Editing Mediocrity principle (section)

==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.