G25 combo, it's almost plug and play, although you still have to do some drilling to get the shifter add-on mounted properly.

The premium leather-and-metal (well, mostly) G25 kit includes some fairly esoteric features from a major brand vendor like Logitech, notably a clutch pedal and full shifter kit.

I know $229 may seem like a lot, but it's actually a great deal considering what you'd have to pay for an aftermarket shifter or clutch. You don't have to use these advanced realism features, of course. You can always ignore the clutch pedal, and the shifter can be switched between simple up/down mode and a full 6 speed + reverse layout.

The other item of interest...

Last year, nine of us shared our New Year's resolutions. Naturally, we had to do one better for 2008. So ten brave souls offered up what they've resolved to do differently this year. The declarations were diverse, honest, and inspired -- promising to amp up, dial it down, or altogether reframe.

Escape the Flatland

This year, I resolve to finally take advantage of the many tools that are already at my disposal for quick and easy prototyping.

As an experience designer, probably 80% of what I produce is two dimensional in nature: sketches, diagrams, or wireframes. Most of the time, these documents never make it out of the flatland of print or PDFs. In the past, when it has been crucial to convey how the interaction builds and flows, we've implemented prototype development, which, as you can imagine, takes a lot of time and money. And there will always be a place for these bigger, functionally rich prototypes, but there are many discrete interactions and simplified flows that we can and should be bringing to life for our clients every day.

Fortunately, prototype-worthy features have been added to many of the tools already within our arsenal. So basic prototyping has become a lot cheaper and easier. Here's my plan:

• I'll start by practicing Alexa's excellent tutorial on prototyping with Flash, (which you can read in a soon-to-be-released article on Boxes and Arrows).
• Next, I'll spend some time familiarizing myself with the new UI elements and pages features in Fireworks that claim to make prototyping from existing Adobe CS files faster and virtually painless.
• Finally, I'm going to get comfortable with the action and animation capabilities of (gulp) PowerPoint, which, rumor has it, can be used for more than just bullets!

No more excuses. In 2008, I'm busting out!

Embody the Spirit of Practitioner-ness

Pam Daghlian

I haven't made New Year's resolutions in years. I was in my early double-digits when I realized that we beat ourselves up enough over the silly minutiae of life (things like the parachute pants of the 80s). And me failing to get in shape or to stop giving the "stink eye" to people on the subway would only give me more to feel bad about.

However, this year I'm inspired by my colleagues. I've observed them doing their work in ways I've never experienced in my twenty-some years of bringing home a paycheck. They collaborate instead of jockeying for position. They support one another instead of throwing each other under the bus. They bring creative thinking to their projects and play around with methods and ideas instead of sticking to what's safe because it worked last time. They seem fearless about saying, "I don't know or I'm having trouble solving this problem."

A lot of the methods our practitioners use aren't applicable to my...

More of Poetry 35:7, this time Charles Reznikoff, who might be considered the Objectivist par excellence. At least Zukofsky seems to have considered him so, considering that the founding document of Objectivism, the essay “Sincerity and Objectification: With Special Reference to the Work of Charles Reznikoff,” included in the appendix of the special Poetry issue & from which Zukofsky coined the term “Objectivism” when called upon by the editor Harriet Monroe to come up w/a label for the movement, takes Reznikoff as the exemplar.

As with many of the Objectivists, Reznikoff had an interesting life—not interesting as in you could make a movie out of it, but interesting as a writer’s life, more specifically, as an example of someone who maintained the life of a writer despite deriving no income from it and having no audience. As with most of the Objectivists, an audience finally showed up at the very end of his life and seems to be steadily increasing since his death.

The work itself is a supreme example of Modernist concision, but without any of the referential obscurantism of Zukofsky. Which is not to say that it isn’t baffling: though all of the references may be clear, the poems eschew narrative frames that would explain the importance of the presented scenes, and there is to a degree perhaps unmatched by an other practitioner of vers libre a fearless refusal to distinguish itself from prose by any means other than the unjustified right margin. Reznikoff is not the greatest poet of all time, but represents an idiom developed to its highest level, which is a great accomplishment. And given the importance of his themes—history, religion, life in the city—, he is a poet certainly deserving of a wider audience.

