Hawkings' enjoiner to avoid contact may be simply based upon his own peculiar vulnerability to your typical ravenous extraterrestrial horde. From a purely practical point of view, he's gonna have a tough time running away. (I am envisioning a marginally humourous moment from an imaginary invasionary science fiction horror film in which a Hawkings character might have a brief but satisfying cameo.) Not to be cruel, but colloquially, this is known as the "Spam in a Can" problem.
Dvorsky's counter has its own set of biases. The Fermi Paradox at base is contingent upon the puzzling assertion that no observable traces of extraterrestrial intelligence have ever been happened upn by humans. This flies directly in the face of literally thousands of incidents and encounters with completely unexplainable phenomena which have been documented in hundreds of books, official documents and eyewitness reports, to the extent that a variety of highly secretive and rather expensive divisions of ours and other governments and militaries have been devoted to this very issue. Fermi and presumably Dvosky, have never seen a UFO with their own eyes, so apparently evidence of any kind does not obtain. If you look closely enough at the question of UFOs, I believe the question is not "do they exist?" but "where are they from?" However, this perspective may not be as intrinsically cool as conjecturing a slew of objections and dismissals based upon projected mastery of nanotech or falling prey to the techno-singularity, a fate which I have to say, seems to be more something to avoid the more I understand about it.
According to the typical view of transhumanist thought, once the singularity occurs, the species essentially is transformed into a vestigal appendage of the godlike post-biological form which is then free to traverse time and space, wandering in an obsessive search for ever higher modes of computational processing. Boy, that sounds fun. Frankly, if enjoyment on the level of skipping down to the beach with your friends and your kids is beneath the awesome breadth of post-singularity civilisation, then the game's not worth the candle. The pleasures of the mundane must be highly underrated by Kurzweil, et al. Let's just hope that the be-all and end-all of existence doesn't shake down to how fast you can multiply figures in your head.
If exraterrestrial agents exist - and it seems they must - we have already surpassed a few of the milestones which would cause them to take notice of us. We have the ability to destroy our planet, and, if need be, probably the ability to destroy surrounding worlds, and we aren't really far from the ability to destructively affect our own sun, should we put our minds to it. But these aren't the attributes which bring value and substance to human life in the galaxy, rather that importance is likely predicated on our emotional depth. Don't forget how Kirk always overcomes the evil computers - with love.
I sort of figure that earth is located in a backwater area of the galactic disk outside of the usual lanes of interstellar traffic. You can't even see the galactic core form here, obscured as it is from view by huge clouds of opaque dust. I imagine that any real action to be had around here happens much nearer to the center of the galaxy where the stars coat the sky with such an impasto that the planetary evening must go by a different name, and where the giant and mysterious circumnuclear disk of Sagittarius A dominates the spacescapes with possibilites and intrigues. You can't keep 'em down on the farm once they've seen gay Paree.
