“Humans will not find features of an exoplanet or other object >1 light-year away which, according to a majority of astrobiologists, is convincing evidence of life, intelligence, or technology; nor will we detect any other electromagnetic signal satisfying the same requirement.”

Twenty years from now, we will have searched many millions of exoplanets, only to find the same bland, racemic mixtures of simple compounds everywhere. The carbon/nucleotide-based life found on Earth (and possibly other planets/satellites in our Solar System) is the only such complex or directed chemistry in the observable universe. Aliens — specifically, any similarly continuous lineage of complex chemistry (broadly defined) that gathers, stores, and uses information, but is disconnected from our continuous lineage — dwell in their own universes, unobservable from ours. I believe that the experiments of quantum mechanics inevitably lead to this conclusion, and this is the resolution of the so-called Fermi paradox. The full argument is laid out at http://simplestcasescenario.com (free to read).