Editing Hermann von Helmholtz (section)

===Sensory physiology===

Helmholtz was a pioneer in the scientific study of human vision and audition. Inspired by [[psychophysics]], he was interested in the relationships between measurable physical stimuli and their correspondent human perceptions. For example, the amplitude of a sound wave can be varied, causing the sound to appear louder or softer, but a linear step in sound pressure amplitude does not result in a linear step in perceived loudness. The physical sound needs to be increased exponentially in order for equal steps to seem linear, a fact that is used in current electronic devices to control volume. Helmholtz paved the way in experimental studies on the relationship between the physical energy (physics) and its appreciation (psychology), with the goal in mind to develop "psychophysical laws".

The sensory physiology of Helmholtz was the basis of the work of [[Wilhelm Wundt]], Helmholtz's student, who is considered one of the founders of experimental [[psychology]]. More explicitly than Helmholtz, Wundt described his research as a form of empirical philosophy and as a study of the mind as something separate. Helmholtz had, in his early repudiation of [[Naturphilosophie]], stressed the importance of [[materialism]], and was focusing more on the unity of "mind" and body.<ref>{{Cite book| title = Making Modern Science: A Historical Survey | author = Peter J. Bowler and Iwan Rhys Morus | publisher = University of Chicago Press | year = 2005 | page = 177 | isbn = 978-0-226-06861-9 | url = https://books.google.com/books?id=LEl3s-wYg10C&q=Helmholtz+materialism++sensory+nineteenth-century+Naturphilosophie&pg=PA177 }}</ref>