I went to visit Iris at school last week, and stayed for lunch. I was seated with Iris and three other little girls. As the food was served, one of the girls, Riley, made some joke about how the food cart contained guinea pigs instead. This sort of joke is very funny to preschoolers.

My sense of humor is very close to a preschooler's, and I would have thought that this was funny if she had said that the food cart contained clocks, or nose hairs, or a speech in defense of the Corn Laws, or the Trans-Siberian Railroad, or fish-shaped solid waste. But she said guinea pigs, and instead of laughing, I mused aloud that I had never eaten a guinea pig.

Riley informed me that "You can't eat guinea pigs! They're animals, not food."

"Sure you can," I said. "Meat is made from animals."

Riley got this big grin on her face, the one that preschoolers get when they know that the adults are teasing them, and said "Nawww!"

"Yes," I said. "Meat comes from animals."

Riley shook her head. She knew I was joking. A general discussion ensued, with Iris taking my side, and another girl, Flora, taking Riley's. In the end, I did not convince them.

"Well," I said, mostly to myself, at the end, "you girls are in for a rude awakening someday."

Now, I know that not everyone is as direct as I am. And I know that not all non-vegetarians are as concerned as I am about the ethics of eating meat. But wow. I would have thought that someone would have explained to these girls where meat came from, just as a point of interest if nothing else. Or maybe they would have made the connection between chicken-the-food and chicken-the-farm-animal. I mean, they are constantly getting all these stories set on farms. Since three-year-olds ask about a billion questions a day. they must ask around a thousand questions a day about the farms, so how is it that the subject never came up?

Iris was accidentally exposed to a movie version of Charlotte's Web on an airplane, and the plot of Charlotte's Web is that Charlotte is trying to save Wilbur from being turned into smoked ham. Left to myself I wouldn't have exposed Iris to Charlotte's Web so soon—it is too long for her, for one thing—but my point here is that the...

OK, Adam Kotsko objected that I should have known that, for Zizek, ‘Cartesian cogito’ “does not name the argument, but one aspect of subjectivity, which Zizek takes to be more originary and important: namely, the sheer abyss of self-relating negativity.” This doesn’t exactly fit with the discussion in Zizek’s paper. When Zizek says things like “the link between the emergency of cogito and the disintegration and loss of substantial communal identities is thus inherent, and this holds even more for Spinoza than for Descartes” and “Spinoza criticized the Cartesian cogito, he criticized it as a positive ontological entity,” it doesn’t make much sense to suppose that both Spinoza and Descartes were commentators on Zizek. But clearly Adam is right that Zizek is sort of mixing up the history with his own philosophy of mind, and so we ought to just get on with that. Adam cites Tarrying With the Negative [amazon - with search inside]. And, picking that one up, dusting it off - well yes, “Part I: Cogito - the Void Called Subject”. I hadn’t remembered.

Most operating systems have some method of displaying CPU utilization. In Windows, this is Task Manager.

CPU usage is generally represented as a simple percentage of CPU time spent on non-idle tasks. But this is a bit of a simplification. In any modern operating system, the CPU is actually spending time in two very distinct modes:

1. Kernel Mode

   In Kernel mode, the executing code has complete and unrestricted access to the underlying hardware. It can execute any CPU instruction and reference any memory address. Kernel mode is generally reserved for the lowest-level, most trusted functions of the operating system. Crashes in kernel mode are catastrophic; they will halt the entire PC.

2. User Mode

   In User mode, the executing code has no ability to directly access hardware or reference memory. Code running in user mode must delegate to system APIs to access hardware or memory. Due to the protection afforded by this sort of isolation, crashes in user mode are always recoverable. Most of the code running on your computer will execute in user mode.

It's possible to enable display of Kernel time in Task Manager, as I have in the above screenshot. The green line is total CPU time; the red line is Kernel time. The gap between the two is User time.

These two modes aren't mere labels; they're enforced by the CPU hardware. If code executing in User mode attempts to do something outside its purview-- like, say, accessing a privileged CPU instruction or modifying memory that it has no access to -- a trappable exception is thrown. Instead of your entire system crashing, only that particular application crashes. That's the value of User mode.

x86 CPU hardware actually provides four protection rings: 0, 1, 2, and 3. Only rings 0 (Kernel) and 3 (User) are typically used.

