Optics of thought: Logic and vision in Müller, Helmholtz, and Frege
In his writings on logic and the philosophy of mathematics Frege sometimes drew upon similes and metaphors from optics. The author argues that he was knowingly drawing upon a tradition of his time in which logic and optics intersected over questions such as (non-)sensory sources of knowledge. He outlines some of the theories proposed by H. von Helmholtz and Johannes Mueller. A nice footnote about the optician Ernst Abbe, who had supervised Frege's second doctorate, does not tie in with its text on p. 366.
scientific article; zbMATH DE number 1877077