View source for Mediocrity principle

{{Short description|Philosophical concept}}
{{one source|date=December 2012}}

The '''mediocrity principle''' is the [[philosophical]] notion that "if an item is drawn at random from one of several sets or categories, it's more likely to come from the most numerous category than from any one of the less numerous categories".<ref name="Kukla2009">{{cite book |first=A. |last=Kukla |year=2009 |title=Extraterrestrials: A Philosophical Perspective |publisher=Lexington Books |isbn=9780739142455 |lccn=2009032272 |url=https://books.google.com/books?id=ZkdqTFVNwmgC&pg=PA20 |page=20}}</ref> The principle has been taken to suggest that there is nothing very unusual about the [[Formation and evolution of the Solar System|evolution of the Solar System]], [[Earth's history]], the [[evolution of biological complexity]], [[human evolution]], or any one [[nation]]. It is a [[heuristic]] in the vein of the [[Copernican principle]], and is sometimes used as a philosophical statement about the place of humanity. The idea is to assume mediocrity, rather than starting with the assumption that a phenomenon is special, privileged, exceptional, or even [[supremacism|superior]].<ref>{{Cite web|url=https://www.britannica.com/science/principle-of-mediocrity|title=astrobiology: principle of mediocrity |website=Britannica}}</ref><ref name=MediocrePZ>{{cite web|url=http://www.edge.org/q2011/q11_12.html#myerspz|title=THE WORLD QUESTION CENTER 2011 — Page 12|access-date=2011-04-25|archive-url=https://web.archive.org/web/20170617103245/https://www.edge.org/q2011/q11_12.html#myerspz|archive-date=2017-06-17|url-status=dead}}</ref>

[[David Bates (physicist)|David Bates]] ascribed the mediocrity principle to [[Sebastian von Hoerner]],<ref>{{Cite magazine |last=Bates |first=D. R. |date=1972 |title=Communication with galactic civilizations |url=https://iopscience.iop.org/article/10.1088/0031-9112/23/1/013 |magazine=Physics Bulletin |volume=23 |issue=1 |pages=26–29 |doi=10.1088/0031-9112/23/1/013 |issn=0031-9112}}</ref><ref>{{Cite book |last=von Hoerner |first=Sebastian |title=Interstellar Communication: The Search for Extraterrestrial Life; A Collection of Reprints and Original Contributions |publisher=Benjamin |year=1963 |editor-last=Cameron |editor-first=A. G. W. |location=New York |pages=272}}</ref> who as early as 1961 wrote the following:<ref>{{Cite magazine |last=Von Hoerner |first=Sebastian |date=1961 |title=The Search for Signals from Other Civilizations |url=https://www.jstor.org/stable/1707703 |magazine=Science |volume=134 |issue=3493 |pages=1839–1843 |jstor=1707703 |issn=0036-8075}}</ref><ref group=notes>In a footnote, von Hoerner thanked [[Frank Donald Drake|F. D. Drake]] for his input on the subject.</ref>
{{quote|
Because we have no knowledge whatsoever about other civilizations, we have to rely completely on assumptions. The one basic assumption we want to make can be formulated in a general way:

::: Anything seemingly unique and peculiar to us is actually one out of many and is probably average.
}}

==Extraterrestrial life==
The mediocrity principle suggests, given the existence of life on Earth, that should [[life]] exist elsewhere in the [[universe]], it will typically exist on [[Earth analog|Earth-like planet]]s.<ref>{{cite book|last1=Chaisson|first1=Eric|first2=Steve|last2=McMillan|title=Astronomy: A Beginner's Guide to the Universe|edition=6th|location=San Francisco|publisher=Pearson|year=2010|isbn=9780321605108}}{{page needed|date=August 2012}}</ref>