If we're only using two isolation rings, it's a bit unclear where device drivers should go-- the code that allows us to use our video cards, keyboards, mice, printers, and so forth. Do these drivers run in Kernel mode, for maximum performance, or do they run in User mode, for maximum stability? In Windows, at least, the answer is it depends. Device drivers

    grep '^X-Spam-Level' | sort | unique | wc -l

    length . nub . sort . filter (isPrefixOf "X-Spam-Level")

  foo x y = 2 * x + y

  foo = (+) . (2 *)

As the two examples should make clear, point-free style is sometimes natural, and sometimes not, and the example chosen by M. Lai was carefully selected to bias the argument in favor of point-free style.

Often, after writing a function in pointful style, I get the computer to convert it automatically to point-free style, just to see what it looks like. This is usually educational, and sometimes I use the computed point-free definition instead. As I get better at understanding point-free programming style in Haskell, I am more and more likely to write certain functions point-free in the first place. For example, I recently wrote:

        soln = int 1 (srt (add one (neg (sqr soln))))

        soln = int 1 ((srt . (add one) . neg . sqr) soln)

        soln = (int 1 . srt . add one . neg . sqr) soln

        soln = fix (int 1 . srt . add one . neg . sqr)

Sometimes I opt for an intermediate form, one in which some of the arguments are explicit and some are implicit. For example, as an exercise I wrote a function numOccurrences which takes a value and a list and counts the number of times the value occurs in the list. A straightforward and conventional implementation is:

        numOccurrences x []     = 0
        numOccurrences x (y:ys) = 
                if (x == y) then 1 + rest
                else                 rest
            where rest = numOccurrences x ys

        numOccurrences x = length . filter (== x)

        numOccurrences x...
  

There’s a Zizek essay on “Tolerance” up in Critical Inquiry‘s ‘rough cuts’ sections.

I’m not done yet, and it isn’t all bad - but it isn’t good. For example, there’s this:

The main feature of cogito is its insubstantial character: “It cannot be spoken of positively; no sooner than it is, its function is lost.” Cogito is not a substantial entity, but a pure structural function, an empty place - as such, it can only emerge in the interstices of substantial communal systems. The link between the emergency of cogito and the disintegration and loss of substantial communal ...

OK. Cut. That’s rough enough.

I’ve received an email informing me of the emergence of a new blog devoted to Critical Code Studies:

Announcing the launch of a new collaborative blog titled Critical Code Studies . The blog is dedicated to exploring interpretations of computer code within cultural contexts. Rather than focusing primarily on making code function or even the pursuit of “beautiful” code, critical code studies brings in critical theory to examine the ways in which the lines of code reflect, shape, and reproduce our culture including aspects of class, gender, race, sexuality. These criticisms include both the context for the code’s creation and the ways in which it circulates in culture. Rather than one specific lens, CCS names a growing collection of methodologies for making/finding meaning in code.

I sent the email to some friends in the software business and one of them, Richard Fritzson, pointed me to the Wikipedia entry on Conway’s Law:

Conway’s Law is an adage named after computer programmer Melvin Conway, who introduced the idea in 1968. It concerns the structure of organizations and the corresponding structure of systems (particularly computer software) designed by those organizations. In various versions, Conway’s Law states:

* Organizations which design systems are constrained to produce designs which are copies of the communication structures of these organizations.

* If you have four groups working on a compiler, you’ll get a 4-pass compiler.

Or more concisely:

* Any piece of software reflects the organizational structure that produced it.

While I tend to be skeptical of any enterprise whose name takes the form “Critical X Studies,” where X is the domain under investigation, there’s certainly room to look at the cultural production of computer code and the styles of computer languages and programs. 

Starting a company is an exciting, frustrating, and sometimes rewarding endeavor. I've done four startups, founding two. I've been through IPOs, acquisitions, near acquisitions, and the Venture Capital Nuclear Winter of 2001-2003. This talk covers some of the lessons I've learned along the way. I'll talk about raising money, spending money, and some opinions on how to build and release software in a Web 2.0 world.

