(continued...)
It seems to me that a big part of what an explanation does is reduce the unknown to the known. So arguably, for an explanation to be successful, it will have to be capable of restating the unknown in terms of concepts that are already possessed and accepted.
You are arguing, in effect, that it's impossible for us to ever discover anything new in the world. Clearly, that is not the case.
Besides, we already have "known" concepts of "alien" and "alien life" and "alien spaceship". We know what sorts of characteristics we might reasonably
expect those things to have. An alien spaceship will need to fly. It will need to use energy to fly, somehow. It will need to be able to travel in space. It will need to be able to be guided to where the aliens want it to go, somehow. etc. etc.
There was a time when x-rays were undiscovered and unknown - only 100 years or so ago. Some people might have had fantasies of being able to see inside a person's body without breaking the skin, but those were just fantasies, reliant on unknown magic. And then, almost by accident, x-rays were discovered. Why do we now believe in x-rays? First and foremost, we believe in them because certain observations are
explained by postulating the existence of those "invisible rays". x-rays are scientific because we can generate them in reliable, repeatable ways. We can detect them in reliable, repeatable ways. They behave in reliable, repeatable ways. We can do reliable, repeatable experiments with them. Everybody agrees on how x-rays behave (in many sets of documented circumstances and under many different sets of documented conditions).
Did our explanation of x-rays "restate the unknown in terms of concepts already possessed and accepted"? In part, certainly: we wouldn't have called them "rays" if we didn't have a prior concept of a "ray", for example. However, initial hypotheses about x-rays were many and varied. There was no consensus, initially, on what x-rays were, exactly. These days, such a consensus
does exist. It relies on some "prior" concepts, as any explanation must, but
also on concepts that were completely unknown at the time x-rays were first observed.
So, it is not true to assert that science only deals in concepts that are "already possessed and accepted". Concepts
become possessed and accepted in science
because they work and because they are consistent with everything
else that science knows about our world. Science is a self-consistent body of knowledge. Certainly it has its core assumptions and axioms, just like every other kind of knowledge. That is not a flaw or a failure.
On one hand that's inevitable, since we can't comprehend things unless we already possess the concepts with which to comprehend them.
Not true. See, for example, x-rays. There was a time in the not-so-distant past when they were
not comprehended.
Now they are very well comprehended (in the corpus of human knowledge in general - not so much by particular non-expert individuals).
The growth of our knowledge is a boot-strap process: we have no choice but to procede from where we are currently at.
Can you suggest any practical alternative?
But on the other hand the so-called "pessimistic induction" seem to be a pretty strong argument against the idea that objective reality must necessarily conform to our current beliefs and concepts.
Who is making the claim that objective reality must conform to our beliefs? Don't you have that backwards? I think our current beliefs should conform with reality, as far as possible. Don't you?
Of course it's possible to be more speculative in our explanations, reducing the unknown instead to hypothetical possibilities. An open-minded freedom to hypothesize expands the conceptual space from which possible explanations might come. That's often how it works, and searching for evidence to 'confirm' (another can-of-worms there) these speculative hypotheses seems to be one of the major ways that knowledge grows. It's the essence of both trial-and-error and the so-called "scientific method".
See, for example, x-rays.
But isn't the idea that UFOs are vehicles created by space aliens exactly that? A speculative explanatory hypothesis?
Yes. There's nothing wrong with the mere hypothesis.
So why all the insults, sarcasm and bullying towards anyone that proposes it?
I think you'll find that criticism tends to be directed at those who claim that the hypothesis is certain, very likely, or more-probable than not, based on shoddy evidence.
You might like to ask yourself why somebody like MR gets so upset every time somebody suggests that today's favorite UFO sighting might be the planet Venus. That's a speculative explanatory hypothesis, too - and a far more likely one than the alien spaceship one.
Presumably, there's some additional criterion at play here that determines what is and isn't an acceptable speculative hypothesis. So what is it?
There isn't one. All speculative hypotheses are fair game. We decide between them by critically reviewing the evidence for and against each of them. If there is insufficient evidence for any particular hypothesis, we should be careful not to make exaggerated claims that the hypothesis must be true.
Don't you agree?
As always, my own tendency in these matters is to adopt an attitude of friendly, curious agnosticism.
Great! Just make sure that mind of yours is not so open that you let your brains fall out.
If we want to procede scientifically, we should be emphasizing the issue of what kind of additional information do we need to make a better determination about what these things are. Which is precisely what NASA was doing this summer.
You'll see no argument from me on that. It's only people like MR who believe they already have all the information they need to make a positive ID on every UFO.
I welcome free expression of all hypotheses in the 'fringe' fora, although I am unlikely to personally accept many of them as plausible if they contradict my own beliefs about how reality is. Ghosts might fit that description.
I reject ghosts (at present) because there is no convincing evidence that they exist - just like alien spaceships visiting Earth. That has nothing to do with any special bias against spirits of the dead. I am willing to revise any opinions I might have about the existence of a ghostly afterlife just as soon as you present me with convincing evidence that such a thing is real.
But the fact that I don't believe in spiritual survival of death doesn't mean that I summarily dismiss reports of uncanny apparitions.
Nobody does. Well, okay,
some people do. But, on the other side of the coin,
some people think every shadow is a spirit. I recognise that you and I don't fall into those categories of unreasonable belief - or unreasonable dismissal. You are yet to recognise this - or are yet to admit that you recognise this. Instead, you prefer to tell your Big Lie. Why?
It certainly doesn't mean that I will try to shout down those who argue for ghost sightings with insult and invective.
Who has been shouted down? Can you give any examples of such a thing happening on sciforums, for instance?
Has MR, for example, been deterred from posting daily about UFOs?
What I wonder is: why do you think
you need to imagine that skeptics are bad people, while giving woo peddlars, liars and charlatans a free pass?
