Tuesday, January 31, 2012

Howard Marks on Taxing the Rich

I like Howard Mark's writing because it cuts the rhetoric and attempts to look at an issue from multiple angles. In a recent memo, he frets about the increasing use "the rich should pay their fair share" in political circles. "Fairness" may really be a eye-of-the-beholder thing, he argues quite convincingly.

As as example he says about tax deductions:
The drafters called them deductions: provisions that reduce the net income on which  taxes are levied. Critics call them loopholes, suggesting there’s something underhanded  about those provisions. And politicians use the laudatory-sounding term tax incentives to describe tax code provisions that reduce tax revenues in order to encourage certain behavior. It all depends on your point of view.
And later:
As I’ve written before, I was very impressed when, as a young man, I heard an interesting explanation for America’s economic progress relative to Great Britain: “When the worker in Britain sees the boss drive out of the factory in his Rolls Royce, he says ‘I’d like to put a bomb under that car.’ When the worker in America sees the boss drive out of the factory in his Cadillac, he says ‘I’d like to have a car like that someday.’ ”
In recent weeks, much has been made of nation-wide polls which say something like "75% of the people support increasing taxes on the rich" etc. or something similar.

That is such a stupid question to ask/poll.

Sure, as rational self-interested individuals, why wouldn't they? It is a classic case of tyranny of the majority. Despite the superficial difference, it is not completely unlike popular support for banning the hijab in France (which much of the media saw as somewhat bigoted).

PS: I am a card-carrying member of the 99% :). I think the memo is a great read, simply for the nuanced views it presents dispassionately.

Monday, January 23, 2012

Andre Agassi's Open

Andre Agassi's autobiography "Open" (written with Pultizer Prize winning author J. R. Moehringer) tells the story of tennis prodigy forced to hit balls in his backyard by an overbearing father growing up to become world champion.

Despite hating the game.

From the book flap:
From Andre Agassi, one of the most beloved athletes in history and one of the most gifted men ever to step onto a tennis court, a beautiful, haunting autobiography. Agassi's incredibly rigorous training begins when he is just a child. By the age of thirteen, he is banished to a Florida tennis camp that feels like a prison camp. Lonely, scared, a ninth-grade dropout, he rebels in ways that will soon make him a 1980s icon. He dyes his hair, pierces his ears, dresses like a punk rocker. By the time he turns pro at sixteen, his new look promises to change tennis forever, as does his lightning-fast return. And yet, despite his raw talent, he struggles early on. 
He played tennis for 21 years, winning 8 Grand Slam titles (7th on all time list), and is one of the very few people who have won all the four Slams (and the Olympic Gold at Atlanta '96). For some time, he was the oldest #1 player, and has an incredible record at the Davis Cup. In the book, he paints a fascinating portrait of key matches in his career, many of which I remember watching when I was in high school. 

Reading the book was like watching the director's cut version of a movie. You've seen it before, but now you see it again with new eyes.

His metamorphosis as an individual, from a brash, nonconformist, expletive-spewing American with funny hair to a composed, Zen-master with no hair, happened in front of a camera.

The best part of the book, in a very gossipy sort of way, is the insider's view of other tennis players that it affords (however colored). We learn about Connors being an incorrigible prick, about Borg being an amazingly gracious man. We find out that Agassi never got along with Boris Becker (his first "coach" went on to become BB's trainer), and was annoyed by Michael Chang pointing to the sky upon winning (as if God took sides in a tennis match). We understand his love-hate relationship with Pete Sampras, who always seemed to have Agassi's number.

Overall, it is a very nice read (it is rated nearly 5-stars on Amazon).

As I said before, it is a story of "growing up" - albeit under a spotlight. A particularly poignant line in the book (which could as well be a summary of his life so far), is when he says people confused his "self-exploration as self-expression."

Wednesday, January 18, 2012

Foxconn on This American Life

This American Life, hosted by Ira Glass, is one of my favorite public radio programs. A recent episode, entitled "Mr. Daisey and the Apple Factory" (audio), featured an excerpt from Mike Daisey's production "The Agony and Ecstasy of Steve Jobs".

Mike Daisey, a self-proclaimed Apple fanboi, describes his journey to Shenzhen (which depending on how you count may be China's third biggest city) and into Foxconn - the maker of a number of Apple products.

He is a gifted story-teller. He takes an inherently dark and sad subject and makes it into something humane, funny, poignant, and inspiring.

For those familiar with the format of This American Life, "Act II" is called "Act I", and does some fact-checking of Mr. Daisey's claims.

PS for Jan 18, 2012: You may have learned by now that pressing the *Esc* key when the wikipedia blackout page appears, takes you to the article.

