2024-2 Frege and Russell(A) One of the main differences between the Principles Era (1900-1908) and the Principia Era (1909-1917) is that only the former adopted the ontology of propositions while the latter abandoned it. In other words, there are no propositions in the Principia. This requires the meticulous and subtle reading of Russell’s works from the Principles Era, since the notation Russel..
