Editing Fermi paradox (section)

==== Everyone is listening but no one is transmitting ====
Alien civilizations might be technically capable of contacting Earth, but could be only listening instead of transmitting.<ref name=webbwhere>{{cite book| last1=Webb| first1=Stephen| title=If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life| isbn=978-0-387-95501-8|url=https://books.google.com/books?id=Y111CQAAQBAJ&q=fermi+paradox+everybody+listening+nobody+sending&pg=PA148| access-date=June 21, 2015| date=2015| publisher=Springer}}</ref> If all or most civilizations act in the same way, the galaxy could be full of civilizations eager for contact, but everyone is listening and no one is transmitting. This is the so-called ''[[SETI]] Paradox''.<ref>{{cite arXiv |eprint=physics/0611283 |title=The SETI paradox |author=Alexander Zaitsev |date=2006}}</ref>

The only civilization known, humanity, does not [[Active SETI|explicitly transmit]], except for a few small efforts.<ref name=webbwhere /> Even these efforts, and certainly any attempt to expand them, are controversial.<ref>{{cite news |title=Should We Call the Cosmos Seeking ET? Or Is That Risky? |url=https://www.nytimes.com/aponline/2015/02/13/science/ap-us-sci-calling-the-cosmos.html |newspaper=The New York Times |author=The Associated Press |date=February 13, 2015 |access-date=March 1, 2017 |archive-url=https://web.archive.org/web/20150906144552/http://www.nytimes.com/aponline/2015/02/13/science/ap-us-sci-calling-the-cosmos.html |archive-date=September 6, 2015 |url-status=dead }}</ref> It is not even clear humanity would respond to a detected signal—the official policy within the SETI community<ref>{{cite web |url=http://www.seti.org/post-detection.html |title=Protocols for an ETI Signal Detection: Concerning Activities Following the Detection of Extraterrestrial Intelligence |publisher=SETI Institute |access-date=July 12, 2015 |archive-url=https://web.archive.org/web/20150718122415/http://www.seti.org/post-detection.html |archive-date=July 18, 2015 |url-status=dead }}</ref> is that "[no] response to a signal or other evidence of extraterrestrial intelligence should be sent until appropriate international consultations have taken place". However, given the possible impact of any reply,<ref>{{cite journal | last1 = Michaud | first1 = M. | title = Ten decisions that could shake the world | doi = 10.1016/S0265-9646(03)00019-5 | journal = Space Policy | volume = 19 | issue = 2 | pages = 131–950 | year = 2003 | bibcode = 2003SpPol..19..131M }}</ref> it may be very difficult to obtain any consensus on who would speak and what they would say.