 Though some details remain rough, this is still an extraordinary achievement. Bolzano’s approach yields the first logical definition of probability. For the first time deductive logic and inductive logic are united in a global theory and the former appears as a limit case of the latter. It is possible that in his Tractatus 5.15, Wittgenstein took over Bolzano’s treatment of probability, perhaps through the mediation of the 1st edition of the Philosophical Propedeutic of R. Zimmermann (1853). Carnap’s regular confirmation functions, too, are strongly reminiscent of Bolzano’s approach.