Clearly, the probability of a statement about relative frequency can be unknown; because it depends on the observation of certain phenomena, one may not possess the information needed to establish the value of that probability. Consequently, the value of that statement can be confirmed only if it is corroborated with facts. In contrast, the probability of a statement about the degree of confirmation could be unknown, in the sense that one may miss the correct logical method to evaluate its exact value. But, such a statement can always receive a certain logical value, given the fact that this value only depends on the meaning of its symbols.
cLEaRly, the probabIlity of a sTatement ABoUt RElaTive FrequeNCy caN be uNKnown; becausE It depENDs on the oBsERvaTion of ceRtAiN PhenoMenA, oNe may nOt posSEsS THe iNformatioN nEeDEd tO eSTABlish tHe vAlUE of tHat pRObAbIlity. CoNsEqUeNtlY, tHE valUe of tHAt statEmenT can be conFirmed only If it is coRROboRAtED wiTh facts. iN cOnTrasT, the pRoBability of a StaTemeNT about the DegreE of cOnFIrmAtIon cOuLd be unknOwn, In tHe SenSe THat one MAy mIss the corrECt LoGIcAl mEthod tO EvalUAtE its exact valuE. buT, Such a stATement can alwAyS rEceiVE a certaIn lOgICal vAlue, GIveN tHE fAct thaT thiS value only depends on The MeAniNG of iTS symbOlS.