== Measurement of distance to stars ==
The mediocrity principle was implicitly applied during the 17th century, when astronomers attempted to measure the distance between distant [[star]]s and the [[Earth]]. By assuming that the [[Sun]] was just an average star, and that some stars seemed brighter simply because they were closer to us, they were able to estimate how far these stars were from the Earth. Although this method was flawed due to the differences among stars, it gave astronomers at that time a rough idea of how far the stars were from the Earth. For example, [[James Gregory (mathematician)|James Gregory]], [[Isaac Newton]] and [[Christiaan Huygens]] were able to estimate the distance between [[Sirius]] and the Earth through this method.<ref>{{cite book |last1=Gingerich |first1=Owen |title=God's Universe |url=https://archive.org/details/godsuniverseowen00ging |url-access=registration |date=2006 |publisher=The Belknap Press of Harvard University Press |location=Cambridge, Massachusetts |page=[https://archive.org/details/godsuniverseowen00ging/page/20 20]|isbn=9780674023703 }}</ref>

==Comparison with other approaches==
The mediocrity principle is in contrast with the [[anthropic principle]], which asserts that the presence of an intelligent observer (humans) limits the circumstances to bounds under which intelligent life can be observed to exist, no matter [[Rare Earth hypothesis|how improbable]].<ref>{{Cite web|url=http://abyss.uoregon.edu/~js/cosmo/lectures/lec24.html|title=Anthropic Principle|website=abyss.uoregon.edu}}</ref> Both stand in contrast to the [[Fine-tuned universe|fine-tuning hypothesis]], which asserts that the natural conditions for intelligent life are implausibly rare.

The mediocrity principle implies that Earth-like environments are necessarily common, based in part on the evidence of [[Doomsday argument|any happening at all]], whereas the anthropic principle suggests that no assertion can be made about the probability of intelligent life based on a sample set of one ([[Dunning–Kruger effect|self-described]]) example, who are necessarily capable of making such an assertion about themselves.

It is also possible to handle the Mediocrity Principle as a statistical problem, a case of a single [[data point]] statistics, also present in the [[German tank problem]].

==Longevity estimation==
{{See|Lindy effect}}
{{Image frame
|align=right
|content=<math>\begin{array}{c}
\left(\frac{z}{1 - z}\right) \cdot T_{\text{start}} \le T_{\text{now}} \le \left(\frac{1 - z}{z}\right) \cdot T_{\text{end}} \\
z = \frac{1 - \text{confidence interval}}{2}
\end{array}</math>
|caption=Longevity Estimation Equations
}}

The mediocrity principle can also be used to estimate the future [[life expectancy]] of presently observable objects, and is especially useful when no hard [[data]] is available. [[J. Richard Gott|Richard Gott]] extended the mediocrity principle to argue that if there is nothing special about observing an object in the present moment (T<sub>now</sub>), then one can expect the present moment to occur randomly between the start (T<sub>start</sub>) and the end (T<sub>end</sub>) of the observed object's longevity. Therefore, the total longevity of an observable object can be expected (with 50% confidence) to lie in the [[Interval (mathematics)|interval]] 1/3 ⋅ T<sub>start</sub> < T<sub>now</sub> < 3 ⋅ T<sub>end</sub>. This estimation technique was derived after a 1969 visit to the [[Berlin Wall]], which was constructed eight years earlier. Gott reasoned that there was nothing special about the timing of his visit, so the above equation (with T = 8) estimates that the Berlin Wall would be likely to last for at least 2.67 years but no longer than 24 years. (The Berlin Wall fell 20 years later, in 1989.) 

[[File:Estimation.png|thumb|Time interval of a random observation within a lifespan]]

Longevity estimation reflects the [[Maxim (philosophy)|maxim]] "old things tend to last and new things tend to disappear." Most applications of longevity estimation use a 95% confidence interval, which decreases the precision of the estimate by drastically increasing the interval of estimation. One useful estimation made on this confidence interval is the survival of [[Human|Homo sapiens]], which is thought to have emerged around 200,000 years ago. If there is nothing special about our observation of [[species]] now, in the 21st century, then longevity estimation (with T = 200,000 and a confidence interval of 95%) yields a projected timespan of between 5,100 and 7.8 million years during which the human species will be extant. 

