Originally Posted by JayUtah

I see a big difference between people like NGCHunter and his family, and people like Billy Meier whom I'd classify as the visitees I think Hawking is talking about.

If you see something in the air, and it looks like a vehicle to you, and you report that honestly, I don't see anything cranky about that. You can even speculate that it may be a vehicle of unknown and possibly fantastic origin, and that doesn't really make you cranky. Speculation itself doesn't necessarily have to blur the disctinction between observation and interpretation. That is, one can rationally do both as long as one recognizes the difference.

But Billy Meier, on the other hand, can't hide behind ambiguity. He claimed to be visited regularly by entities who made it absolutely clear that they were not of this Earth. That is a tall claim. He leaves us only two choices: that space aliens do indeed exist unmistakably, or that Meier is a liar. It's the ultimate UFO throw-down.

But with a less deterministic sighting we can admit that it may not be something ordinary, or ordinarily perceived, without necessarily having to also draw the conclusion that space aliens exist. The inability to explain it by prosaic means does not lead inexorably to the space-alien conclusion, and not all witnesses attempt to draw that conclusion. That's how I can say that Billy Meier is a crank and NGCHunter's family are not.

UFO sightings do not prove alien life exists. But Meier's experiences, if they had been true, would have proven it. So in Hawking's larger context of how to know whether there is alien life in the galaxy, I draw the distinction between what would work as proof and what wouldn't, assuming for the sake of argument that all the observations were true. "I saw something fantastic in the sky," is not proof of aliens. "Alien beings visited me," is.