^ This.
Well put
Correa Neto. To that I would add a considerable body of knowledge (read Science) exists establishing that eyewitness “testimony” is notoriously unreliable and this must be taken into account when evaluating UFO reports.
No one is immune to this, not even myself I must admit. Given that historically (ref. USAF Project Blue Book) some 95% of UFO reports ultimately turn out to be identifiable, this is very strong (statistical?) evidence that there are perhaps some confounding observational errors present in the accounts of the remaining 5% or so that prevent conclusive identification, if not other contributing factors.
As far as I know the (granted, fairly loosely defined and informal) PSH (as opposed the ETH and others) is the only hypothesis that has yet to be falsified…
Psychosocial hypothesis
http://en.wikipedia.org/wiki/Psychosocial_hypothesis
If the aim of UFOlogy is to prove that aliens are in our midst and not just sell books and other promotional materials to the benefit of it’s practitioners or become another religion, they’re going to have to produce some scientifically verifiable (objective) evidence.
As it turns out, this can be accomplished (that is of course assuming alien spaceships are actually flying around in our atmosphere) with a very modest investment in some instrumentation… in fact for about the same amount it costs to fly a bunch of “credible” witnesses to Washington DC for a press conference.
One wonders why UFOlogists invariably choose the latter as opposed to the former approach?