And when we talk about things that hardcore UFO skeptics won't believe, we begin to hit emotional paydirt. There's every sign that, with them, denial is running rampant. Before going further, let me say (a) that just because skeptics may be in some kind of denial doesn't prove that UFOs are alien, and (b) that it doesn't even prove all skeptics are fools. In fact, we need skeptics. We shouldn't believe that aliens are here unless they really are, and until we're sure, it's helpful to have people acting as defense attorneys, giving all the arguments against.
   But it's hard to read much skeptical UFO literature without concluding that the most prominent skeptics can be zany, not to say wildly out to lunch. Take Carl Sagan, for example, the scientist (and longtime PBS talking head) who sued Apple Computer when the company code named a project "Butthead Astronomer " (Originally they'd called it "Sagan," and changed the name when Sagan objected. He lost the lawsuit, by the way.)
   In his 1973 book The Cosmic Connection, he tells us not just why UFOs aren't visiting, but why they couldn't be. His argument goes more or less like this. Let's suppose, he says, that people see just one genuinely extraterrestrial UFO each year. Actually, of course, there are many more provocative UFO reports than that, but Sagan makes his conservative assumption for a very sly reason. If even one visit is unlikely, he wants to show us, then the number of UFOs actually reported is nothing short of ridiculous.
   And why would even one annual visit be unlikely? Well, you've got to do a little math. You start with the number of technically advanced civilizations there might be in the galaxy. You imagine that they might be sending probes to check out other planets, and you estimate the number of places they might want these probes to visit. Now you do some calculations. How many spaceships would have to be wandering through space before it's likely that one of them would stumble on us once each year?
   The answer turns out to be staggering. Each civilization, Sagan says, would have to launch ten thousand ships each year before we'd have our visitors!
   Case closed, except that it might have struck some readers, just for a start, that the numbers Sagan plays with are pretty arbitrary. Nobody knows how many civilizations there are in the galaxy; all Sagan can do is guess.
   Furthermore, why should we assume as Sagan does, that each solar system has an equally random chance of being visited? Presumably, these magnificent spacefaring races start by looking at the planets nearest to them. If we're in a populated part of the galaxy, we might be visited pretty often.
   But what really kills the argument is another assumption, one so absurd that, quite frankly, it's laughable. Why does each sighting have to represent a fresh interstellar visit? Why couldn't people see the same craft more than once?
   Or, for that matter, why couldn't aliens borrow a scenario from Independence Day (just as the writers of the film borrowed it from countless predecessors), and arrive in one huge ship, which then disgorges an armada of smaller scouts? Voila - hundreds, maybe thousands of UFOs to spot.
   Once you allow for these elementary possibilities, Sagan's argument evaporates. And since the whole thing proves to be nothing more than smoke and mirrors, it's fair to ask why someone so obviously smart would think so stupidly. The most likely answer, I think, is that Sagan wants to believe that UFOs aren't here. You could say he's like those early UFO researchers, who didn't want to believe that UFOs might land. Though Sagan moves the goal posts even further back, by making up reasons not to believe in UFOs at all.

And if you think that's bad, look at Donald Menzel, a Harvard astronomer, now dead, who was the leading UFO skeptic of the '50s and '60s. Menzel, who never saw a UFO case he thought was even mildly plausible, tried to "solve" the 1958 sighting of an Anglican priest, Father Gill. Gill, working as a missionary in New Guinea, said he'd seen a craft hover overhead for many minutes, with beings on board who waved at him. His New Guinean parishioners corroborated his account.
   How did Menzel drive the UFO away? Here, in all its wacky glory, is his analysis, published not in Mad magazine, where it probably belonged, but in a scientific book (UFOs: A Scientific Debate, edited by Carl Sagan and Thornton Page):

Suppose that the priest, perhaps unknown to himself, has considerable myopia and astigmatism in his eyes. I decided that I could simulate both the myopia and astigmatism with the aid of lenses. From a large selection of spectacle lenses, which I occasionally use in my astronomical experiments, I chose a positive lens that had a certain amount of astigmatism. I removed my spectacles and inserted this lens in one eye, something like a monocle. To my delight, but not to my surprise, Venus and the other stars flattened out and became saucers. But the remarkable thing was an appearance caused by the slightly out-of-focus images of my eyelashes. With a little imagination, these luminous projections, extending above and below the saucer-shaped image, appeared like the men or legs of Father Gill's drawing. The slight movement of my eye, up or down, caused the "men" to move around. The slight irregularities on the hairs of the lashes, perhaps dust or moisture, could easily be interpreted as activity of the "beings" inhabiting the saucer.

So Father Gill stood there for half an hour, watching his eyelashes? Someone who'd imagine such a thing must be wildly anxious to keep UFOs at bay. And Menzel's theory seems even loonier once you know that he made no attempt to check it; he didn't, for example, bother to ask whether Father Gill was astigmatic, or even if he wore glasses of any kind.
   To his credit, Menzel admitted, more or less, that he wasn't exactly on solid ground here; he labeled his analysis mere speculation. But he went on to insist his explanation was "a reasonable one, and much more probable than the alternative, that UFO's were flying over Papua, trying to communicate with the inhabitants."

Now that's a fascinating notion. How, exactly, does Menzel know how unlikely an alien visit to New Guinea or anywhere else might be? This brings us to the centerpiece of UFO denial. In Menzel's time, and also in ours, most top-rank scientists have agreed that UFO visits aren't very probable.
   How do they know that? Well, we've seen Sagan's argument. But most scientists don't need to get that fancy. They're simply convinced that interstellar distances are too vast for anyone to cross. The people most involved in making that argument are, interestingly enough, the ones most concerned with finding alien life. These are the scientists involved in SETI, the "search for extraterrestrial intelligence."
   They're very serious about the quest; they've devoted endless hours (and millions of dollars, in federal and other funding) to an ongoing search for alien radio signals. None have been found, which of course doesn't mean that the quest is useless.
   What's fascinating, though, is the reasoning behind the plan. Frank Drake, an astronomer who's a leader of the SETI adventure, lays it out quite clearly in a book he wrote with a former New York Times science reporter, Dava Sobel, called Is Anyone Out There? He paints a majestic picture of a galaxy filled with intelligent life, some of it a billion years more advanced than we are.
   But this is a lonely picture, too, because none of these civilizations can visit each other. That's why they're forced to communicate by radio, and why it makes sense to listen for their signals. They can't visit each other because, again, the distances are too vast. Journeys would take too long, and would require too much energy. Life, therefore, evolves in isolation all over the galaxy, progressing far beyond us until, as Drake suggests, many races achieve immortality. But still they can't visit each other.
   If this were a movie, we'd hear music swelling on the soundtrack. But does Drake's reasoning make any sense? He's talking about races a billion years beyond us. How can he know what they can and can't do? How could anyone know? There's a smug undertone to the SETI literature. All these scientists freely admit that we don't know anything about life beyond the earth. Then they suggest that, if life really does exist, much of it would be ahead of us. Next thing you know, they're telling us how these civilizations live.
   Somehow, a mystery has evolved into something much more comfortable. We sit in our theoretical armchairs, setting rules for the universe. And one comforting corollary is that, if these vastly powerful races can't visit each other, they certainly can't visit us. The way it works out, in fact, is that we, with barely two hundred years of technology behind us, are going to reach out and discover them . We won't have the messy embarrassment of them finding us first. To quote Jill Tarter, an astrophysicist who is another SETI leading light: "I have a closed mind on the idea that [UFOs are] a manifestation of extraterrestrial visitation."