Open main menu

Wikipedia β

Gustav Theodor Fechner (/ˈfɛxnər/; German: [ˈfɛçnɐ]; 19 April 1801 – 18 November 1887),[1] was a German philosopher, physicist and experimental psychologist. An early pioneer in experimental psychology and founder of psychophysics, he inspired many 20th century scientists and philosophers. He is also credited with demonstrating the non-linear relationship between psychological sensation and the physical intensity of a stimulus via the formula: , which became known as the Weber–Fechner law.[2][3]

Gustav Fechner
Gustav Fechner.jpg
Born Gustav Theodor Fechner
(1801-04-19)19 April 1801
Groß Särchen (near Muskau), Saxony, Holy Roman Empire
Died 18 November 1887(1887-11-18) (aged 86)
Leipzig, Saxony
Nationality German
Alma mater Medizinische Akademie Carl Gustav Carus (de)
Leipzig University (PhD, 1835)
Scientific career
Fields Psychology
Thesis De variis intensitatem vis Galvanicae metiendi methodis (1835)
Influenced Gerardus Heymans
Wilhelm Wundt
William James
Alfred North Whitehead
Charles Hartshorne
Ernst Weber


Early life and scientific careerEdit

Fechner was born at Groß Särchen, near Muskau, in Lower Lusatia, where his father was a pastor. Despite being raised by his religious father, Fechner became an atheist in later life.[4] He was educated first at Sorau (now Żary in Western Poland).

In 1817 he studied of medicine at the Medizinische Akademie Carl Gustav Carus (de) in Dresden and from 1818 at the University of Leipzig, the city in which he spent the rest of his life.[5] He earned his PhD from Leipzig in 1835.

In 1834 he was appointed professor of physics. But in 1839, he contracted an eye disorder while studying the phenomena of color and vision, and, after much suffering, resigned. Subsequently recovering, he turned to the study of the mind and its relations with the body, giving public lectures on the subjects dealt with in his books. Whilst lying in bed Fechner had an insight into the relationship between mental sensations and material sensations. This insight proved to be significant in the development of psychology as there was now a quantitative relationship between the mental and physical worlds.[6]


Gustav Fechner published chemical and physical papers, and translated chemical works by J. B. Biot and Louis Jacques Thénard from the French language. A different but essential side of his character is seen in his poems and humorous pieces, such as the Vergleichende Anatomie der Engel (1825), written under the pseudonym of "Dr. Mises."

Fechner's epoch-making work was his Elemente der Psychophysik (1860). He starts from the monistic thought that bodily facts and conscious facts, though not reducible one to the other, are different sides of one reality. His originality lies in trying to discover an exact mathematical relation between them. The most famous outcome of his inquiries is the law known as the Weber–Fechner law which may be expressed as follows:

"In order that the intensity of a sensation may increase in arithmetical progression, the stimulus must increase in geometrical progression."

Though holding good within certain limits only, the law has been found to be immensely useful. Fechner's law implies that sensation is a logarithmic function of physical intensity, which is impossible due to the logarithm's singularity at zero; therefore, S. S. Stevens proposed the more mathematically plausible power-law relation of sensation to intensity in his famous 1961 paper entitled "To Honor Fechner and Repeal His Law."

Fechner's general formula for getting at the number of units in any sensation is Sc log R, where S stands for the sensation, R for the stimulus numerically estimated, and c for a constant that must be separately determined by experiment in each particular order of sensibility. Fechner's reasoning has been criticized on the grounds that although stimuli are composite, sensations are not. "Every sensation," says William James, "presents itself as an indivisible unit; and it is quite impossible to read any clear meaning into the notion that they are masses of units combined."

The Fechner color effectEdit

A sample of a Benham's disk

In 1838, he also studied the still-mysterious perceptual illusion of what is still called the Fechner color effect, whereby colors are seen in a moving pattern of black and white. The English journalist and amateur scientist Charles Benham, in 1894, enabled English-speakers to learn of the effect through the invention of the spinning top that bears his name. Whether Fechner and Benham ever actually met face to face for any reason is not known.

