[greymule]

It is something of a contradiction, since a good umpire should want to become a better umpire and use every means at his disposal to improve his performance. Therefore, he would need the books. But since B does not follow from A—and many would argue that A is false to begin with—the statement is also a non sequitur. Of course, we probably differ on the meaning of "good" in terms of umpiring.

If all you have is the OBR book, how are you going to call the play in which the runner from 2B, on a ground ball to short, stops in front of F6 to block his vision, and then, with no contact made, continues toward 3B just before the ball bounces up and hits F6 in the nose?

The "good" umpire—the one with only the OBR book and without the interpretive guides—could certainly call the runner out for interference. The "good" umpire could argue that the runner "hinder[ed] a fielder attempting to make a play on a batted ball," that by intentionally positioning himself in the way, he committed an act that "interferes with, obstructs, impedes, hinders or confuses any fielder attempting to make a play." The "good" umpire would follow the book and make the wrong call.

Without the interpretive guides, you're going to call a lot of plays the wrong way. A good umpire does not call a lot of plays the wrong way.

There are dozens more plays—real-life plays, not third-world plays—that require knowledge not in the rule book.