  Tarski notes that in order for an argument to be an instance of logical consequence it need not be sufficient that all arguments of the same form be arguments where it is not the case that the premises are true and the conclusion false. It is conceivable that one may interpret the non-logical constants of the argument by means of certain objects (individuals, sets, etc.) in such a way that the premises thus reinterpreted become true and the conclusion becomes false, and that nevertheless (some of) those objects not be denoted by non-logical constants of the language that is being considered; in such a case we would not say that the argument is an instance of logical consequence, in spite of the fact that it would satisfy condition (F).