In a message dated 09/10/1999 4:33:15 PM Eastern Daylight Time, firstname.lastname@example.org writes:
> Yes, absence of aliens may indicate that intelligent life eventually
> destroys itself and its environment. EOM
I am betting that Technology -Building life is extremely rare. Not because they decide to polute or to huff nukes or to nano-crap on themselves. I am suspecting that the initial conditions that promote tool users are vanishingly rare. Items such as Yellow stable stars, a local sizable moon, a huge gas giant to slurp up the comets and asteroids, convection and subduction between an early planets surface and its mantle, the right climate..etc. Also I contend, that 12-20 billion years is a subjective view on what it takes to bring forth intense self awareness. We may be the first beings in the Local Group to attain this awareness. We are set ( I suspect) against the after-glow of creation. Flip a coin.