On numerous occasions it has been suggested that the formalism take uncertainty into account by attaching probabilities to its sentences. We agree that the formalism will eventually have to allow statements about the probabilities of events, but attaching probabilities to all statements has the following objections:
1. It is not clear how to attach probabilities to statements containing quantifiers in a way that corresponds to the amount of conviction people have.
2. The information necessary to assign numerical probabilities is not ordinarily available. Therefore, a formalism that required numerical probabilities would be epistemologically inadequate.