§54. Let us recall the kinds of case where we say that "a game is played according to a definite rule".

The rule may be an aid in teaching the game. The learner is told it and given practice in applying it.

—Or it is an instrument of the game itself.

—Or a rule is employed neither in the teaching nor in the game itself; nor is it set down in a list of rules. One learns the game by watching how others play. But we say that it is played according to such-and-such rules because an observer can read these rules off from the practice of the game—like a natural law governing the play.—

But how does the observer distinguish in this case between players' mistakes and correct play?—There are characteristic signs of it in the players' behaviour. Think of the behaviour characteristic of correcting a slip of the tongue. It would be possible to recognize that someone was doing so even without knowing his language.

ELUCIDATION

  1. Looking in detail at the OL use of the word 'rule', we find that there is a disparate collection of uses. There is no justification for the traditional philosopher thinking that hidden in this collection of rags and dust is the golden nugget - the mouse - of the real meaning of 'rule', which is some kind of abstract entity, existing independently of human behaviour.
  2. We can (OL)"Learn the rules of a game by watching it being played" even in cases where players are making mistakes, because there are characteristic patterns of behaviour - not necessarily verbal - which indicate these mistakes. Consider your characteristic hand movement towards your mouth, the sudden frown, and the pursed lips, when you make a slip of the tongue.