 Helmholtz concludes that once natural scientists, physiologists of perception such as himself, entered the philosophical fray, “the path of future investigation was basically prescribed by the inductive methods of the natural sciences” (ibid. 394). Helmholtz’s work in epistemology epitomizes the return to the methods of the natural sciences in the mid-19th century. See Patton (forthcoming) and Schiemann (2013) for more on the background of changes to the approach to the sciences over the 19th century.