Probabilistic entailment over the classical propositional language is shown to collapse into the classical propositional entailment. Motivated by this result, a probabilistic propositional logic over propositional language endowed with probabilistic assertions is proposed. A sound and weakly complete axiomatization is provided by capitalizing on the decidability of the theory of ordered real-closed fields. This logic is proved to be a conservative extension of classical propositional logic. The talk reports on joint work with Amílcar Sernadas and Cristina Sernadas.