A few pieces of evidence regarding aliens:
- UFO sightings have been regularly reported and carefully recorded for decades.
- Similarly for crop circles.
- Similarly for abduction experiences.
- There are ancient artifacts could not have been constructed by the humans of the time. Who made them?
- The Mexican government has admitted the existence of aliens, and former US government officials have claimed that the US government knows that aliens exist and is not telling anybody.
Of the first four items, each represents a large area of research, with numerous data points and theories. In each case, some of the data points have been debunked; some of them appear very difficult to debunk, with a variety of skeptical explanations definitively ruled out; and the vast majority are ambiguous.
Is there any piece of evidence that “puts the nail in the coffin” regarding aliens? Well, aliens have never landed in the middle of Times Square on a Monday afternoon.
But what does it take to really nail down a proposition? Presumably none of these individual data points are enough by themselves to nail down aliens. But there are millions of them. You can’t say that they’re all hoaxes. Well, you can, but at that point a certain razor needs to step in.
So I ask again, what does it take to really nail down a proposition? What standard of proof do we require? A lot of ideas are widely accepted and credible, on far less evidence than what we here have on offer. Academics accept the DSM, set theory, Martin Heidegger, and so forth, on far less evidence than what we have put forth here.
Infallible proof is talked about more often than it is actually obtained. Compared to the number of ideas that have been floated since the inception of knowledge, the number of ideas that have been truly “nailed down” is miniscule. (It seems like a larger proportion of the total ideas because we keep on teaching those same few ideas over and over to every person who goes through school.) And even those few ideas aren’t nailed down in an absolute sense.
I would put aliens in an epistemic position similar to that of dark matter. We can’t see dark matter, or aliens. But we can deduce, detective-style, that it’s hard to explain how the universe holds together without dark matter, or aliens. Note, not “impossible to explain,” but “hard to explain.” Which in the case of dark matter, is enough to make us believe.
Why do we feel differently about aliens? I think it’s not because the evidence isn’t good enough. It’s not a lack of evidence that makes us reluctant; it’s something else. What?
- The issue is important. If aliens are actually interacting with humans behind the curtains, that has huge implications for the future of humanity and our place in the universe. The more important something is, the more evidence we demand.
- Though there is no lack of evidence, all of the evidence is ambiguous. In some ways, a huge mass of ambiguous evidence is less convincing than a small amount of unambiguous evidence. Statistically speaking, a large amount of ambiguous evidence is probably no less weighty than a small amount of unambiguous evidence; but it’s less cognitively accessible.
- The idea is completely divergent from how we understand the world. Forget quantum physics; forget black holes and dark matter; forget evolving from apes; this is weird. A lot of people feel like aliens are somehow inconsistent with science. They aren’t; they don’t challenge materialism, reductionism, empiricism, or anything else. But there’s still this unshakeable feeling of, this is inconsistent with reality as I understand it. And it is.
 The “ancient aliens” argument has been criticized on the grounds that it is fallacious to infer from an unexplained phenomenon (artifacts that humans of the time could not have built) to the explanation of aliens. But it’s not so fallacious. We can safely say that things like statues and artistic landforms are made by sentient beings. If humans didn’t do it, some other sentient beings did. We know of no appropriate sentient beings, besides humans, that exist on Earth. If they’re not from Earth, they’re from somewhere else.