This theoretical paper reevaluates the Piagetian tradition in the study of propositional reasoning. Piaget's assertion that children's logic, prior to the stage of formal operations, is structurally adequate for dealing with objects and their properties, but is inadequate for fully competent propositional reasoning, is challenged on three grounds: (1) the data base from which Piaget's theory about formal reasoning has been developed comes from a scientific task domain with its specific task requirement and associated psychological factors; (2) the theory cannot, a priori, be extended to other propositional task domains, and empirical support for generalizing it has not been provided; (3) findings from adult studies show that adults tend to rely on empiric (rather than propositional) reason whenever it is possible to do so. Therefore, there are interesting similarities between child and adult reasoning which the Piagetian outlook has de-emphasized. A linguistically oriented view on the development of propositional reasoning is proposed, based on the idea that acquiring propositional competence is an achievement of the same nature as acquiring competence in grammar or syntax. The theoretical and methodological consequences of this view are examined. (GO)