I think it's an identity thing. For basically political reasons, we're predisposed to believe that groups with which we identify can, at least to a first approximation, do no wrong -- and if that group organizes itself along aesthetic lines, as with science fiction fandom, then that means any respectable media it includes under its auspices must be seen as aesthetically enjoyable (plus whatever other criteria your group uses). When you run into some piece of media that you don't like but which otherwise mostly meets the criteria, the easiest way to resolve the resulting cognitive dissonance is by confabulating some reason to disqualify it. Get a thousand people together with different standards of taste but a shared literary identity, and that gives you a recipe for some pretty vicious definitional disputes.
(It'd make sense to me if people formed those standards of taste from a few early emotional highs, but I don't think that fully explains their ardor for a definition. I propose you get that from taste plus identification with taste.)
This generalizes pretty well to non-fandom identity groups, too -- any group that aligns itself around (hat-tip David_Gerard) a fuzzy cluster in thingspace that's complicated enough for different definitions to identify most of the same cluster, and dear enough to its members to form a substantial part of their concept of self.
I've always thought of this in terms of extension of the ego boundary. Humans treat dearly loved ideas and objects like limbs.
I have identified myself with many subcultural groups over the years, and in pretty much all cases fallen flat on my epistemological face when I tried to solidify their definition speaking to others and not just in my head.
Some subcultures have their own undefinability as a subcultural trope, e.g. goth, which has excellent "I knows it when I sees it" but is notoriously unable to develop a concise definition those identifying it would put up with. (Including the author of this excellent and otherwise spot-on book, who spent a page and a half expertly dodging giving an actual definition. I called him out on this and he admitted it and laughed. Gah! He notes that if you ask two goths for a definition, you'll get four answers.)
The LW concept of "fuzzy clusters in thingspace" has been most useful to me in thinking about these things.
Off-topic: how did you feel about Ballard and Moorcock? (The latter's SF-leaning stuff, not the fantasy-leaning stuff.) And the New Worlds bunch in general.
(I've been getting back into Ballard since rejoining the JGB list, a remarkably high-quality list. Full of Ballard's editors, translators and people who write books on him ...)
I think "fuzzy clusters in thingspace" is sound, but it doesn't explain why people get so emotional and rigid about definitions.
I liked some Ballard in moderate doses. I remember "Chronopolis" fondly, and the one about breaking the time flowers to keep the barbarians away-- for a while, and something about orchids which produced music and (same series, I think) cloud sculptors.
I don't think I read much of Moorcock's science fiction. I liked Gloriana, but bounced off Elric.
More generally, at the time I saw a hard split between writers I liked who I thought were just writing science fiction (perhaps with fancier prose, but I wasn't terribly sensitive to that) and who I couldn't figure out why they were classed with writers I detested or couldn't see the point of (David Bunch).
These days if I see contemporary writing that looks like New Wave, I get a little nostalgic even if it's the sort of thing I otherwise don't like.
By the way, I didn't think of mentioning specifics of sf as trolling, but I did think of it as rather like dragging the cat toy along the floor.
Reading the post title caused in me a knee-jerk association with the BSP episodes: Review of "The First Idea" by Shanker & Greenspan (based on The First Idea: How Symbols, Language, And Intelligence Evolved From Our Primate Ancestors To Modern Humans) and Bonobos with Dr. Stuart Shanker.
I used to read discussions of the definition of science fiction until I came to the conclusion that there was no point.
Is it just that the ramifications of one definition vs. another have little impact that makes you believe there is no point? I mean, definitions of sf are not a pressing concern for humanity, but if sf aficionados enjoy a healthy debate about the finer points of that particular genre, I don't deem it pointless. There are similar debates about whether or not Robinson Crusoe was truly the first example of what is known as a novel today.
I don't know the origin in a given person for the impetus to care about something like the definition of sf. It could be emotional experiences at a young age, or at an old age. Whatever it is has to give them a feeling of being invested in the topic.
I'm more interested in the generalization of this to other concepts. Imagine if someone said, "I used to read discussions (of the origin of life) until I came to the conclusion that there was no point," or "I used to read discussions (of concept-X-which-may-or-may-not-have-far-reaching-social-or-technological-consequences) until I came to the conclusion that there was no point."
I don't mean this as any sort of criticism at all. I probably would have the same reaction you do towards definitions of sf. I guess what I am asking is maybe we should be thinking about the dual of the question in your post. When can Concept-X be readily dismissed as inconsequential in its nuances, and what then to make of people who don't brush off Concept-X?
It's a fair question.
Let's say that I no longer think there's any point in doing that for recreation. One of my friends has a definition of science fiction which is very different from mine, and it's very hard for me to keep from arguing with him about it.
There are cases where these definitions are literally a matter of life and death. One of the hot issues in feminism is whether someone who's male-to-female transgendered is really a woman. This affects policy in shelters from domestic violence.
This might be essence of mind-killer territory-- even more so than practical politics. And I don't think feminism is especially prone to it-- national and religious identity play out the same way.
I just realized a few hours ago that what identities one is willing to attribute are part of one's own identity.
Edited to add: And I bet that if "rationalist" becomes worth anything in the larger world, we're going to be dealing with these issues.
This is a theory I find plausible-- I don't know if formal work has been done in the area.
I used to read discussions of the definition of science fiction until I came to the conclusion that there was no point. People have strongly felt intuitions about what science fiction really is, and seem to have no way of knowing that everyone doesn't agree until they bump up against other people's definitions.
But why would one have a strong attachment to a definition of science fiction?
I suggest that people invent such definitions from a few early, emotionally charged experiences.
I still find it hard to believe that Delany and Zelazny really wrote New Wave science fiction, when their vivid and enjoyable stories were so different (for me) from the likes of Malzberg (dreary) and Aldiss (mostly boring).
I suspect matters are more extreme in visionary politics. One's ideas of a drastically better society are (usually?) derived from an unconscious mix of what seems better and possible, and if the vision is strong enough to lead to action, then it's got to be strongly felt. The unconscious mix is idiosyncratic, and it can be shocking to find out how different the visions are for people who group themselves under the same political label.
The only thing I can think to do with this theory is to hold a little lightly to definitions rather than look for the one true definition, and to ask people about their prototypes for concepts rather than definitions.