Fechner, Gustav Theodor

(born April 19, 1801, Gross Särchen, near Muskau, Lusatia—died Nov. 18, 1887, Leipzig, Ger.) German physicist and philosopher who founded the science of psychophysics. He taught at the University of Leipzig (1834–40) but left because of ill health. He developed experimental procedures, still useful in experimental psychology, for measuring sensations in relation to the physical magnitude of stimuli, establishing that, as physical stimulation increases logarithmically, sensation increases arithmetically. Most important, he devised an equation to express Weber's law. His principal scientific work was (1860).

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