I'm taking a temporary break from the current Canon vs. Fanon topic – The Care and Feeding of Archeologists – to address another aspect of fanon that has cropped up frequently in the last several posts. It also happens to be an aspect of fanon that utterly infuritates me at times, so I figured I might as well get it out of my system!
This topic is a little complicated, so we'll take it in sections.
Recap: Canon is defined as anything we see onscreen during Stargate: The Movie or episodes of the show; show supercedes movie when there's a contradiction. (The Goa'uld are snake-like creatures that wrap round the host's brain stem and spine, not whitish, Roswell-like creatues with pointed teeth). Fanon is defined as widely-accepted concepts that often appear in fanfic, but do not have any actual basis in canon.
So, the question is: When is canon not proof of canon?
We can divide the episodes of Stargate into four categories, with a single exception.
1. Episodes that take place in real time, within the framework of reality, with the characters in full control of their behavior.
2. Episodes that take place in real time, within the framework of reality, but with the characters under some kind of alien influence.
3. Episodes that take place either within an alternate reality or a separate timeline.
4. Episodes that do not actually take place within reality.
[The single exception is the episode 200, from Season Ten, in which reality and meta and parody are so insanely mixed that it's impossible to tell if any of it actually happened at all. In fact, as far as I'm concerned, the single unquestionably real event in that episode is that Daniel got new glasses.]
Any episode that falls into the first category can be used to offer canonical proof of events, behavior, personality, tastes, and motivations. This includes, confusingly enough, the events of TBFTGOG and POV, because those are alternate universes within the frame of the regular reality of canon.
Any episode that falls into the second category is a little more tricky; some canonical proofs are still valid, but many will not be. Depending on the circumstances and strength of alien influence, anything from motivation to taste to characterization might be compromised.
Episodes in the third category are highly suspect in terms of canonical proofs. Like the second category, the degree of validity depends on the divergence from "regular" reality; but by its very definition as an alternate reality/timeline, the characters have undergone enough differences in life experience that any action undertaken might not be reasonable from the in-canon character's POV.
Episodes in the fourth category cannot be used as canonical proof at all. While they might grant us some insight into the characters' psyches, authors that use unreal events to back up their stories are creating something that's – well – unreal.
(Spoilers for Seasons Nine and Ten are bracketed by warnings in red.)
( Under alien influence )
( Alternate timeline or universes )
( Things that didn't happen )
My personal fanon opinion? Authors have over two hundred episodes as canonical source for their characterization of Sam, Teal'c, Jack, and Daniel. Even those episodes that don't fit the mold – whether it's due to alien influence, different timelines or universes, or non-reality – can be sources of insight; and, of course, the characterization can be used for fanfics that are directly related to those episodes. But please: remember what's real and what's not, and write your stories accordingly!
"Anyway, I'm sorry, but that just happens to be how I feel about it. What do you think?"