
em 1950, ao contestar a idéia que poderiam existir inúmeras formas de vida alienígenas espalhadas pela galáxia.
citado em "Where are They? Maybe we are alone in the galaxy after all" by Ian Crawford in Scientific American (Julho de 2000), p. 38-43 (PDF document) http://www.cc.nctu.edu.tw/~tseng327/nctu-origin/article/sc200007a.pdf; veja também "Our Galaxy Should Be Teeming With Civilizations, But Where Are They?" by Seth Shostak at Space.com (25 de outubro de 2001) http://web.archive.org/web/20011107185016/http://www.space.com/searchforlife/shostak_paradox_011024.html