Gustav Theodor Fechner (1801–87)

German physicist, philosopher, and psychophysicist. MD, Leipzig, 1822; but never practised. Professor of physics, Leipzig, 1834–9. Suffered a breakdown in 1839, resuming academic life in 1843, when he began to lecture on philosophy, ethics, and the mind–body problem. Founded the discipline of psychophysics, which he described as the scientific study of the functional relations between body and mind. Introduced statistical methods of psychophysical measurement.