The medianEdit

In 1878 Fechner published a paper in which he developed the notion of the median. He later delved into experimental aesthetics and thought to determine the shapes and dimensions of aesthetically pleasing objects. He mainly used the sizes of paintings as his data base. In his 1876 Vorschule der Aesthetik he used the method of extreme ranks for subjective judgements.[7]

Fechner is generally credited with introducing the median into the formal analysis of data.[8]


In 1871 Fechner reported the first empirical survey of coloured letter photisms among 73 synesthetes.[9][10] His work was followed in the 1880s by that of Francis Galton.[11][12][13]

Corpus callosum splitEdit

One of Fechner's speculations about consciousness dealt with brain. During his time, it was known that the brain is bilaterally symmetrical and that there is a deep division between the two halves that are linked by a connecting band of fibers called the corpus callosum. Fechner speculated that if the corpus callosum were split, two separate streams of consciousness would result - the mind would become two. Yet, Fechner believed that his theory would never be tested; he was incorrect. During the mid-twentieth century, Roger Sperry and Michael Gazzaniga worked on epileptic patients with sectioned corpus callosum and observed that Fechner's idea was correct.[14]

Golden section hypothesisEdit

Fechner constructed ten rectangles with different ratios of width to length and asked numerous observers to choose the "best" and "worst" rectangle shape. He was concerned with the visual appeal of rectangles with different proportions. The rectangles chosen as "best" by the largest number of participants had a ratio of 0.62 (between 3:5 and 5:8). This became known as the "golden section" (or golden ratio) and referred to the ratio of a rectangle's width to length that is most appealing to the eye. Carl Stumpf was a participant in this study.

However, there has been some ongoing dispute on the experiment itself, as the fact that Fechner deliberately discarded results of the study ill-fitting to his needs became known, with many mathematicians including Mario Livio refuting the result of the experiment.

The two-piece normal distributionEdit

In his posthumously published Kollektivmasslehre (1897), Fechner introduced the Zweiseitige Gauss'sche Gesetz or two-piece normal distribution, to accommodate the asymmetries he had observed in empirical frequency distributions in many fields. The distribution has been independently rediscovered by several authors working in different fields.[15]


Fechner, along with Wilhelm Wundt and Hermann von Helmholtz, is recognized as one of the founders of modern experimental psychology. His clearest contribution was the demonstration that because the mind was susceptible to measurement and mathematical treatment, psychology had the potential to become a quantified science. Theorists such as Immanuel Kant had long stated that this was impossible, and that therefore, a science of psychology was also impossible.

Though he had a vast influence on psychophysics, the actual disciples of his general philosophy were few. Ernst Mach was inspired by his work on psychophysics.[16] William James also admired his work: in 1904, he wrote an admiring introduction to the English translation of Fechner's Büchlein vom Leben nach dem Tode (Little Book of Life After Death).

Fechner's world concept was highly animistic. He felt the thrill of life everywhere, in plants, earth, stars, the total universe. Man stands midway between the souls of plants and the souls of stars, who are angels.[17] God, the soul of the universe, must be conceived as having an existence analogous to men. Natural laws are just the modes of the unfolding of God's perfection. In his last work Fechner, aged but full of hope, contrasts this joyous "daylight view" of the world with the dead, dreary "night view" of materialism. Fechner's work in aesthetics is also important. He conducted experiments to show that certain abstract forms and proportions are naturally pleasing to our senses, and gave some new illustrations of the working of aesthetic association. Charles Hartshorne saw him as a predecessor on his and Alfred North Whitehead's philosophy and regretted that Fechner's philosophical work had been neglected for so long.[18]

Fechner's position in reference to predecessors and contemporaries is not very sharply defined. He was remotely a disciple of Schelling, learnt much from Baruch Spinoza, G.W. Leibniz, Johann Friedrich Herbart, Arthur Schopenhauer, and Christian Hermann Weisse, and decidedly rejected G.W.F. Hegel and the monadism of Rudolf Hermann Lotze.

Fechner DayEdit

It is claimed that, on the morning of 22 October 1850, Fechner awoke with a sudden new insight into how to study the mind. Moving away from Wundtarian introspection and basing his work on that of Weber, he developed his psychophysical Fechner scale. Each year, psychophysicists celebrate 22 October as the anniversary of Fechner's new insight as Fechner Day.[19] Celebrations to mark Fechner Day were organized by the International Society for Psychophysics and held in Fechner's home city of Leipzig in 2001.[citation needed]

Family and later lifeEdit

Little is known of Fechner's later years, nor of the circumstances, cause, and manner of his death.

