Saturday, March 22, 2008

My Retro Dream Phone

As I have mentioned before, I've been looking for a cell phone that both connects to the internet at reasonably high speed and functions as a pocket computer. So far as I can tell, there is nothing out there that is fully satisfactory for the purpose, indeed nothing much better than my current phone, a Nokia 9300. What I want is a 3G connection, a usable keyboard, and a screen with adequate size measured in both pixels and inches—5" diagonal and vga should about do it. There is at least one phone actually being sold, the Glofiish M800, with 3G, a keyboard and a vga screen, but the screen is less than 3," the keyboard doesn't look very good, and early users report a lot of problems. There is also one phone with 3G and an adequate screen—the HTC Advantage (also sold under other names). It has an odd design (two pieces connected by magnets), is relatively large and heavy and, perhaps most seriously, apparently has a keyboard whose keys don't move.

Thinking about it, it occurred to me that I already have my dream phone. It just needs a few minor improvements.

The Psion Revo was my pda of choice for years and one of my favorite gadgets ever. The screen has a diagonal measure of 5"; the keyboard is, for something its size, amazing. I can actually touch type on it, although not as well as on a standard keyboard. To convert it into my dream phone, all we have to do is:

Replace the screen with a color touch screen about 400x900.

Add the internals of a 3G cell phone.

Add a miniSD slot and a USB connection.

Camera and gps would be nice as well, but not essential.

The result would be bigger than almost most cell phones but still small enough to carry around all the time, as I used to carry my Revo. Assuming that replacing obsolete innards with their more up to date equivalent would leave weight and dimensions unchanged, we have:

157 mm x 79 mm x 17mm
200 g

For a comparison, the Advantage, the only phone I have so far found with an adequate screen, is:

133.5 mm (L) x 98 mm (W) x 20 mm (T) (with keyboard attached)
359 g

So my super Revo would be longer than the Advantage but smaller in overall volume and much lighter.

Of course, the Advantage is an unusually heavy phone. The M800 is smaller than the Revo but, at 178 g, only a little lighter. My 9300 is quite a lot smaller but, at 167 g, only about an ounce lighter.

Unfortunately, Psion exited the consumer market years ago after losing out in competition with Palm; I doubt they will reenter. But the Revo shows what it is possible to do in terms of screen size and keyboard while still keeping overall size and weight down to a tolerable level. Nokia, or Sony, or HTC could presumably license the keyboard design and work out the rest of my dream phone for themselves.

I have said nothing about software. I am reasonably happy with my Nokia 9300 but its successor, the E90, I found unworkable for several reasons, including its different and, in my judgment, much inferior version of the Symbion OS. I have no experience with Microsoft's competing OS. Perhaps, when my phone comes out, it should run Google's Android.

Doing VR Wrong

I recently attended a presentation on what universities are doing with Second Life, a freeform virtual reality environment. A lot of it seemed to involve requiring a class of students to spend an hour or so learning to get around in the virtual world in order to then hold a class there instead of in an ordinary classroom. Since a class in a virtual world has lower fidelity video, lower fidelity audio, and less bandwidth in the form of facial expressions and the like than a class in realspace, it seemed a bit pointless.

It reminded me of my experiences about twenty years ago with educational software. I had written a price theory text and some computer programs to go with it, and gave demonstrations of the programs at economics meetings where my publisher was trying to sell the book. One of the standard questions I got was "how many chapters of the book are on the disk?" My response was that the chapters of the book were in the book, where they belonged. What was on the disk were not chapters of the book but computer programs designed to teach ideas in ways that could be done by a program better than they could be done with text and pictures.

My conclusion at the time was that most "educational software" was bogus—doing things on the computer that could be done just about as well in a book. The motivation was that computers back then were supposed to be exciting, sexy, exotic, so the same student who would be bored reading an explanation of supply and demand in a book would be riveted to the same explanation on a computer screen. I have the feeling that the same thing is happening now with University involvement in Second Life.

Two other points struck me. One was that our university had apparently spent a fair amount of money hiring people to construct its virtual campus on its island in Second Life. But part of the beauty of Second Life is that you don't have to be a professional to do stuff in it. It's a decentralized system where, provided you have access to space to work on--your university's island if you are a student--you can build things. The right way to use it is not to try to replicate a real world classroom with a bunch of student avatars but to give students access to what they need to do things in the virtual world. Such as create a virtual campus.

