It is often suggested that extraterrestial life sufficiently advanced to be capable of interstellar travel or communication must be rare, since otherwise we would have seen evidence of it by now. This in turn is sometimes taken as indirect evidence for the improbability of life evolving at all in our universe. A couple of other possibilities seem worth considering. One is that life capable of evidencing itself on interstellar scales has evolved in many places but that evolutionary selection, acting on a cosmic scale, tends to extinguish species which conspicuously advertise themselves and their habitats. The other is that—whatever the true situation—intelligent species might reasonably worry about the possible dangers of self-advertisement and hence incline towards discretion. These possibilities are discussed here, and some counter-arguments and complicating factors are also considered.
The Fermi paradox is an interesting enough subject for our purposes that I think it deserves the exposure, and I think Motl’s opinion is probably close to the truth, but I’m still not really happy with this treatment of it.
The style of argument Motl employs seems to be based mainly on ridicule: he rarely seems to go much past stating a claim in such a way as to seem improbable on its face and pointing out that superficial improbability. That’s absolutely not a style I want to become normalized around here, dealing as frequently as we do with topics that seem outlandish or counterintuitive, and I didn’t find the content very enlightening.
Too Damned Quiet?, arXiv.org—Submitted on 4 Apr 2011
A Harvard string theorist disagrees
The Fermi paradox is an interesting enough subject for our purposes that I think it deserves the exposure, and I think Motl’s opinion is probably close to the truth, but I’m still not really happy with this treatment of it.
The style of argument Motl employs seems to be based mainly on ridicule: he rarely seems to go much past stating a claim in such a way as to seem improbable on its face and pointing out that superficial improbability. That’s absolutely not a style I want to become normalized around here, dealing as frequently as we do with topics that seem outlandish or counterintuitive, and I didn’t find the content very enlightening.