:To further the analogy, A might then go on to argue that his paper is a theorem, by adopting the following definitions: 
 :#"Baseball" means Major League Baseball. 
 :#Only games that count towards a team's standing in its league or division count. 
 :#No league that has been involved in a player lockout within the preceding fifteen years qualifies as "baseball". 
 :These "prove" A's case as follows: 
 :*They exclude minor leagues, little league, non-league games etc., even if major league players are present.  Most people would see this as reasonable. 
 :*They exclude special exhibition games, such as the Baseball Hall of Fame game.  Most people wouldn't care much. 
 :*They exclude pre-season games, which many baseball fans follow avidly and would expect to be included. 
 :*They exclude the All-Star Game, which nearly all fans would expect to be included 
 :*They exclude the World Series.  This would astonish most people. 
 :*They exclude all play since 1994 until at least 2010.  Since interleague play during the regular season began in 1997, the theorem is safe.  Most people would see this as a crock. 
 :A could, and probably would, piously intone that he is could have defined "X-ball" and no one would object, but of course the entire interest of his paper arises because people like "Baseball", and he has a responsibility to use the term as normally employed or else qualify it.  "Until 1997, MLB did not involve regular-season interleague play," is a far better way to communicate the idea.