This may be a tad long for some people, but I think it’s worth it. Neil DeGrasse Tyson patiently explaining many of the reasons the so-called evidence for UFOs is rejected. It also couples nicely with why you should think like a scientist over at Uncertain Principles, because the UFO crowd could use a good dose.

Specifically,

Stripped to its essentials, science is a four-step process: you look at something interesting in the world, you think about why it might work that way, you test your idea with further observations and experiments, and you tell everybody you know what you found.

Any group falling into the argument-from-ignorance pit that Tyson describes are skimping on step 2, when they leap to the conclusion that, e.g. what they saw is an alien, rather than thoroughly thinking about/investigating other possibilities, and then they completely omit step 3, proceeding straight to 4. (5, of course, is right out)

Tyson gives one example of step 3 — grabbing some physical object if you’re ever abducted. There are other possibilities, but they have to better than blurry pictures or videos. There’s really no excuse, either, because there are plenty of amateur/citizen scientists out there, doing quality, rigorous work. The UFO crowd refuses to live up to that standard, and they will continue to be marginalized as a result. (They’ll be marginalized if/when they come up empty-handed, of course, but that shouldn’t stop someone who is convinced they will find the crucial evidence)