"Impossibility, theorems"haverecently appearedin the AIliterature whichhavebeeninterpreted as forbidding truth-functional uncertainty calculi. Such"logicist" calculi do in fact exist. For example, case-based reasoningprinciplesentail a truth-functionalprobabilityagreeingschemewhosestrengths andweaknessesare not so different fromthoseof the usualbelief representation methods.Noclaim is madethat belief modelingshould be conductedexclusivelyalongIogicist lines, but a nontrivial commongroundof intuition does exist beneath Iogicismandits alternatives.