The error in baseball is a unique phenomenon in sports—a judgment of the quality of play that makes no difference to the outcome. No other sport, not even a close cousin like cricket, has anything like it. Records of errors are as old as official scoring; the rulebook devotes as many pages to the error as it does to equipment. At each of the 2,430 games played this past season, official scorers, nestled in the press boxes, have devoted considerable intellectual energy and an elaborate casuistry to working out which plays are errors and which aren’t. The statistic’s sublime pointlessness is pure baseball.

“It is, without exception, the only major statistic in sports which is a record of what an observer thinks should have been accomplished,” Bill James, the father of sabermetrics, wrote in his “1977 Baseball Abstract.” “It’s a moral judgment, really.” James, supremely utilitarian, regarded the moral dimension of the error as a failing; it didn’t capture the nuances of what had really occurred on the field. And James was right: as a metric, the error is more or less completely useless.

For baseball, it doesn’t just matter what events transpire but how they transpire. Take one of the most famous errors in history—the ball trickling through Boston Red Sox first baseman Billy Buckner’s legs in the ninth inning of Game 6 of the 1986 World Series, on a slow grounder by Mookie Wilson, of the New York Mets. Had Wilson hit the ball harder or a little to the left—if it had been registered as a hit rather than an advance on an error—the result of the game would not have changed. But baseball’s institutions, not just the fans, consider it essential to record that the game wasn’t won. It was lost. A game without a record of its errors would feel half-forgotten. Just because a statistic is useless doesn’t mean that it’s meaningless.

To enter the world of baseball’s official rulings on the error is to place yourself at the center of sprawling garden labyrinth; it can take days to think your way out. Section 9.12 of Major League Baseball’s Official Baseball Rules begins simply enough:

(1) The official scorer shall charge an error against any fielder:

(a) whose misplay (fumble, muff or wild throw) prolongs the time at bat of a batter, prolongs the presence on the bases of a runner or permits a runner to advance one or more bases, unless, in the judgment of the official scorer, such fielder deliberately permits a foul fly to fall safe with a runner on third base before two are out in order that the runner on third shall not score after the catch.

Notice how the rule, even in its simplest iteration, contains an immediate exception to itself: the fielder who deliberately permits a foul ball. It’s like beginning the statute on robbery by providing a quick example of an act that isn’t robbery.

The comment that follows the rule—baseball rules include commentary, just like the Talmud—confuses rather than clarifies. Slow hands, mental mistakes, and miscommunication between players cannot cause errors. The scorer must believe “the fielder could have handled the ball with ordinary effort.” But how do you define “ordinary effort”? Stephen Utter, a former official scorer for ten years for the Toronto Blue Jays, believes the epistemology of ordinary effort emerges from experience. “You got to see a lot of it to say what is ordinary,” he told me. One of the most charming features of baseball is that there are certain plays that anyone should be able to make, catches a twelve-year-old boy should be able to field. Those ones are obvious. But the definition of “ordinary effort” surely has to be expanded at the élite level. “These are the big boys, these are the professionals, they are supposed to be making plays,” Utter said.

In practice, “ordinary effort” describes, as Bill James wrote, what should have happened. What should have happened in a piece of fielding can have nothing to do with the play of the fielder. Utter offered me a case: The runner hits the ball into the outfield, the fielder bobbles the ball, and the runner advances to second. Is that an error? It depends. “What we would have to look at is—is it a single or is it a double? Or is it a single and advance on an error or on the throw?” The way that the scorer determines whether that bobble is an error or not has less to do with the action of the fielder than with the action of the runner. “Was the runner going all the time? Did he never think about stopping at first? Or was he running and looking at the play and then slowed down a little bit and then took off when he saw the little bobble?” If he paused, noticed the misplay, and ran to second, “That becomes the error.”

It’s like the spooky action at a distance in quantum mechanics: another player’s movement determines the meaning of the fielder’s action. And so far we have really only approached the most basic aspects of the error rule. Rule 9.12 (a)(7) opens a whole other wing to the maze:

The official scorer shall charge an error against any fielder whose throw takes an unnatural bounce, touches a base or the pitcher’s plate, or touches a runner, a fielder or an umpire, thereby permitting any runner to advance.

Errors can happen by accident rather than misplay, and the comment on the rule makes its own unfairness explicit: “The official scorer shall apply this rule even when it appears to be an injustice to a fielder whose throw was accurate.” What’s the reason for the injustice, or, to be more accurate, what the rule describes as the appearance of injustice? “Every base advanced by a runner must be accounted for.”

Rule 9.12(a)(7) means that it is entirely possible to make an error even though you have made the correct play. Utter gave me another example, a local one this time: “Bautista’s in right field. Guy’s tagging up on third, and he throws a laser, a one-bounce laser, to the catcher. And that’s what the catcher wants, a one-bouncer. He doesn’t want it on the fly,” Utter explained. “But that bounce the catcher can’t handle. It gets through him, and if you got to call an error, you got to call it on Bautista—who did exactly what he was supposed to do.” Doing the right thing means risking an error. And making an error can be evidence of the right decision.