Wednesday, February 12, 2003

A digression on the scientific method
I'm sure you've all seen this in some form, but I like laying it out clearly.

Suppose I have two coins. One of them is a two-headed coin; the other one is a normal coin. I choose one of them at random and flip it; it comes up heads. What is the chance that it is the two-headed coin? Well, this is a pretty simple exercise in using Bayes' Theorem. The total probability of getting heads is 3/4, and the total probability of picking the two-headed coin and getting heads is 1/2 x 1 = 1/2. So, by Bayes' Theorem, the probability of it being the two-headed coin given that it came up heads is P(2-headed given heads) = P(2-headed and heads) / P(heads) = (1/2)/(3/4) = 2/3. No problem.

All right, let's move on. I have a coin, and I flip it. It comes up heads. I say, "I have a theory: that this happened because this is a normal coin." My friend comes into the room and says, "Oh yeah? I have a better theory. Your coin came up heads because it was a two-headed coin. And look! You just proved that my theory has a 2/3 chance of being correct." Well, yes and no. If we assume that, a priori, the coin was equally likely to be a regular coin and a two-headed coin, then yes, it's true that the coin has a 2/3 chance of being two-headed. But we have a better knowledge of the a priori distribution than that -- we know that normal coins are far, far more common than two-headed coins, so the probability of it being a two-headed coin is still very small, even given this one piece of information.

But notice the key feature of this: the experiment (such as it is) can't give us a full picture of which hypothesis is more likely without some a priori assumptions about which hypothesis is more likely in the first place.

So, I'll bet you can see where this is headed. I have a coin, and I flip it. It comes up heads. I say, "I have a theory: this happened because this is a normal coin." My other friend walks in, and says, "Well, I have a theory that this happened because invisible angels manipulated the trajectory of the coin to make it come up heads." The scientific method is completely helpless to resolve this dispute; you have to use your own a priori knowledge to adjudicate it. This is where we like to talk about what makes a theory "scientific", but all that really means is setting out an objective framework for deciding what's likely in the first place and what's not. It's a big mess.

Tuesday, February 11, 2003

On the Commodification of A Priori Egalitarian Systems
(Why yes, I am feeling in an academic mood today. How could you tell?)

So, I'm sure you've read this study of the economy of Norrath. (For those of you who haven't: Norrath is the virtual world in the game EverQuest, and this paper is a fascinating analysis of its economy. Possessions in the virtual world are often bought and sold online for real money; you can even establish an exchange rate given these transactions, in which the Norrathian platinum piece comes out as stronger than the lira or yen. But if you haven't, read the article. It's fascinating stuff, and humorously written.) Now, as you might expect, all characters are created equally; everyone starts out as a Level 1 weakling with nothing to his, her, or its name. In EverQuest's many predecessors (note: I've never played EverQuest itself, but I'm familiar with MUDs, the ancestor of MMORPGs like EverQuest), the only way to build up your character was by expending time in the virtual world -- time spent improving your character's abilities, obtaining equipment and money, and forging friendships and alliances with other characters. But now, with the ability of outside wealth to influence a player's ability, one can substitute cold, hard US cash for expenditure of time in the world of Norrath. As Castronova notes, "Unfortunately the equality of opportunity is beginning to erode...It has become possible to start a new avatar and use US currency to instantly endow it with vast virtual riches and expensive equipment." (p. 15) I've seen enough complaints about rich kids buying their way to success to figure that this is an issue which makes people unhappy, and with good reason. (If you want to get all Marxist, you can insert the appropriate rhetoric: the bourgoisie, with their capital -- capital not even acquired within the world of the game! -- can use this capital to take advantage of the labor of the proletariat. Wasn't that fun?)

Now, Sony has attempted to prevent this kind of trading (not, of course, for any kind of socialist utopia reasons, but because they believe -- arguably correctly -- that the game's property is their intellectual property), but although they've tried to stamp out auctions in eBay and Yahoo, it's awfully hard to prevent the black market. Castronova says, "My impression is that the ban has had little impact on trading. Sony, effectively the government of Norrath, is fighting a war of trade restrictions that no government has ever won." (p. 19) The truth is, as long as these commodities have value to people, they will be bought and sold, regardless of what Sony wants to enforce.

