Whoever, in the pursuit of science, seeks after immediate practical utility may rest assured that he seeks in vain. — Herman von Helmholtz’ Academic Discourse (Heidelberg 1862)

August 31st is the birthday of Herman von Helmholtz (1821 - 1894). Von Helmholtz invented inventor of the ophthalmoscope, the tool that physicians (or anyone who has one) use to look into the eye, to look at the retina. Holding this up and squinting into a patient’s head, it sometimes feels like I’m looking for the patient’s mind, which is curiously apt.

Von Helmholtz was interested in oscillations, in sound waves and light waves. He invented his “resonator” that was able to identify various pitches in a pure sine wave containing several tones. He then showed that different combinations could mimic vowel sounds. Alexander Graham Bell, incapable of reading the original German manuscript of von Helmholtz’ work, misconstrued the scientific diagrams. And, in attempting and failing to reproduce what he thought von Helmholtz had accomplished, Bell’s experiments led to the invention of the telephone.

von Helmholtz also wrote a book on optics, Handbook of Physiological Optics (Handbuch der Physiologischen Optik) that investigated empirically based theories on depth perception, motion perception, and color vision, theories that were among the first to imply the existence of an unconscious mind.