[okie_tech]

The Occam's Razor conclusion would be that there are no other civilizations. Since there is no evidence of intelligent life. (including here on Earth ;-)

[headsonpikes]

"Since there is no evidence of intelligent life.(including here on Earth.;-)

Occam's Barber shop--two chairs, no waiting!

[discostu]

Nope, the Occam's Razor conclusion runs like this:
We have to go off of the evidence we have, assuming other species are significantly more or less advanced than ours is contrary to the available evidence.
Our detectable (communications) technology has only reached out to Alpha Cen (a little past but not to any other stars).
Our detection technology (again communications) is entirely hinged upon: A - when the other species developed the technology in relation to how far away from us they are (a civilization 4000 light years away won't be detectable until 4000 years AFTER they invent radio, and of course if their radio communications went past us (assuming they moved past that technology) before we invented the radio we're doubly SOL); and B - them using the same subsection of the carrier wave spectrum we do (that right there is highly improbable if based on random chance since we only use about 10% of the spectrum).
Therefore the simple solution is that our footprint is so small (only 1 other star) that nobody has noticed us, and that our "spotlight" we're aiming at the galaxy is so miniscule in detection width and penetration deapth that we're lucky we've managed to spot ourselves.