In the hunt for alien life, is man truly 'the measure of all things?'

Enrico Fermi's lunchtime question at wartime Los Alamos, "Where is everybody?" has been both a gift and a problem to scientists ever since. Known as "Fermi's Paradox," it simply asks, why, since life on Earth is ubiquitous and developed very early in Earth's history, and the galaxy is very old and not overly large, aren't there intelligent, advanced extraterrestrials everywhere? In particular, why can't we detect any, and why haven't any (obvious) aliens visited us?