1821 – 1894
Hermann von Helmholtz (1821-1894) was a German physician and physicist whose work spanned physiology, optics, acoustics, electrodynamics, and the philosophy of science. He formulated the principle of conservation of energy, advanced the empiricist theory of perception, and made foundational contributions to the epistemology of geometry and measurement.
Formulated the principle of conservation of energy (1847)
Developed the empiricist theory of perception and unconscious inference
Advanced foundational work on the epistemology of geometry and measurement
Invented the ophthalmoscope for examining the retina
Produced seminal research in physiological acoustics and the perception of tone