Every athlete knows how to exceed perfection. A steroid here, a hormone there, and you've got the speed, power or stamina to get the gold. The International Olympic Committee (IOC) knows it, too; hence the 1,200 drug tests being conducted at the Turin games.

Thanks to pharmacological data on the Internet and a blossoming generation of chemical hackers, athletes are constantly finding new ways to alter their bodies for advantage. It's a multiplying mess of techniques and designer drugs, with varying degrees of risk, artificiality and manipulation. And the dope cops have done a lousy job of sorting it out.

The bible of Olympic drug testing is the World Anti-Doping Code, written and enforced by the World Anti-Doping Agency (WADA), which was set up by the IOC and various governments in 1999. The code bans a substance or procedure if it meets any two of these criteria: 1) it endangers the athlete's health; 2) it "enhances sport performance"; or 3) it "violates the spirit of sport."

Things that pose clear health risks — very high hemoglobin levels, for instance — are easy calls. But what about things that don't? If all enhancement were forbidden, the code points out, we'd have to ban training, red meat and carbohydrate loading, which would be preposterous. But the code also goes on to say enhancement through gene transfer "should be prohibited as contrary to the spirit of sport even if it is not harmful."

How, exactly, does the spirit of sport forbid gene transfer but not carbo-loading? The code doesn't say. It defines the spirit of sport as "ethics," "fair play," "character" and a bunch of other words that clarify nothing. The definition includes "courage" and "dedication." Doesn't it take more courage and dedication to alter your genes than to snarf a potato?

Human growth hormone appears on WADA's "Prohibited List" of substances and methods, even though the Food and Drug Administration, the National Institutes of Health, and the American Association of Clinical Endocrinologists have vouched, to varying degrees, for its safety. Evidently growth hormone violates the spirit of sport, but stuffing yourself with steaks doesn't.

That's just the beginning of the confusion. The "Prohibited List" tolerates performance-enhancing substances in your body if they're "endogenous" rather than "exogenous." Endogenous, according to the Merriam-Webster Medical Dictionary, means "caused by factors within the body." Exogenous means "not synthesized within the organism." That seems clear enough: You can use what's yours, not what's artificial. But four pages later, the list bans the use of "autologous" blood, which means blood "derived from the same individual." You can use what's yours, except when you can't.

What counts as artificial? Training at high altitude boosts your red blood-cell count; the code says it would be absurd to ban this practice just because it enhances performance. Yet the IOC bars athletes in Turin's Olympic Village from using hypobaric tents, which simulate high-altitude air, and WADA is debating whether to ban them worldwide. Athletes from flat countries say they need the tents to match the conditioning of athletes from mountainous countries.

You'd think that WADA Chairman Richard Pound, who vows on his Web page to "level the playing field," would appreciate that rationale. If Muhammad can't go to the mountain, why shouldn't the mountain come to Muhammad? Instead, Pound rejects the tents as "artificial" and "tacky." He neglects to explain how putting thin air indoors makes it artificial.

Manipulation is another ill-defined target of doping regulators. The list of prohibitions says you mustn't build up hemoglobin or other helpful substances through "chemical and physical manipulation." But if your hemoglobin count gets too high, you're allowed, even expected, to knock it back down through chemical and physical manipulation.

Athletes who busted the hemoglobin limit on their first drug test in Turin have been interviewed while guzzling water to lower their counts for the next test. If water doesn't do the job, doctors point out, you can always bleed yourself; the rules don't seem to preclude it. Between tests, Canadian skier Sean Crooks corrected his hemoglobin level by relocating from the ski training venue in the Alps to the Olympic Village, where he could get low-altitude air. Good thing he didn't do it in a tent. That would have been cheating.

The IOC's doping rules for Turin say WADA's list is "final and shall not be subject to challenge" by athletes. But every year, with little or no explanation, the list changes. Adrenaline and intravenous injections are added; caffeine is removed.

American sledder Zach Lund was bounced from Turin in the first week of the games for failing to notice that Line 3 on Page 3 of Section 5 of last year's changes in the list — "Alpha-reductase inhibitors (finasteride, dutasteride) have been added as masking agents" — made the baldness pills he'd taken and disclosed for six years suddenly verboten.

Even the selective applications change. Last year, substances previously banned "in men only" became illegal for both sexes, while two hormones previously banned in both sexes became illegal only for men.

The list, which also applies to leagues outside the Olympics, differs nonsensically from sport to sport. In billiards, you're allowed two-tenths of a gram of alcohol per liter of blood. In powerboating, you're allowed three-tenths. At a quarter of a gram per liter, you're sober enough to operate a flying death machine but not a cue stick. Often, the limits change for no stated reason. Last year, keeping your alcohol level below a tenth of a gram per liter would get you into skiing but not motorcycling. This year, you can get into motorcycling with the same alcohol level, and you can ski plastered.

The doping cops' predicament is understandable. Performance enhancement is mutating so fast, they're trying to ban what they can and make sense of the rules later. But as we've seen in figure skating and other aesthetic competitions, judges' irrational decisions can discredit the entire Olympics. Maybe that's the nature of art. Science should do better.

William Saletan covers science and technology for the online magazine Slate. He wrote this commentary for The Washington Post.