Abstract :
Some critics of the Search for Extra-Terrestrial Intelligence (SETI) like to bolster their arguments with what they call the Fermi Paradox. Legend has it that one day at Los Alamos, shortly after the Alamogordo test (when the first atomic bomb was exploded in the desert about 50 miles northwest of this town on July 16, 1945), Enrico Fermi abruptly broke the meal-time silence with the question: where are they? Meaning, of course, that since advanced extra-terrestrials presumably have long had nuclear power, why haven´t we been visited? Today this so-called paradox-really a syllogism in fuzzy probabilities, is stated this way:(a) interstellar travel is easy, at least for advanced extraterrestrial intelligence (ETI); (b) if the Galaxy is rife with ETI, at least one civilization would have colonized it by now; (c) we see no evidence of this. Therefore, say these impeccable logicians, ETI must be rare or, even better, perhaps we are the only intelligent life after all. There are of course many other explanations for our absence of evidence.<>
Keywords :
extraterrestrial life; fuzzy logic; probabilistic logic; Fermi Paradox; Galaxy; SETI; Search for Extra-Terrestrial Intelligence; advanced extra-terrestrials; civilization; extraterrestrial intelligence; fuzzy probabilities; interstellar travel; Cities and towns; Costs; Geoscience; Humans; Logic; Mars; Moon; Nuclear weapons; Rockets; Testing;