Adam Smith said that "the propensity to truck, barter and exchange one thing for another is common to all men, and to be found in no other race of animals.' Smith addressed the mark of the man economical, and there is no denying that this is the peculiar way he acts: clearly, to truck, barter and exchange is to act in a certain way. Austrian economics adopts this way of looking at the realm of economics. It prides itself as a theory of human action. This claim seems ill-founded as long as so important a contribution as Ludwig von Mises's praxeology remains insufficiently understood. In this paper, I address Barry Smith's charge that in praxeology "other core notions, in addition to the concept of action, have been smuggled into and the theory is therefore not purely analytic'. I offer logical proofs of two cornerstone theorems of praxeology, the uneasiness theorem and the scarcity theorem, and thus provide vindication. Also, the findings support Mises's controversial claim that economics is a priori founded in action theory. Thus, Carl Menger's dream to lay foundations to economics and the other social sciences may have come true in the guise of praxeology.