…largely seem to me to be evidence of the human tendency to fill silence and empty space with something, whether or not there is any evidence for it.
This is true, not only of the average post-modern who routinely assumes the existence of ET, but also of people like this, who magisterially declare that We Are Alone.
The truth is that the only thing we know is that We Don’t Know Anything. We have no evidence either way and the people who declare we are alone are talking through their hats as much as those who declare the universe to be teeming with life based on the Drake Equation. The Drake Equation is an impressive looking formula full of variables that look really cool and mean absolutely nothing since we have no idea what the value of any of them is. Similarly, the big problem for the We are Alone crowd is that they, you know, don’t know if We Are Alone. We don’t know nuthin’. We are ignorant. But we insist on making confident pronouncements rather than just saying, “Who knows? Maybe there’s someone there, maybe there isn’t. How about we focus on the data and see what we see?”
The fun thing is that we are starting to acquire data as we find more and more planets around other stars. The hope is that a spectal analysis of the light from those planets might reveal the presence of chlorophyll. Likewise, probes to Io will be looking for the possibility of life around black smoker vents at the bottom of the ocean under the ice. But till we look we won’t know. And even if we find nothing, that doesn’t mean there’s no extraterrestrial life. It will just mean we eliminated a little of our ignorance.
That’s not to say we will ever contact non-human intelligences from other planets. My money is against it, even if they are there. We’ve been listening for 50 years and the heavens are remarkably silent for a galaxy allegedly teaming with other civilizations. Still less are we ever going to get off this rock in any significant way. We might set up a colony on the Moon for some reason and we might terraform Mars. But since it would be vastly easier and cheap to build New York in Antarctica (where you don’t have to import an atmosphere) than to build even a modest colony off world, and since the nearest star is really, really, really far away, I just don’t think it’s happening. The only non-human intelligences we will ever encounter are the ones that have been here all along: angels and demons. The dream of the Conquest of Space and our imminent contact with ET is basically just Christian eschatology transposed into a secular mythos.