 The choices involved in the rules defining logical constants are important. The difference between a conjunction and a disjunction for instance is that in the case of a conjunction, it is the challenger who may choose the conjunct that will be defended, whereas in the case of a disjunction, it is the defender who may choose the disjunct. The notion of choice has a similar importance for the meaning of the quantifiers. The meaning of logical constants, therefore, is not captured only in terms of which propositions are stated or requested: choices are an essential part of the interaction process as they determine the local meaning of expressions.