If intelligent life exists elsewhere in the universe, where is everyone? Enrico Fermi’s 1950 question has elicited many theories in the sixty years since. If advanced life was as commonplace as Frank Drake or Carl Sagan believed, it seems unlikely that not a single extraterrestrial civilization would have made itself known to us.
Some, like futurist Ray Kurzweil, believe that this means that we are alone in the universe: the product of a series of astronomically unlikely occurrences. Kurzweil reasons that any advanced civilization would use all the matter of its own planet for computing, then radiate outward from their home world. The fact that no one seems to have done this already is supposedly evidence that we are alone.
I think this is a remarkably anthropocentric view of the universe. Both Fermi’s Paradox and Kurzweil’s reasoning employ the same faulty assumption that extraterrestrial life would act the same way that humans might. How can we possibly guess the goals of an extraterrestrial civilization when we don’t even know how our own civilization will act in the future? Why should we assume that extraterrestrials will be expansionists, desiring to conquer (or even communicate with) the rest of the universe? This is a remarkably human trait to project onto other potential civilizations. It’s entirely possible that extraterrestrial life does exist, but is simply not interested in interacting with us, content with not venturing far from their home worlds. Any civilization capable of interstellar travel or communication will almost certainly have access to anything it wants at home, and perhaps would have no particular reason to be interested in a pale blue dot populated by bipedal apes.
There is another, darker explanation for the lack of contact with extraterrestrials. If advanced civilizations tend to eliminate any inferior civilizations with which they come in contact, then we will have no evidence of them until immediately before our extinction, if at all. The fact that we have not yet been eliminated, then, simply means that no other advanced civilizations are aware of our presence yet. We can employ the Anthropic Principle here: We would not be here to speculate about Fermi’s Paradox if we had been discovered by another civilization.
These are the explanations for Fermi’s Paradox which seem the most plausible to me. The least plausible explanation is the one Kurzweil suggests: That we are alone. Even if advanced life developed in only one in a billion solar systems, there would be trillions of civilizations in the vastness of our universe. Finding them, however, may be much more difficult. Perhaps a truly intelligent civilization would leave no evidence of its existence at all.