Mostly he debunks claims that UFOs are alien spaceships, by showing that they are, in fact, regular commercial aircraft, camera artifacts, weather balloons, or other "mundane" things.
Why do you think that "debunking" (literally removing the bunk from things) is a bad thing?
This is a good thing. As you say, it is standard practice in science. There's no point publishing your next great scientific theory if you haven't first bothered to imagine any of the ways it might be wrong. Because, if you don't do it, somebody else will, in science, and then you risk looking like a bit of a naive fool if you've overlooked a simple test you could have done or a simple observation you could have made.
I would use the word "uncertain". Part of any good scientific study is trying to quantify the uncertainty. If you set out to measure the speed of light, it is important to know whether you're able to get the right answer to within 1 metre per second, or only to within 100,000 metres per second. Either way, if your particular experiment differs from the average results of thousands of other experiments (within the bounds of your uncertainty and theirs), then the chances are very high that there's something wrong with your experiment.
Yes. The great thing about science, though, is that it has built-in mechanisms to filter out those personal biases and preferences over time. In contrast, the UFO believer community seems to have no such process, or even a desire to avoid confirmation bias.
As Magical Realist pointed out, the idea that aliens are visiting earth is very welcome, among a certain crowd of people. Some people manage to make a living from the active promotion of alien nonsense.
That's because they don't know much about how amazing reality really is. They prefer simple, comforting myths to complex, uncertain answers and to real mysteries.
Who are these "adherents of scientism" you refer to, exactly? I challenge you to find anyone who has stated publically that he or she believe he or she, personally, has all of reality nicely categorised in little boxes. That's equivalent to a claim to knowing everything. I think that, among the sane, you will find no examples of people who claim to know everything.
I think you will find that many atheists disbelieve in alien visitation for the same kinds of reasons they disbelieve in God - the main one being a lack of convincing evidence for the existence of any such thing. That has very little to do with any inherent lack of longing for transcendence, or whatever.
Why are you so keen to concentrate on the motives of the people making the arguments on both sides, rather than on the arguments themselves?
Here's what I think: I think that you know that the evidence for alien visitation is extraordinarily weak, but you still feel a kinship with UFO believers for some reason. Perhaps you feel that they are an unjustly persecuted minority. Perhaps you feel they are fundamentally fragile people who need your protection from the bullying "scientism" people. Then, since you know that you can't mount a good argument for belief in aliens, you try to defend the UFO believers by making ad hominem attacks on the skeptics, in the false belief that if you can show that they have bad motives or that they have goals or biases, they must be wrong, by default.
That, of course, is a completely fallacious line of argument. As a self-styled philosopher and "philosophical skeptic", you must know that.
No skeptic claims to know, beyond doubt. That straw man is part of your Big Lie. You know this, too. And yet, here you are, still pushing that line. Why?
