Christoph von Sigwart

Christoph von Sigwart (1830-1904) was a German philosopher and logician, known mainly as a representative of psychologism and as one of the forerunners of normative logic. Though he is little remembered today, his work was an important reference for logical theory in the late nineteenth century and influenced later thinkers such as Scheler and Heidegger.

He studied philosophy and theology in Tübingen, his native town, and taught at Blaubeuren from 1859 before returning to Tübingen in 1865. His main work, the Logik, appeared in two volumes between 1873 and 1878. Rather than engaging at length with the theories of his predecessors, he aimed to build a self-contained theory of logic. For Sigwart, logical truth ultimately rests on a feeling of logical satisfaction: when judging whether a conclusion follows, we must trust that feeling, which signals the truth itself. This view drew criticism, including from Charles S. Peirce in his later writings.

His interests also reached ethics, with Vorfragen der Ethik (1886), and the history of philosophy, where he examined the inductive theories of Bacon, Mill and Hume. His legacy lies chiefly in the debate over psychologism and the relation between logic and psychology.