The other was a comment by one of the presenters that someone in physics wanted to set up physics experiments in the virtual world. It struck me as an oddly perverted idea. What is exciting about doing a physics experiment is discovering that the real world, physical reality, actually obeys the equations physicists use to describe it. Doing the experiment in virtual reality, where the physics professor has programmed the pendulum, billiard balls, or whatever, only demonstrates that the equations obey the equations.

Monday, March 17, 2008

The Purpose of Public Schooling

“A primary purpose of the educational system is to train school children in good citizenship, patriotism and loyalty to the state and the nation as a means of protecting the public welfare.”

Justice H. Walter Croskey, in the opinion holding that California parents do not have the right to home school their children.

The term "fascist" has been overused, and in any case I know nothing about Croskey's views on economics. But I find it extraordinary that he would be willing to explicitly argue that public schools exist largely to indoctrinate children in views the government approves of, with or without the consent of their parents.

I came across the quote in a webbed essay on the decision. It reminded me of an old academic article by John Lott in which he conjectured that the reason schooling was so widely provided by governments was as a way of reducing the cost of controlling their populations, and offered some statistical evidence in support. One version of the paper is available online.

Thursday, March 13, 2008

Krugman Paper: A Serious Comment

Aside from the point about relativity that I mentioned in my previous post, what struck me about the paper was its tone–the implication that economics, like the paper, was about boring and obvious points made with unnecessarily fancy mathematics. That may, for all I know, be an accurate description of economics as taught and practiced at Yale at the time. It is very far from the feel of economics as it was being done, at about the same time, at Chicago.

As it happens, my first published article in economics, written at about the same time, was on almost as odd a topic–an economic analysis of the size and shape of nations, purporting to explain features of the changing political map of Europe from the fall of the Roman Empire to the present. It was, however, intended seriously, and is one of the pieces I'm still proud of. A few years back I came across someone's discussion of the literature on the size of nations. My article was the first one listed and the second, by Jim Buchanan, was about ten years later.

I think it's still an important difference among economists and economics departments, and one that young academics ought to care about. I remember a long time ago commenting to a graduate student at Chicago that it seemed to me that there were a lot of economists who didn't really believe in economics. It was what they did in working hours, not how they thought about the world. His response was that some of his fellow graduate students had noticed that–when visiting other schools.

I was reminded of that incident when visiting one of the colleges my daughter is considering for next year. Wandering around the economics department to get a feel for the place, I spoke with three faculty members–none of whom struck me as an economist in my sense of the term. My daughter, having audited an econ class, commented to me on the fact that a student had made a comment which any economist should have responded to with some version of "that sounds plausible but is wrong because"–a point that would seem obviously right to a non-economist, obviously wrong to an economist. The professor simply let the comment go.

I don't know enough about economics department to say which ones currently are in what category, with two exceptions. Chicago, so far as I can tell, is still a place where economists believe in economics. So, less obviously, is George Mason. One simple test, I suspect, would be to have lunch with members of the department, perhaps also with graduate students, and see what they talk about.

I should add that my point is not that economics is true, although I think it largely is. I am not inclined to take theology very seriously. But if I did take a course in it, I would expect to learn more, and have a more interesting time, if the professor was a believer than if he were an atheist.

Wednesday, March 12, 2008

Paul Krugman's, Interstellar Trade, and Causality Violation

A friend pointed me at a very old paper on Paul Krugman's blog in which the then assistant professor discussed the economics of interstellar trade. The economics is straightforward if unexciting and the writing entertaining, but there is one puzzle. Early in the paper Krugman writes:

“The remainder of this paper is, will be, or has been, depending on the reader’s inertial frame, divided into three sections.”

This implies that the order in time of the sections–whether the order in which they were written or are being read is not clear–depends on the reference frame of the observer. That would be true if the events in question were on a spacelike trajectory, if their separation in distance was greater than the speed of light times their separation in time. It is not true, however, if they are on a timelike trajectory, since a shift from one inertial frame to another does not change the ordering of events that are timelike with respect to each other.

It follows that either the article was written while the author was moving faster than the speed of light or else he expects it to be read by a reader moving faster than the speed of light. This appears inconsistent with the statement a little further down in the article that “travel must occur at less than light speed.”

Because a spacelike four-vector reverses its direction in time with a suitable change in the observer's reference frame, a procedure that sends a message faster than light is, in some reference frame, sending it backwards in time. It follows that the technology used to move the author (or reader) along a spacelike trajectory could also be used to send message from future to past, raising a variety of familiar problems with causality. This may explain why Professor Krugman, in his model, assumed that the planetary futures markets were perfectly informed.

