we are alone

From Discovery News:

Given the amount of time it has taken for human beings to evolve on Earth and the fact that the planet will no longer be habitable in a billion years or so when the sun brightens, Andrew Watson, with the United Kingdom's University of East Anglia in Norwich, says we are probably alone.

Earthlings overcame horrendous odds -- Watson pegs it at less than 0.01 percent over 4 billion years -- to achieve life. The harsh reality is that we don't have much time left.

This is basically modern support for the so-called "rare earth" theory, that says that intelligent life is an improbable abberation. If it's true, then SETI is a waste of time.

The problem is establishing the probability of an event after the event has actually occurred. While this is a knotty problem for statisticians, human brains are wired to perform such calculations quickly (but wrongly).
"We're here." goes the rule-of-thumb reasoning. "So how unlikely could it be for us to have evolved? Not very!"
However the fallacy of the reasoning can be seen if you look at the point of view of someone who has won the lottery. "It happened to me, so how unlikely can it be?"
Pretty unlikely.
The same might be true for the existence of intelligent life. We're cosmic lottery winners.