ProphetofOccam
Paranormal Adept
Saying something is unknowable because humanity has been bashing it's head into the same brick wall for 60 years is like saying we'll never know what the dark side of the moon looks like because humanity hasn't seen it for all of recorded history.
I don't really agree with that. Can you name another field in which we've made zero headway in understanding the nature, cause, or predictability of a phenomenon? Even with constructs of deep space, most of the math and deduction is based on observable, measurable factors.
Someone said, "hey, we observe this phenomenon, what might be going on?" A few folks use numbers and other knowns to create a (or several) hypothesis. Then, work is put into using the knowns to design tools or procedures for observing the unknown factor associated with the original observation. For instance, we can now detect the presence of blackholes, where they had previously just been an idea based on physical and objective observation, as we've developed tools and procedures for doing that based on those observations, built around a hypothesis.
With UFO's, no honest hypothesis is possible, as of yet, as we don't really have anything to observe with any level of reliability or predictability. Even if we did, we have no way of knowing if one UFO we see in the night is an identical phenomenon to another. We can make assertions, but what would they be based on? "Ok, so this particular UFO isn't behaving like the other UFO I also didn't know anything about, so I have decided that it is a different phenomenon." In science, and general objective thinking, that's not Kosher.
We may one day have a UFO to observe (be it a spaceship, a plasma ball, or some kind of interstellar whale), but as of now there isn't even the slightest inkling of how to gather that type of necessary data, generate evidence, or even make reliable, confirmable observations. In that way, UFO's might as well be a deity. People are just asserting about factors for which we don't have any objective information. It's fun, sure, but it doesn't have a great deal of value beyond that.
I assert that it is probably unknowable, because it's the only field in which people have made no advancement. Advancement is impossible without objectivity and specific corroboration. UFOlogy uses semantics and philosophical notions to dance around that fact, but nobody who might be able to provide answers is really interested in word games -- they're interested in results.