Here’s the Internet Speculative Database for the first edition of the book
Publication: Dragonflight, which notes that
“An in-universe introduction is on pages ix-x”
And here is a link to a Google books excerpt from Analog, 1967, showing part of the introduction quoted by Fenris above Analog Science Fiction/science Fact - Google Books
All the “fantasy or science-fiction” debate is kind of moot, since the most fantasy-like elements of Pern are in the first book and are minimized thereafter By the second book in the series, the principal characters found some remnants of the original settlers, and soon after that, they are excavating the landing site.
It’s like taking a big permanent marker and scrawling “Science Fiction” on a fantasy novel. It’s an affirmative declaration, making use of certain commonplace terms, but it just isn’t convincing.
True. And, really, it doesn’t matter a hang. I’m mostly reacting against McCaffrey’s (mere et fils) strident insistence.
A much stronger case could be made for Jack Vance’s “The Dragon Masters,” where the dragons are alien animals bed for combat. And that novel, too, is often categorized as fantasy.
The debate itself is pointless, as categories are incredibly fuzzy. But, c’mon. Time travelling telepathic flying fire-breathing dragons partnered with people who cast magic spells. That doesn’t mesh too well with, say, “I Robot” and “The Caves of Steel.”
My reckoning is that I accept what the book is telling me about whether it is fantasy, or science fiction in fantasy drag. Pern clearly sets out to be a (squishy soft) science fiction setting. Shannara is explicitly a “magic returns to the world” fantasy setting (although perhaps “science” shows up in one of the endless tide of Shannara sequels; I’m certainly not reading the damn things to find out, though).
And to shift the thread away from the fantasy/SF debate…
I don’t think Menolly is a Mary Sue. Sure, she’s the central figure of the Harper Hall books, but after she grows up, she’s pretty much much a minor character in the Pern books. IIRC, after the Harper Hall Trilogy, I don’t think McCaffrey tells any of the narrative from Menolly’s point of view. If McCaffrey was a man, I would say Robinton is a total Mary Sue.
As an aside, I was surprised to see that more recent editions of Dragonsong and Dragonsinger depict Menolly as blond on their covers.
If saying that something is set on a planet in outer space makes a story science fiction rather than fantasy, then Discworld is science fiction, too.
Now, this, I agree with. 
Oops. Sorry. Tedious, I know.
Can I recoup just a little honor by mentioning, again, how really super nifty a guy Todd McCaffrey is? He’s a favorite in the southern California convention circuit, and absolutely the nicest guy on the planet. Funny, too. His readings are to die for, and his comedy is gold.
So if he’s a favorite on the southern California convention circuit, does that mean that he lives there now? I was assuming that he inherited his mother’s house in Ireland and now lives there. Back in 1995 I actually visited that house. I was on a tour group of American science fiction fans who were headed to Worldcon in Glasgow. An American fan who had previously worked as a travel agent organized the trip. We individually flew into Dublin and then traveled around Ireland (going clockwise) by bus, seeing the usual sights. When we got to Belfast, we flew to Edinburgh and did some sightseeing. Then we traveled to Glasgow, where the tour ended and Worldcon started. We individually flew home from there.
But, anyway, early in the trip we visited the homes of Anne McCaffrey and Katherine Kurtz. (Kurtz has since moved back to the U.S.) My memory is that Todd was living with her then. I had assume that since he inherited the Pern series, he also inherited the house. Of course, Anne had two other children, so perhaps each got a third of the house when she died and they decided to sell the house.
The reference isn’t to the equation - Arrhenius was also a proponent of panspermia
I believe so. He’s usually at LosCon, and at Comic-Con, and in February, he was even at ConDor – which is tiny. No way he’d travel from Ireland for that one! I have no idea what the status of the house or property would be. (He inherited the good property: the license to write stories in Anne McCaffrey’s worlds!)
What type of story do ridiculous straw men arguments make?
What if you say that the story is about a lost colony who lost their tech rediscovering it’s old tech and heritage with the help of native creatures that the original colonists genetically enhanced and modified. And then dealing with the vast societal changes that occur as a result of jumping from late bronze age tech to late 1700s tech in a single generation?
Have you ever actually read the books? I mean, seriously–lost tech figures in from the prologue on, and yeah, while the first 2/3ds of the first book deal with the social revolution needed to start rediscovering the tech, the other books in the series all deal with rediscovering lost tech (and the end of the first book touches on it).
Yes, but that’s all far secondary to the dragons. Cut out the lost tech and leave the dragons, and you have basically the same story. Cut out the dragons and leave the lost tech, and it’s completely unrecognizable.
Heck, Lord of the Rings had long-lost technology, too.
No. You don’t have the same story at all, except in the first 2/3ds of the first book.
Every book beyond the first 2/3ds (3/4ths maybe) of the books deals more and more with the tech–hell, a huge chunk of book 2 involves the ramifications of discovering telescopes* (and flamethrowers). And book 3 is largely about exploring another continent and discovering more old tech.
A more valid statement would be: Cut out the dragons and replace them with flying cars that can teleport and you have the same story, except for the first 2/3ds or so of the first book. The “I wuv my wunderful dragon” stuff is there, secondarily, in later books but except for the first book and a plot point (a stolen queen dragon egg) in either the 2nd or the 3d, the dragons are transportion, not plot-points.
*Teleporting requires a mental picture of where you’re going. The “red sun” seen through a telescope suddenly has features that can be made out. Suddenly there’s a huge social push to have the dragonriders teleport there and wipe out the thread at the source. “Exploring how a tech innovation affects society.” One of the classic definitions of SF.
Duplicate post-ignore pls
The “Shadowrun” universe is a mixture of magic and technology. I don’t get this binary “either/or” mindset. 
A deep concern with the “dividing line” is probably rooted in different things for different people. Some, clearly, are using it to define themselves (and claim a certain place in the pecking order). The assumption for such people is that fantasy is an inferior genre, one that the claimant would NEVER stoop to read.
Another possible reason for wanting to divide fantasy from science fiction: a conviction that fantasy plotting always involves contrivances, aka ass-pulls. I’m not the biggest consumer of fantasy by any means, but even I don’t believe that authors who posit the existence of Magic are automatically to be considered lazy or lousy plotters.
(Some are, of course. But that’s true of some writers of science fiction, too.)
Personally, I’m not a believer in the supernatural. So authors whose stories depend upon the supernatural for effect have to get some pretty glowing reviews for me to be willing to give them my time (let alone money).
Actually, I’m pretty concerned about where the dividing line is. And I don’t consider fantasy to be inferior. I read both fantasy and SF, and my SF favorites range from very hard indeed (Robert Forward, Vernor Vinge) to quite soft and squishy (Sheri S. Tepper, LeGuin, etc.). Yes, I like pigeonholes.