Topics Science

Question What is the correct resolution to the Fermi Paradox? As I understand it, the Fermi Paradox is physicist Enrico Fermi's acute observation of the discrepancy between the apparent high probability that extraterrestrial civilizations exist elsewhere in the universe, and the lack of empirical evidence of their supposed existence. It seems to me, that the Fermi Paradox is not a genuine paradox, as it neither commits self-reference nor leads to infinite regress. Any attempt to resolve this so-called paradox just needs to give an explanation for this discrepancy, but how does that contribute towards resolving the paradox? It seems that even if we were to make contact with an extraterrestrial civilization, the paradox would still be unresolved, so can there be any wholly satisfactory resolution to this paradox? Perhaps I just have the wrong attitude about it... I'm interested in seeing what other philosophers think about the Fermi Paradox, so that perhaps I may be assisted in developing my own stance on this issue.

Accepted:
April 29, 2010

Comments

I don't know what the precise definition of a "paradox" is, but roughly speaking, it is an argument that begins from premises that are too obvious to deny and ends by deriving from them a conclusion that is too ridiculous to accept. (Did Bertrand Russell say that somewhere?) By this standard, a paradox need not involve self-reference or lead to an infinite regress. Carl Hempel's famous "Paradox of Confirmation" (a.k.a. "Paradox of the Ravens") fits the above rough definition but involves neither self-reference nor infinite regress.

Now the Fermi Paradox, as you say, begins from several considerations that aim to show that it is highly likely that extraterrestrial civilizations exist. Perhaps none of these considerations is really too obvious to deny, but all of them are intended to be well-grounded (e.g., the number of potentially life-supporting planets in the universe). With a few further premises about interstellar communication, the conclusion of the argument is supposed to be that (it is highly likely that) we have been contacted by extraterrestrials. But that we have been so contacted is too ridiculous to accept (though when I was a kid, there was a cult book entitled "Chariots of the Gods" that purported to show that extraterrestrials had contacted us, helping the ancient Egyptians to build the pyramids and the like).

So we do have here a genuine paradox, under some generous definition of "paradox." The responses that have been given to this argument (e.g., that civilizations tend to last only a brief period of time, that interstellar communication is too costly, that extraterrestrial civilizations will tend not to try to communicate with one another) are too numerous and speculative for me to bother reviewing them. However, I disagree with your conclusion that if we were to make contact with an extraterrestrial civilization, then the paradox would not thereby be resolved. It would -- because the conclusion of the paradox (that we have been contacted by extraterrestrials) would then no longer be too ridiculous to accept.