The other night I watched the movie Butch Cassidy and the Sundance Kid for about the 50th time. It’s a highly entertaining movie – all you have to do is suspend judgment.
As a rules person, the classic scene for me is Harveychallenging Butch to a knife fight (with a knife about the size of a machete) for leadership of the gang. Now Butch is the one who’s always thinking. Stalling for a bit of time he walks an angling path toward Harveyand says, “No, no, not yet. Not until me and Harvey get the rules straightened out.” Harvey, thrown off guard, says (paraphrasing), “Rules?! There are no rules in a knife fight!” Well, exactly! Poor Harvey pays for his moment of verbal clarity with a challenge-ending reminder that, well, there are no rules in a knife fight.
In SBVR terms, Harveyexpressed an advice, a non-rule. If Harvey had been a rule analyst (doubtful) he might have said: “Any action is permitted in a knife fight.” The statement is not a rule because it removes no degree of freedom. Butch, always thinking, complied completely.