Thomas Oberdan


Clemson University

The Sign-Theory of Perception from Helmholtz to Schlick

The transformations of philosophical thought at the turn of the Twentieth Century, and their relations to the scientific developments which stimulated them, pose a daunting challenge to a synthetic understanding of the historical development of the philosophy of science. This challenge is epitomized by the development of the ‘sign theory of perception’, the signature doctrine of Hermann von Helmholtz, as it evolved into the early epistemology of Moritz Schlick. Michael Friedman has argued, in “Helmholtz’ Zeichentheorie and Schlick’s Allgemeine Erkenntnislehre” (Phil Topics 25, pp.