Some other projected lifespans (with 95% confidence) include [[industrial technology]] (estimated to last somewhere between 7 years and 10,000 years), the [[internet]] (between 7 months and 975 years), and [[Wikipedia]] (between 6 months and 772 years). [[Jim Holt (philosopher)|Jim Holt]] analyzed longevity estimation and concluded that our understanding of [[Humour|humor]] and [[number]] will survive for at least one million years. Humans share these traits with other species, which implies we share these traits with some [[Most recent common ancestor|common ancestor]] that lived millions of years ago.

==Other uses==
[[David Deutsch]] argues that the mediocrity principle is incorrect from a physical point of view, in reference either to humanity's part of the universe or to its species. Deutsch refers to [[Stephen Hawking]]'s quote: "The human race is just a chemical scum on a moderate-sized planet, orbiting around a very average star in the outer suburb of one among a hundred [[billion]] galaxies". Deutsch wrote that Earth's neighborhood in the universe is not typical (80% of the universe's matter is [[dark matter]]) and that a concentration of mass such as the Solar System is an "isolated, uncommon phenomenon". He also disagrees with [[Richard Dawkins]], who considers that humans, because of natural evolution, are limited to the capabilities of their species. Deutsch responds that even though evolution did not give humans the ability to detect [[neutrino]]s, scientists can currently detect them, which significantly expands their capabilities beyond what is available as a result of evolution.<ref>{{cite book |isbn=978-0-14-196969-5 |title=The Beginning of Infinity |author=David Deutsch|year=2011|publisher=Penguin UK |author-link=David Deutsch }}</ref>{{clarify|date=August 2015}}

==See also==
{{div col|colwidth=15em}}
* [[Abiogenesis]]
* [[Anthropic principle]]
* [[Copernican principle]]
* [[Cosmicism]] 
* [[Cosmological principle]]
* [[Cosmic pluralism]]
* [[Deep ecology]] 
* [[Doomsday argument]]
* [[Drake equation]]
* [[Exceptionalism]]
* [[Neocatastrophism]]
* [[Particle chauvinism]]
* [[Plenitude principle]]
* [[Rare Earth hypothesis]] 
* [[Uniformitarianism]]
{{div col end}}

==Notes==
{{Reflist|group=notes}}

==References==
{{Library resources box}}
{{Reflist|refs=
* Gonzalez, Richards, ''The Privileged Planet: How Our Place in the Cosmos is Designed for Discovery'', Regnery Publishing, [[2004 in literature|2004]], {{ISBN|0-89526-065-4}}
* [[Peter Ward (paleontologist)|Peter Ward]] and [[Donald E. Brownlee|Donald Brownlee]], ''[[Rare Earth: Why Complex Life is Uncommon in the Universe]]'', Copernicus Books, January [[2000 in literature|2000]], {{ISBN|0-387-98701-0}}
* [[Richard Gott|J. Richard Gott III]], ''Implications of the Copernican principle for our future prospects'', Nature. 363: 315-319. May 1993
* [[Jim Holt (philosopher)|Jim Holt]], ''[[When Einstein Walked with Gödel|When Einstein Walked with Gödel: Excursions to the Edge of Thought]]'', Farrar, Straus and Giroux, May [[2015 in literature|2015]], {{ISBN|978-0374146702}}
}}

== External links ==
{{Wiktionary|mediocrity}}
* [https://arxiv.org/abs/astro-ph/9704289v1 Goodwin, Gribbin, and Hendry's 1997 Hubble Parameter measurement relying on the mediocrity principle] The authors call this the 'Principle of Terrestrial Mediocrity' even though the assumption they make is that the Milky Way ''Galaxy'' is typical (rather than Earth). This term was coined by [[Alexander Vilenkin]] (1995).

{{Extraterrestrial life}}

{{DEFAULTSORT:Mediocrity Principle}}
[[Category:Earth]]
[[Category:Philosophy of science]]
[[Category:Principles]]
[[Category:Search for extraterrestrial intelligence]]