What needs to be checked is that the addition of this clause to the antecedent actually guarantees the fourth Aside from generating strengthened beliefs that may look somewhat more natural than beliefs of the form 'I correctly believe that,' the possibility of adding conjuncts that causally or counterfactually imply that I believe that shows that it would be pointless to try to remedy the situation by adding an ad hoc clause somehow exempting beliefs about the subject's own beliefs from the general theory and trying to handle these separately not that such an ad hoc move would have much plausibility (or much chance of success) in any case.