Page "Drake equation" Paragraph 3

The Drake equation is closely related to the Fermi paradox in that Drake suggested that a large number of extraterrestrial civilizations would form, but that the lack of evidence of such civilizations ( the Fermi paradox ) suggests that technological civilizations tend to disappear rather quickly.

This leads to the Great Filter, which notes that since there are no observed extraterrestrial civilizations, despite the vast number of stars, then some step in the process must be acting as a filter to reduce the final value.

According to this view, either it is very hard for intelligent life to arise, or the lifetime of such civilizations must be relatively short.