Harald out in paperback

My first (and so far only published) novel, Harald, is now out in paperback. I am happy with it, but the style is definitely not for everyone. For a free sample, a beautiful map, and some other stuff, take a look at the book's web page. Those fond of the spoken word may want to try the podcasts of the early chapters.

My second and very different novel is still sitting at Baen waiting to be read.

Saturday, March 08, 2008

Primaries: Symbol vs Reality

One of the odd features of this year's democratic contest is that everyone continues to talk about who won each state, even though the contest is being conducted under rules that make winning a state a matter of only minor importance.

In a winner take all system, someone who gets 51% of the votes gets all of the delegates, so the outcome of the contest is largely determined by who got a majority in each state. This year, however, the Democrats are conducting their contest under rules that (roughly speaking) give each candidate a number of delegates proportioned to the number of votes he got. So whether a candidate got 51% of the votes or 49% is no more important than whether he got 53% or 51%.

Consider two recent contests. Hillary Clinton won the Texas primary by a narrow margin, and as a result will get 4 more delegates than Barack Obama. Barack Obama won the Wyoming caucus by a big margin—61% to 38%—and will get about four more of the Wyoming delegates than Clinton. One candidate winning the primary of a very small state almost precisely balances the other winning the primary of a very big one—because what really matters this time around is not just whether you won but by how much.

To complicate the matter even more, Texas allocates 2/3 of the Democratic delegates by primary and 1/3 by caucus. The caucus process is complicated and multi-stage, with the result that the actual allocation of delegates will not be known for some months. But it looks, judging by the division of votes, as though Obama will get more of the caucus delegates than Clinton, and may end up with a majority of the Texas delegates despite having lost the primary.

Is everyone but me crazy? Probably not. It seems almost certain that the final decision will be made by the "superdelegates," and the symbolism of who won which state may well affect it.

Friday, March 07, 2008

Perhaps there are libertarians on the left

Roaming the blogs, I came across a link to a surprising and encouraging document. It's an opinion piece in the Wall Street Journal arguing against state restrictions on what sort of health insurance consumers can buy and from where and, more generally, against paternalistic restrictions on freedom of choice. It reads like something that might have been written by a libertarian economist. It ends with:

"Why do we think we are helping adult consumers by taking away their options? We don't take away cars because we don't like some people speeding. We allow state lotteries despite knowing some people are betting their grocery money. Everyone is exposed to economic risks of some kind. But we don't operate mindlessly in trying to smooth out every theoretical wrinkle in life.

The nature of freedom of choice is that some people will misuse their responsibility and hurt themselves in the process. We should do our best to educate them, but without diminishing choice for everyone else."

The author is George McGovern.

Saturday, March 01, 2008

Why Risk Aversion Isn't

Many fields use technical terms that sound self-explanatory and aren't. The result is that many people believe they know what those terms mean—and don't. I am confident that there are millions of people who believe that they understand what the Theory of Relativity says, even if not the mathematical details. The theory says that everything is relative. Surely that is clear enough.

Clear--but almost entirely unrelated to what the Theory of Relativity actually says.

Economics has similar problems with terms such as efficiency and competition. One particularly serious case is risk aversion. It is serious because outsiders are not the only ones who think they understand it and don't.

Risk aversion sounds as though it means aversion to risk; one would expect a risk averse person to avoid dangerous hobbies, a risk preferring person to be drawn to them. It is not true. There is nothing in the definition of risk aversion that implies that a risk averse person is less likely to take up hang gliding or mountain climbing than a risk preferrer.

The definition of risk aversion, as any good textbook that covers the subject will explain, is that a risk averse person, faced with the choice between an uncertain set of monetary payments and a certain payment with the same expected value, will prefer the latter. As that definition suggests, it is a statement not about his taste for risk but about his taste for money.

To see why we would expect people to be risk averse, imagine that you are faced with two possible jobs. One pays you $60,000/year. The other has equal odds of paying you $20,000/year or $100,000 year.

We expect most people to prefer the former job, all else being equal. To see why, imagine that you are shifting continuously from it to the other. You are giving up dollars in the future where you lose the bet—where the salary is $20,000—in order to get dollars in the future where you win the bet. That means that you are giving up (probabilistic) dollars used to buy things you would get as your income increased from $20,000 to $60,000 in order to get (probabilistic) dollars to buy things you would get as it increased from $60,000 to $100,000. As your income increases, you buy the more important things first, so we would expect the gain from getting a dollar at the high end to be less than the loss from losing one at the low end. As this (entirely conventional) exposition shows, risk aversion is simply declining marginal utility of income.