Adobe's Portable Document Format is so advanced it makes you wonder why anyone bothers with primitive HTML. It's a completely vector-based layout format, both display and resolution independent. With PDF, you sacrifice almost nothing compared to traditional book and magazine layouts except the obvious limitation of resolution. Here's Kevin Kelly extolling the virtues of PDFs:

A PDF is able to retain the highly evolved grammar, design and syntax that one thousand years of bookmaking has attained. Because of the idiosyncratic way web browsers work, designers do not have full control of what you as a reader see on the web. The web page, including its fonts, fonts sizes, and placement of material and size of the window, partly depends on the viewer's preferences. In my experience as a reader, a web designer, and a book designer, the reading experience on paper -- and PDFs -- is much more refined and elegant. As a publisher and designer I can direct the flow of attention with better tools (font choices, rules, lines, columns) and better control. The benefit to me as a reader is that this sophisticated design translates into increased clarity, smoothness, comprehension, and enjoyment.

But I have a problem with PDF files.

1. Every time I link to a PDF, I have to tag the link (pdf) to indicate that the hyperlink will whisk you away, not to another web page as you might expect, but to a strange, otherworldly out-of-browser experience.
2. Links to PDF files assume the user has a PDF viewer installed. Do they? And how will the link be handled? As in situ navigation, presenting the user with a weird new set of PDF controls? Or as an undesirable popup window? Browser support for PDF is so weird there are entire PDF add-ons to deal with it.
3. The layout better be mind-blowingly good to justify the use of the PDF format. For most of the PDFs I encounter, the information could have been presented in HTML and CSS markup with almost no aesthetic loss at all. The "refined, elegant, sophisticated design" offered by PDF is often wasted.
4. You might argue that PDFs make sense as a secondary, print-optimized version of existing HTML content. But why not stick to one version of the content? Why repeat ourselves? Do we really want to maintain two different versions of the same content?

I'm not the first person to note the usability problems of PDF, but I consider this a classic case of worse is better. The advantages of PDF...

Summary:

My vocabulary here is failing me. "Telling them the story" is not what I want, because the Santa Claus thing is deceptive, and telling stories is not normally deceptive: "fiction" and "lies" mean different things. When I tell Iris the story of the Little Red Hen, there is no presumption that there is an actual, literal Red Hen. Iris might think there is, or not, or might not think about it at all; I don't know which. Ditto Cinderella, or Olivia the Pig, or any other story I tell or read to her. But when people tell their kids about Santa Claus, they present it not as a story, but as a literal truth. They present it in a way that is calculated to make the kids believe there is actually a fat, benevolent, white-bearded immortal, manufacturing toys in a secret arctic workshop. This is no longer mere fiction; it is a lie. So what I want to say is that this lady thought she would be depriving her kids of the magic of Santa Claus by not telling them this lie.

But I really don't want to use the word "lie" here, because it's so pejorative. It makes it sound as though I think badly of this good woman for telling her kids that Santa Claus was real. But I don't, at all. She is generally wise and honest and I respect her. Parents tell their kids all sorts of awful, appalling lies, which upsets me a lot, but this lie is quite benign by comparison, and bothers me not at all.

Let me be perfectly clear: I have nothing, absolutely nothing, against the Santa Claus story. I have an article in progress about how much I hate the way parents routinely lie to their kids, to manipulate them, and this one isn't in the article, because it doesn't even register. It's just for fun, or nearly so.

Santa Claus seems pretty harmless to me. Unlike many of the pernicious lies children are told, Santa Claus is a great story. It would be really wonderful to believe that I would get presents every year because there was a fat guy manufacturing toys at the North Pole. Delightful! And the only thing wrong with it is that it isn't true. Oh well. There are a lot of pretty stories that aren't true.

Anyway, at the time I had this conversation about Santa Claus, Iris was too young to have heard about Santa Claus anyway, and my co-worker asked if I was planning to tell Iris the Santa Claus story.

Now that I've written this article, it occurs to me what she meant to ask, was not whether I was going to tell Iris the story, but whether I was going to tell her that it was true. Having realized that now, my reply seems a lot more obvious in...