Monday, January 16, 2012

Education and Finland

Here's an interesting take on the success of the Finnish education model: What Americans Keep Ignoring About Finland's School Success.
Compared with the stereotype of the East Asian model -- long hours of exhaustive cramming and rote memorization -- Finland's success is especially intriguing because Finnish schools assign less homework and engage children in more creative play.

... Americans are consistently obsessed with certain questions: How can you keep track of students' performance if you don't test them constantly? How can you improve teaching if you have no accountability for bad teachers or merit pay for good teachers? How do you foster competition and engage the private sector? How do you provide school choice?

The answers Finland provides seem to run counter to just about everything America's school reformers are trying to do.
 Worth a read.

Friday, January 13, 2012

Feynman and Why

As a father of a curious three-year old, I know how hard it is to answer "why" questions, beyond a certain point. Just recently, I had the following conversation with my daughter.

Her: "Why is the cow eating with her mouth?"
Me: "Because she does not have any hands."
Her: "Why does the cow not have hands?"
Me: "Hmmm. Because God did not give her hands." (I shamelessly invoke God all the time)
Her: "Why did God not give her hands?"
Me: "I don't know. Go ask God!"

I bumped into the following Feynman video, in which an interviewer asks him "why do magnets attract/repel each other?" Feynman goes on about how difficult it is to answer such why questions without a framework.

Worth a watch!

Tuesday, January 10, 2012

Hard Work versus Intelligence

I am currently reading Jonah Lehrer's fascinating book "How We Decide". If the rest of the book lives up to the three chapters I have read so far, I will recommend it enthusiastically.

In chapter 2, there is an intriguing discussion of the role of mistakes in the learning process, that are potentially relevant in an academic setting (apparently, Neils Bohr once remarked that an expert was a person who had committed all the mistakes possible in a narrow field).

The whole idea is that mistakes aren't things to be discouraged, but rather they should be "cultivated, and carefully investigated". Lehrer talks about a series of experiments performed by Stanford psychologist Carol Dweck on the correlation between future performance and quality of praise.

A bunch of fifth-graders  students were given a relatively easy test. Half the kids were praised for their intelligence ("you must be smart at this"). The other half were praised for their effort ("you must have worked really hard").

These kids were allowed to choose the level of difficulty of their next exam. The first choice was described as hard, but educational, while the other was described as being similar to the one they had just taken.  

90% of the kids praised for effort chose the harder test, while a majority of the kids praised for intelligence picked the easy test. They shunned the risk of making mistakes. This aversion can seriously inhibit learning.

Dweck then gave all the kids yet another test. This one was really really hard. In fact, it was written for eighth-graders. Dweck wanted to see how kids respond to the challenge. The "effort" kids got very involved, and tried to tease the test apart, while the "intelligent" group got easily discouraged.

After the test she asked the two groups of students to make a further choice. They could look at the exams of kids who did better than them, or worse than them. The "intelligence" kids almost always chose to bolster their self-esteem by comparing themselves with someone who had done worse. The other cohort were more interested in the higher-scoring exams - "trying to understand their mistakes, to learn from their errors , to figure out how to do better."

She was not done yet.

She gave one final "exit" exam, which was supposed to be similar to the initial test. The "intelligent" group saw their scores drop by 20% on average, while the other group improved by 30%.

As a teacher and parent, this is really important practical stuff. In fact here (pdf) is a relatively recent article on how to raise smart kids by Dweck.

Saturday, January 7, 2012

Scientific Computing: Interactive Modules

Michael Heath and company present a bunch of educational Java modules relevant to Scientific Computing. They are fun to play around with in a browser.

As an interesting side note, we used the book on which many of the modules are based, in our Algorithms 1 undergrad class.

Tuesday, January 3, 2012

Mathematica Integral Fun

Consider the evaluation of the integral of 1/r between -1 and 1, in Mathematica.
  • The function f(r) = 1/r has a discontinuity at r = 0.
  • The indefinite integral of 1/r is simply log(r), which is real for positive "r", and is complex for -ve "r", and goes to negative infinity as r approaches zero.
  • One might be tempted to think that getting definite integrals is easy if one knows the indefinite integral
  • Not so fast. Discontinuties can complicate things!

Let us go back to the integral of f(r) between -1 and 1. From the symmetry of the figure it may be apparent that f(r) is an odd function, and the area under the curve (or the integral) should go to zero.

If we try to use Mathematica to integrate it with Integrate[f,{r,-1,1}], it complains that the integral does not converge.

We say, hmmm. Why don't we simply try to substitute the limits in the indefinite integral:
The answer makes sense since Log[1] = 0, and Log[-1] = i * pi, but is clearly not the correct answer?

The reason for this is that the First Fundamental Theorem of Calculus requires the antiderivative to be continuous over the range of integration, and from the second plot above, it is clear that this condition is violated.
So how do we figure this thing out? We could isolate the discontinuity by integrating close to zero (using "epsilon"), and perhaps take the limit later.

This gives the expected answer of zero.