The fact that your marginal utility of income decreases as your income increases tells us nothing at all about how the marginal utility of other things changes as the amount you have of them changes, hence the fact that you are risk averse does not tell us what your attitude will to risk that involves non-monetary payoffs.

Your doctor calls you into his office to give you some very bad news. You have been diagnosed with a disease that, if untreated, will kill you in fifteen years. There is an operation which will let you live thirty years--but half the time it instead kills the patient. You have a choice of a certainty of fifteen years or a fifty/fifty gamble between thirty and zero.

As it happens, the one thing in life you most want to do is to produce and bring up children. Thirty years is long enough to do that; fifteen is not. You grit your teeth and sign up for the operation. You are risk preferring in years of life, because years of life have increasing marginal utility to you. You may be, probably are, risk averse in dollars because dollars have decreasing marginal utility to you.

Risk preference, as economists use the term, is not about risk.

Declining marginal utility, progressive taxes, and fairness

I recently had an interesting online exchange on the subject of taxation. It started with the question of whether and how progressive the U.S. tax system was--to what extent, if you took account of not only the federal income tax but also payroll taxes and state taxes, rich people paid a higher (or lower) fraction of their income than poor people. We mostly skirted the difficult but important issue of tax incidence--not who hands over how much money but who is how much poorer as a result. With that qualification, the conclusion to which the person I was arguing with agreed was that richer people probably paid a larger share of their income in taxes. His calculations suggested that the proportion varied over about a factor of two.

He argued, however, that fairness required greater progressivity. Asked to explain and defend the basis for that belief, he offered the usual argument for declining marginal utility of income, claimed that fairness required equal utility burdens on rich and poor, and concluded that the tax system ought to be highly graduated.

As some of you may realize, he was making a mathematical mistake. His argument, if true, implies that richer people should pay more dollars in taxes than poorer people. But it does not tell us whether they should pay a larger or smaller proportion of their income.

To see that, consider two taxpayers, one with an income of $40,000/year, one with an income of $80,000. Consistent with declining marginal utility of income, assume that the former has a marginal utility of income of two utiles/dollar, the latter of one utile/dollar. Assume a flat tax which collects $4,000 from the poorer taxpayer, $8,000 from the richer. The utility cost of the tax is then 8000 utiles for each--"fair" by the standard of equal utility burden. The utility cost to the richer person of each dollar he pays is half as much--but he is paying twice as many dollars.

Generalizing this example, we can see that if marginal utility of income declines with increasing income less than proportionally--if, say, MU(I)=AI^(-.9)--then equal utility shares imply a regressive tax, while if it declines more than proportionally to income, the same rule implies a progressive tax.

The next interesting question is whether the rule itself makes any sense. I do not see that it does. I can see a philosophical argument for the claim that everyone should end up with the same income, although I am not convinced by it. I can see a utilitarian argument for redistribution designed to transfer income from those with low MUI to those with high MUI, although I can also see utilitarian problems with such a policy.

But a rule of equal utility cost faces two obvious problems. The first is that taxpayers do not all get the same utility benefit from the state, the second that the state does not get the same benefit from all taxpayers.

Consider a program such as social security which collects money and pays out money. Dollars collected from the richer taxpayer probably cost him less utility than dollars collected from the poorer taxpayer cost him. But dollars paid to the richer taxpayers also provide less utility than dollars paid to the poorer. So a rule of equal utility burden means that the poor are getting, in utility terms, a much better deal than the rich.

Next note that if rich and poor are bearing equal utility burdens, the state is getting a much larger benefit from rich than from poor. If one is going to imagine taxation as some sort of exchange between taxpayer and state, shouldn't costs and benefits to both sides count?

Consider the same standard in a private transaction. I offer to mow your lawn. You are much richer than I am, so--as I kindly point out--in order for the payment to cost you as much utility as the mowing costs me, you will have to pay me a hundred dollars an hour.

Assume, I think reasonably, that an hour of work costs each of us the same amount of utility--say ten utiles. You are saving me ten utiles of lawn mowing at a cost to you of ten utiles of lawn mowing. I am paying you (say) ninety utiles of money--money having a high MUI to you--at a cost to me of nine utiles of money. On net I am giving up nine utiles to get ten, you are giving up ten utiles to get ninety. That does not look like a fair transaction.

I should probably add that it is not clear to me that there is such a thing as a fair tax, even if we are willing to separate questions of fairness from questions of justice. But since many people do believe that there is such a thing and that they know about what it would be I find it interesting to try to make sense of the idea. It's a harder project than they may suppose.