Gustav Theodor Fechner
born April 19, 1801, Gross Särchen, near Muskau, Lusatia
[Germany]
died Nov. 18, 1887, Leipzig, Ger.
German physicist and philosopher who was a key figure in the
founding of psychophysics, the science concerned with
quantitative relations between sensations and the stimuli
producing them.
Although he was educated in biological science, Fechner
turned to mathematics and physics. In 1834 he was appointed
professor of physics at the University of Leipzig. His health
broke down several years later; his partial blindness and
painful sensitivity to light in all likelihood developed as a
result of his gazing at the Sun during the study of visual
afterimages (1839–40).
Pensioned modestly by the university in 1844, he began
delving more deeply into philosophy and conceived of a highly
animistic universe with God as its soul. He discussed his idea
of a universal consciousness at length in a work containing his
plan of psychophysics, Zend-Avesta: oder über die Dinge des
Himmels und des Jenseits (1851; Zend-Avesta: On the Things of
Heaven and the Hereafter).
Fechner’s Elemente der Psychophysik, 2 vol. (1860; Elements
of Psychophysics), established his lasting importance in
psychology. In this work he postulated that mind and body,
though appearing to be separate entities, are actually different
sides of one reality. He also developed experimental procedures,
still useful in experimental psychology, for measuring
sensations in relation to the physical magnitude of stimuli.
Most important, he devised an equation to express the theory of
the just-noticeable difference, advanced earlier by Ernst
Heinrich Weber. This theory concerns the sensory ability to
discriminate when two stimuli (e.g., two weights) are just
noticeably different from each other. Later research has shown,
however, that Fechner’s equation is applicable within the
midrange of stimulus intensity and then holds only approximately
true.
From about 1865 he delved into experimental aesthetics and
sought to determine by actual measurements which shapes and
dimensions are most aesthetically pleasing.