It's hard to feel too worked up about this issue, since it is a game I don't play after all (although I suspect I might be a little annoyed if I actually did play the game). But an issue that hits a little closer to home is the Google vs. SearchKing issue. Now, of course I fully support Google; it's hard not to feel that businesses like SearchKing are a little sleazy. Google has always cast itself as the promoter of egalitarianism; their description of PageRank touts itself as relying "on the uniquely democratic nature of the web" and strongly emphasizes that only a page's merit will determine its PageRank. But reading through this article, and then James Grimmelmann's article in LawMeme (another excellent read), brought me to this open letter from SearchKing CEO Bob Massa. The letter, of course, portrays SearchKing as a company just trying to help those struggling little mom-and-pop web sites; you can make your own decisions about just how truthful it is, but Massa makes a very troubling point in his letter: "People are going to start selling PR [PageRank] regardless of what Google does. If there is value in it, someone is going to sell it."

And the simple truth is, regardless of whatever the truth may be about SearchKing's real mission, Massa is right. In the world of Google, a high PageRank is valuable, and, well, if a less-reputable site wants to offer money to a site with a high PageRank to get them to link to them...Google can try to go after the SearchKings of the world, like Sony can go after the obvious auctions on eBay and Yahoo, but on a practical level, there's no way to stop it. You and I might find it distasteful, and Google almost certainly has an interest in quashing it, since it reduces the value of their rankings without any compensation to Google, but that can't stop it from happening. Does this mean that I think PageRank is ultimately doomed? I have confidence that it's currently too impractical to significantly boost one's ranking this way, especially when the alternative of making a higher-quality site is available, but the fact that SearchKing had succeeded in improving the reputation of itself and its clients does indicate that it can be done. The invisible hand is just too powerful in these situations; a black market will always spring up even if the government tries to prohibit commerce in these goods.

Monday, February 10, 2003

J-Lo, and how we know what isn't so
(apologies to Thomas Gilovich for stealing his title, and my readers for inflicting this rhyme, but I couldn't resist)
So, it's a well-known fact that Jennifer Lopez has a large butt. It's been the (ahem) butt of a thousand remarks (the majority unflattering; although I can believe that at least some of them are in a positive spirit, there's certainly a fair amount of meanness in a lot of what I see, too), but they say any publicity is good publicity, and it certainly hasn't hurt her. After all, if you were to walk up to a random stranger on the street and ask them to name you someone with a large butt, they'd almost certainly put her near the top of the list. I could go on about how this is some reflection of how America always wants to find fault in its celebrities, but that's not really my point here.

The point is that the emperor has no ass. That is, if you actually ask anyone reasonable, they'll agree that her butt is by no means larger than average. It might be slightly above the average of Hollywood, but it's hardly large, even taking Hollywood as a norm, much less the American populace, where it's still definitely below average (to state the obvious). Why does this happen, then? Well, it got started out somehow, and people liked to talk about it (for whatever reason), and since no one was particularly interested in arguing the other side (what's the point, after all?), it just spread to the point where, if there's anyone in America who hasn't actually seen J-Lo, they're probably convinced she must have a butt the size of Refrigerator Perry.

Now, in J-Lo's case, this is pretty harmless (and, despite the meanspiritedness, probably beneficial, on the whole). But the way with which something with such a tenuous basis in fact can spread to the point where it becomes accepted as common knowledge, simply by virtue of being constantly repeated, is more than a little alarming.

Tom Tomorrow can tell where I'm headed with this.
Thoughts from the road
As you probably know if you've ever driven on an interstate, usually whenever there's an exit sign on the right, there's a corresponding sign on the left telling you where the continuing freeway goes. "280 San Jose", or whatever. When I was driving in Southern California this weekend, I was inordinately amused when I found myself on 605, and those signs read "605 THRU TRAFFIC". The freeway wasn't actually notable for going anywhere, it was just there to carry traffic. I think there's some kind of deep social commentary to be gleaned from this.

On another note, my luck finally ran out and I got a speeding ticket. Oddly enough, despite my having pondered this very question often while driving, I still was momentarily stymied when the officer asked me if I knew how fast I was going. Part of it was that I actually didn't, since I didn't have my eye on the speedometer at the moment, and part of it was that I was trying to figure out what the best answer was. Finally, I figured that I probably shouldn't say anything over 90, and I wasn't sure anything under 90 was plausible, so I settled on that and hoped it was actually accurate. He seemed to agree, so I guess I was right.