I'm referring strictly to SETI issues. I used to believe there were about a million civilizations in the Milky Way capable of either interstellar travel or communication using microwaves or lasers. This was based on my assignment of values to the Drake equation.

Now, I think we would be very lucky if there is even one other technical civilization in the Galaxy. In fact, it may be possible we are the first, and we may be the only one, that no others will arise to take our place.

We have solid evidence about how life arose and evolves, so we can make reasonable speculations about it. But we only have one example of a civilization capable of interstellar communication, our own. And it took four and a half billion years for our planet to generate us. And we have no way of knowing we aren't just a fluke.

That's what I mean by lonely. Having the Galaxy all to ourselves is a really terrifying thought for me.