Fechner was the brother of painter Eduard Clemens Fechner and of Clementine Wieck Fechner, who was the stepmother of Clara Wieck when Clementine became her father Friedrich Wieck's second wife.[citation needed]



  1. ^ [1]
  2. ^ Fancher, R. E. (1996). Pioneers of Psychology (3rd ed.). New York: W. W. Norton & Company. ISBN 0-393-96994-0. 
  3. ^ Sheynin, Oscar (2004), "Fechner as a statistician.", The British journal of mathematical and statistical psychology (published May 2004), 57 (Pt 1), pp. 53–72, PMID 15171801, doi:10.1348/000711004849196 
  4. ^ Michael Heidelberger (2004). "1: Life and Work". Nature from within: Gustav Theodor Fechner and his Psychophysical Worldview. University of Pittsburgh Press. p. 21. ISBN 9780822970774. The study of medicine also contributed to a loss of religious faith and to becoming atheist. 
  5. ^ Fechner, Gustav Theodor at
  6. ^ Schultz, P.D., & Schultz, S.E. (2008). A History of Modern Psychology.(pp. 81-82).Thompson Wadsworth.
  7. ^ Michael Heidelberger. "Gustav Theodor Fechner". / Retrieved 5 January 2014. 
  8. ^ Keynes, John Maynard; A Treatise on Probability (1921), Pt II Ch XVII §5 (p 201).
  9. ^ Fechner, G. (1876) Vorschule der Aesthetik. Leipzig: Breitkopf und Hartel. Website: chuoft.pdf
  10. ^ Campen, Cretien van (1996). De verwarring der zintuigen. Artistieke en psychologische experimenten met synesthesie. Psychologie & Maatschappij, vol. 20, nr. 1, pp. 10–26.
  11. ^ Galton F (1880). "Visualized Numerals". Nature. 21 (543): 494–5. doi:10.1038/021494e0. 
  12. ^ Galton F (1880). "Visualized Numerals". Nature. 21 (533): 252–6. doi:10.1038/021252a0. 
  13. ^ Galton F. (1883). Inquiries into Human Faculty and Its Development. Macmillan. Retrieved 2008-06-17. 
  14. ^ [Gazzinga, M.S (1970). The bisected brain. New York: Appleton-Century-Crofts]
  15. ^ Wallis, K.F. (2014). "The two-piece normal, binormal, or double Gaussian distribution: its origin and rediscoveries". Statistical Science, Vol. 29, No. 1, pp.106-112. DOI: 10.1214/13-STS417 [2]
  16. ^ Pojman, Paul, "Ernst Mach", The Stanford Encyclopedia of Philosophy (Winter 2011 Edition), Edward N. Zalta (ed.) [3]
  17. ^ Marshall, M E (1969), "Gustav Fechner, Dr. Mises, and the comparative anatomy of angels.", Journal of the history of the behavioral sciences (published Jan 1969), 5 (1), pp. 39–58, PMID 11610088, doi:10.1002/1520-6696(196901)5:1<39::AID-JHBS2300050105>3.0.CO;2-C 
  18. ^ For Hartshorne's appreciation of Fechner see his Aquinas to Whitehead – Seven Centuries of Metafysics of Religion. Hartshorne also comments that William James failed to do justice to the theological aspects of Fechner's work. Hartshorne saw also resemblances with the work of Fechner's contemporary Jules Lequier. See also: Hartshorne – Reese (ed.) Philosophers speak of God.
  19. ^ Kreuger, L. E. (1993) Personal Communication. ref History of Psychology 4th edition David Hothersal 2004 ISBN 9780072849653

Further readingEdit

  • Heidelberger, M. (2001), "Gustav Theodor Fechner" in Statisticians of the Centuries (ed. C. C. Heyde and E. Seneta) pp. 142–147. New York: Springer Verlag, 2001.
  • Heidelberger, M. (2004), Nature From Within: Gustav Theodor Fechner and his Psychophysical Worldview (trans. Cynthia Klohr), Pittsburgh, PA: University of Pittsburgh Press, 2004. ISBN 0-822-9421-00
  • Robinson, David K. (2010), "Gustav Fechner: 150 years of Elemente der Psychophysik", in History of Psychology, Vol 13(4), Nov 2010, pp. 409–410. [4]
  • Stigler, Stephen M. (1986), The History of Statistics: The Measurement of Uncertainty before 1900, Cambridge, MA: Harvard University Press, pp. 242–254.

External linksEdit