(sorry, farnsworth, your headline was too good not to gank)

From John Crowley, Little, Big [amazon]:

“Christmas," said Doctor Drinkwater as his red-cheeked face sped smoothly toward Smoky’s, “is a kind of day, like no other in the year, that doesn’t seem to succeed the days it follows, if you see what I mean.” ...

“I mean,” Doctor Drinkwater said, reappearing beside him, “that every Christmas seems to follow immediately after the last one; all the months that came between don’t figure in. Christmases succeed each other, not the falls they follow.”

“That’s right,” said Mother, making stately progress around. Behind her, like the wooden ducklings attached to wooden ducks, she drew her two granddaughters. “It seems you just get through one and there’s another.”

“Mmmm,” said Doc. “Not what I mean exactly."

The noetic-noematic structure of Christmas - its peculiarly trans-annual protentive-retentive character - is an appallingly neglected subject in contemporary phenomenology. And grabbing people by the lapels and barking this intelligence in their face doesn’t seem to help. There is no reasoning with a certain class of thinker.

I suppose the tree will have to come down today. I’m going to be dull and say: I had a really great Christmas season this year, very wisely spent it by not blogging too much. Indeed, neither writing nor reading much. I feel considerably restored and am expectant of a Happy New Year. And a Happy New Year to you, too.

Iris pointed out a mural she liked, and I observed that there was construction on the adjacent vacant lot, which is likely to mean that the mural will be covered up soon by the new building. I mentioned that my favorite Philadelphia mural of all had been on the side of a building that was torn down in 2002.

Iris asked me to tell her about it, so I did. It was the giant mural of Harriet Tubman that used to be on the side of the I. Goldberg building at 9th and Chestnut Streets. It was awesome. There was 40-foot-high painting of Harriet Tubman raising her lantern at night, leading a crowd of people through a dark tunnel (Underground Railroad, obviously) into a beautiful green land beyond, and giant chains that had once barred the tunnel, but which were now shattered.

It's hard to photograph a mural well. The scale and the space do not translate to photographs. It looked something like this:

Here's a detail:

Anyway, I said that my favorite mural had been the Harriet Tubman one, and that it had been torn down before she was born. (As you can see from the picture, the building was located next to a parking lot. The owners of the building ripped it down to expand the parking lot.)

But then Iris asked me to tell her about Harriet Tubman, and that was something of a puzzle, because Iris is only three and a half. But the subject is not intrinsically hard to understand; it's just unpleasant. And I don't believe that it's my job to shield her from the unpleasantness of the world, but it is my job to try to answer her questions, if I can. So I tried.

"Okay, you know"...

So. I spent a week helping a friend through sort of a rough time. Then somehow I got interested in poker (of all things!) and geeked out on all the math and logic that goes into winning that game consistently, and that became an obsession. When I realised I'd lost a month to it, I spent a week or two just catching up, only to head off to texas for ten days to visit my family. Somewhere in there, I spent two days helping to rebuild a bridge.

I've been craving those personal test cases. Some of the individual tests don't seem all that important in retrospect, but the combined effect made for one of the most productive periods I've had in a long time. Certainly the most clear-headed one.

Looking back a little further, I still think there's something to be gained from having big year-long goals as well as tiny daily habits. Otherwise, the daily checklist is just a well-tuned engine purring along in a car that's stuck in neutral. What I really want is to apply that discipline toward the pursuit of some larger goal.

So what's my goal? I've realized that I tend to make a lot of potential futures in my imagination, and they're all interesting and fun to think about, and it's more fun daydream about ten cool ideas than to set aside nine of them and dedicate myself to only one. Or even to just decide on the order in which I'll tackle them.

But that's what I need to do, and so that's what I'm doing today.

My plan is to... Well, make a plan.

Since time is linear and there's only one of me, a good plan should read like an imperative program. Work on one thing, then the next, and so on. But if you're talking about months, then you HAVE to multi-task. I mean you can't work on fitness for 3 months, and then stop that and work on email. There's on going work to be done.

I think a checklist is a good tool for balancing multiple plans. It gives you a tool to manage concurrency. But even so, there's only so many threads you can run without bogging down the processor (stressing out and being ineffective).

