 A recent exchange centers on the influence of Johann Gottlieb Fichte on Helmholtz’s work. Heidelberger (1995) and De Kock (2018) emphasize the influence of Fichtean idealist philosophy on Helmholtz, noting, for instance, that Fichte’s distinction between the “I” and the “not-I” is employed in Helmholtz’s analysis of perceptual experience and in the distinction between subjectivity and objectivity. Hatfield (2018) responds that Helmholtz “rejected Fichtean idealism” and was influenced more profoundly by empirical physiologists of perception, including Müller and Wundt but also Johann Georg Steinbuch and Caspar Theobald Tourtual. Hatfield argues that Helmholtz’s view in 1867 is better understood as “a form modest realism, a kind of structural realism” avant la lettre, “and that, in 1878, he consolidated this position in a way that renders it metaphysical” (2018, 33).