Editing Fermi paradox (section)

==== Extraterrestrial intelligence is rare or non-existent ====
It is possible that even if complex life is common, intelligence (and consequently civilizations) is not.<ref name="Lineweaver, 2009"/> While there are remote sensing techniques that could perhaps detect life-bearing planets without relying on the signs of technology,<ref>{{cite journal|title=Detecting Life-bearing Extrasolar Planets with Space Telescopes|bibcode=2008ApJ...684.1404B|author1=Steven V. W. Beckwith|doi=10.1086/590466|issue=2|journal=The Astrophysical Journal|volume=684|pages=1404–1415|date=2008|arxiv = 0710.1444|s2cid=15148438}}</ref><ref>{{cite journal|title=Detection of circular polarization in light scattered from photosynthetic microbes|author=Sparks, W.B. |author2=Hough, J. |author3=Germer, T.A. |author4=Chen, F. |author5=DasSarma, S. |author6=DasSarma, P. |author7=Robb, F.T. |author8=Manset, N. |author9=Kolokolova, L. |author10=Reid, N. |display-authors=etal|journal=Proceedings of the National Academy of Sciences|volume=106|issue=14–16|pages=1771–1779|date=2009|url=http://www.pnas.org/content/early/2009/04/28/0810215106.full.pdf |archive-url=https://web.archive.org/web/20150924175633/http://www.pnas.org/content/early/2009/04/28/0810215106.full.pdf |archive-date=2015-09-24 |url-status=live|doi=10.1016/j.jqsrt.2009.02.028|hdl=2299/5925 |hdl-access=free }}</ref> none of them have the ability to determine if any detected life is intelligent. This is sometimes referred to as the "algae vs. alumnae" problem.<ref name="Tarter-NYAS" />

Charles Lineweaver states that when considering any extreme trait in an animal, intermediate stages do not necessarily produce "inevitable" outcomes. For example, large brains are no more "inevitable", or convergent, than are the long noses of animals such as [[aardvark]]s and elephants. As he points out, "dolphins have had ~20{{nbsp}}million years to build a radio telescope and have not done so".<ref name="Lineweaver, 2009">[https://arxiv.org/abs/0711.1751 Paleontological Tests: Human Intelligence is Not a Convergent Feature of Evolution.] {{Webarchive|url=https://web.archive.org/web/20191220142600/https://arxiv.org/abs/0711.1751 |date=December 20, 2019 }}, Charles Lineweaver, Australian National University, Canberra, published in ''From Fossils to Astrobiology'', edited by J. Seckbach and M. Walsh, Springer, 2009.</ref> In addition, Rebecca Boyle points out that of all the species that have evolved in the history of life on the planet Earth, only one—human beings and only in the beginning stages—has ever become space-faring.<ref name="Rebecca Boyle, Quanta Magazine">[https://www.quantamagazine.org/galaxy-simulations-offer-a-new-solution-to-the-fermi-paradox-20190307/ "Galaxy Simulations Offer a New Solution to the Fermi Paradox"], Quanta Magazine "Abstraction Blog," Rebecca Boyle, March 7, 2019. "The sun has been around the center of the Milky Way 50 times," said Jonathan Carroll-Nellenback, astronomer at the University of Rochester.</ref>