The Physiology of the Sense Organs and Early Neo-Kantian Conceptions of Objectivity: Helmholtz, Lange, Liebmann

The physiologist Johannes Müller’s doctrine of specific nerve energies had a decisive influence on neo-Kantian conceptions of the objectivity of knowledge in the 1850s - 1870s. In the first half of the nineteenth century, Müller amassed a body of experimental evidence to support his doctrine, according to which the character of our sensations is determined by the structures of our own sensory nerves, and not by the external objects that cause the sensations. Neo-Kantians such as Hermann von Helmholtz, F.A. Lange, and Otto Liebmann took Müller’s doctrine to have far-reaching consequences for their epistemologies. Over the course of the 1850s - 1870s, these three neo-Kantians, each in his own way, argued that reflection on Müller’s doctrine ruled out a certain conception of the objectivity of knowledge. It ruled out the view that knowledge is objective in virtue of affording us information about objects in a mind-independent external world. This paper traces how Helmholtz, Lange, and Liebmann developed their arguments for this view, and how each developed his own alternative conception of objectivity, according to which objectivity has nothing to do with a mind-independent world. Finally, the paper concludes by considering why these arguments modelled on Müller’s doctrine would have been so powerful against rival post-Hegelian conceptions of objectivity, especially those of scientific materialists like Ludwig Büchner.