Basically, the point is to balance a set of good habits, and then have one big thread to handle bigger projects one at a time.

It occured to me that I would be incredibly effective if I could just write a little program to tell me what to do - or at least where to focus - on a moment by moment basis. Something with a default schedule for the day that guided me through breaking my goals down into tasks and then organizing and implementing those tasks... Reminding me to start cooking healthy food before I get hungry and go searching for a snack. Checking my email in the background and only notifying me of new messages between tasks. That kind of thing.

I want to talk more about this concept of self-automation, but I'm already starting to ramble here. I really just wanted to check in since I hadn't written in so long. I'm going to post a couple big goals for the year either today or tomorrow, and also...

When we call something a scripting language, we’re primarily making a linguistic and cultural judgement, not a technical judgement.

For a given dimension X, different scripting languages make different choices, set the knob at different locations.

• You can’t even think about X!
• There’s only one way to do X!
• There’s more than one way to do X!
• There are too many ways to do X!

I started out as a BASIC programmer. Some people would say that I’m permanently damaged. Some people are undoubtedly right.

I had a college buddy I did pair programming with. We took a compiler writing class together and studied all that fancy stuff from the dragon book. Then of course the professor announced we would be implementing our own language, called PL/0. After thinking about it a while, we announced that we were going to do our project in BASIC. The professor looked at us like were insane.

Nobody else in the class was using BASIC. And you know what? Nobody else in the class finished their compiler either. We not only finished but added I/O extensions, and called it PL 0.5. That’s rapid prototyping.

Is LISP a candidate for a scripting language? While you can certainly write things rapidly in it, I cannot in good conscience call LISP a scripting language. By policy, LISP has never really catered to mere mortals.

And, of course, mere mortals have never really forgiven LISP for not catering to them.

I’ve always admired Tcl’s delegational model of semantics. But it fell into the same trap as LISP by expecting everyone to use the One True Syntax. Speaking of the One True Syntax: I don’t really know much about Python. I only stole its object system for Perl 5. I have since repented.

PHP takes the worse-is-better approach to dazzling new depths

I read [the word "text"] from a postmodern perspective. Of course, the term Postmodern is itself context-sensitive. Some folks think Postmodernism means little more than the Empowerment of the Vulgar. Some folks think the same about Perl. But I take Postmodernism to mean that a Text, whether spoken or written, is an act of communication requiring intelligence on both ends, and sometimes in the middle too. I don’t want to talk to a stupid computer language. I want my computer language to understand the strings I type.

So I went to fix that, and then I couldn't decide which sample slides to show. And I haven't given the tutorial for a couple of years, and I have an upcoming project that will prevent me from giving it for another couple of years. Eh, figuring out what to put online is more trouble than it's worth. I decided it would be a lot less toil to just put the whole thing online.

The materials are copyright © 2004 Mark Jason Dominus, and are not under any sort of free license.

But please enjoy them anyway.

I think the title is an accidental ripoff of an earlier class by Damian Conway. I totally forgot that he had done a class on the same subject, and I think he used the same title. But that just makes us even, because for the past few years he has been making money going around giving talks on "Conference Presentation Aikido", which is a blatant (and deliberate) ripoff of my 2002 Perl conference talk on Conference Presentation Judo. So I don't feel as bad as I might have.

Welcome to my ~/bin complete slides and other materials.

I hereby wish you a happy new year, unless you don't want one, in which case I wish you a crappy new year instead.

• Marc Battyani
  HPC Platform
  Neuilly-sur-Seine, France
  Lisp-based supercomputing
• Juan José García-Ripoll
  Madrid, Spain
  ECL - more than an Embeddable Common Lisp
• Jeremy Jones
  Clozure Associates
  Boston, MA, USA
  InspireData - how it was written in Lisp
• Kristoffer Kvello
  Selvaag Bluethink
  Oslo, Norway
  House Designer - using Knowledge Based Engineering and Lisp to automatically design buildings
• Nicolas Neuss
  University Karlsruhe
  Karlsruhe, Germany
  Femlisp - solving partial differential equations with Common Lisp
• Stefan Richter
  freiheit.com technologies gmbh
  Hamburg, Germany
  Using Common Lisp for large Internet systems
• Kilian Sprotte
  Berlin, Germany
  PWGL - an environment for sound synthesis and computer aided composition
• Kenny Tilton
  Wall, NJ, USA
  "Why we should not be here and what we should be doing instead" - a rant on the state of Lisp and Lispniks touching on Algebra software, Lisp libraries, Open Source, Cello, Cells, and somewhere along the way introducing Triple-Cells, animated data modelling with persistence for free

