Peirce in the Long Run: Remarks on Knowledge a Ulteriori

Knowledge a priori has an important role in rationalistic schools: it pre-establishes truth in order to justify a system of correlated ideas. Empiricism usually concerns knowledge a posteriori, for experience itself is what we have actually known. Peirce’s probabilistic approach to science was based on necessity in the long run but it has no clear place in the categorization of knowledge either as a priori or as a posteriori. This deficit should be overcome by introducing a new category — synthetic knowledge a ulteriori, defined as what is known about an indefinite number of cases but not about isolated instances.