The Dunning-Kruger effect is the phenomenon wherein people who have little knowledge think that they know more than others who have much more knowledge.

Privacy has always been a concern on the internet. But as more and more people let it all hang out on the many social networking websites popping up like weeds all over the web, there's much more at risk. Every other week, it seems, I'm reading about some new privacy gaffe. Last month, it was Facebook's Beacon opt-out policy; this week, it's Google Reader sharing private data. The privacy problems just keep piling up as more people tune in and turn on.

Nearly a decade ago, Sun Microsystems CEO Scott McNealy snapped out a warning to the worriers of the Internet Age: "You don't have any privacy. Get over it." McNealy's words look more prescient every year. In 2006, AOL unwittingly divulged the personal lives of 650,000 customers by publishing their search histories as research data. Despite AOL's attempts to anonymize the info, the New York Times quickly outed a 62-year-old lady in Georgia whose searches revealed her dog was wetting the upholstery. The Justice Department has subpoenaed Google, Yahoo!, MSN, and AOL for lists of search queries. More recently, Facebook employees were caught reading the customer logs.

Nothing warms the cockles of a user's heart quite like the tender mercies of your friendly neighborhood CEO. That privacy stuff you're so worried about? Get over it! You might wonder if Mr. McNealy has the same glib attitude towards the privacy of himself and his own family. Only criminals have stuff to hide, right? Here's Bruce Schneier's take on the value of privacy:

Last week, revelation of yet another NSA surveillance effort against the American people has rekindled the privacy debate. Those in favor of these programs have trotted out the same rhetorical question we hear every time privacy advocates oppose ID checks, video cameras, massive databases, data mining, and other wholesale surveillance measures: "If you aren't doing anything wrong, what do you have to hide?"

Some clever answers: "If I'm not doing anything wrong, then you have no cause to watch me." "Because the government gets to define"...

/*
 *  call-seq:
 *     array.collect {|item| block }  -> anarray
 *     array.map     {|item| block }  -> anarray
 * 

 *  Invokes block once for each element of self. Creates a 
 *  new array containing the values returned by the block.
 *  See also Enumerable#collect.
 * 

 *     a = [ “a”, “b”, “c”, “d” ]
 *     a.collect {|x| x + “!” }   #=> [“a!”, “b!”, “c!”, “d!”]
 *     a                          #=> [“a”, “b”, “c”, “d”]
 */
static VALUE
rb_ary_collect(ary)
    VALUE ary;
{
    long i;
    VALUE collect;

    if (!rb_block_given_p()) {
    return rb_ary_new4(RARRAY(ary)->len, RARRAY(ary)->ptr);
    }

    collect = rb_ary_new2(RARRAY(ary)->len);
    for (i = 0; i < RARRAY(ary)->len; i++) {
    rb_ary_push(collect, rb_yield(RARRAY(ary)->ptr[i]));
    }
    return collect;
}

class Object
  # unfold takes a "seed" argument and a incrementor. It returns an array. The first element of the array is the
  # seed, every subsequentelement is the result of applying the incrementor to the previous element.
  # so in pretentious quasi-math: result[n] = incrementor(result[n-1]).
  # the array ends when the incrementor returns nil, so unfold(0) { |n| n+1 } is a bad idea in Ruby
  # to add terminating conditions, use if not logic, because false does not terminate unfold.
  #
  # example: 10.unfold { |n| n-1 unless n == 1 }.inspect => [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
  # example: 10.class.unfold(&:superclass).inspect => [Fixnum, Integer, Numeric, Object] # using Symbol#to_proc
  #
  # See also: NilClass#unfold
  def unfold...