something that's kind of different about x files, and that i think i heard some of the writers talk about on x files diaries podcast, is how there are the 'stand alone' episodes aka monster on the week and the mytharc/mythology episodes. the standalones don't move the plot forward, are very self contained and you don't necessarily see a character or relationship progression episode to episode. scully & mulder's roles are way more set in these, typically. mulder, believer. scully, skeptic. but it makes sense, it works! every one of these episodes is something new that they haven't seen before and will need to be proven all over again. like @cthene said before, the existence of one creature doesn't prove another exists. the longer the show goes on, the more they'll recall other cases. there's always something sprinkled in. some little in jokes. like in soft light when they check the vent because of tooms, and scully's former student understandably questions it lol scully believed in the anomaly that tooms was. she knows mulder was right about fingerprints and she spent quite a bit of time with the detective who worked on the case decades before. personal connection is important for her ability to believe. as well as proof. (two things which i think make her feel safe, and in beyond the sea scully tells mulder that she's afraid to believe.)
so, one of the reasons i love the mytharc is because different rules apply. they're connected and we can see the progression. consistently, mulder and scully are making the connections and remembering. scully doesn't hesitate to believe the same way. she still argues mulder's theories, and is extremely (rightfully so) skeptical & distrusting of mulder's informants, especially of their motives. but she isn't denying what's happening. she works hard to follow the evidence and get proof.
season one mytharc are all the building blocks they're going to use. the implants, different abduction stories, connections to government & military, mulder's inside informant, and bits of information that come back. deep throat dies at the end, but his presence doesn't disappear — mr. x talks about him, we see him again in mulder's dream in amor fati, and they see his grave in the revival. in season two, despite being taken off the x files, scully fights to keep mulder as her friend, help him at work, and work with him whenever possible. he eventually finds ways to work on the x files with some assistance from skinner, and eventually scully is abducted. with the help of our good friends duane barry (with the implant), alex krycek and csm! while duane barry dies, csm was established as a shadowy figure in the pilot and he's present throughout, his connection more menacing & personal than we could have guessed in the beginning.
scully is skeptical from the beginning, that's very true. but she listened to mulder in the pilot. she didn't believe his sister was abducted by aliens, but she was touched by how deeply it marked him and his passion for justice and the truth. she wanted to help him. she cares about justice & the truth too. it's how she ended up in the fbi. it's how she ended up as a pathologist too. in paper hearts, they have to face what scully feared was what really happened to samantha. in season two, scully went through some of what really happened to samantha and she couldn't remember it. scully became inextricably linked to her even without mulder. she made the x files her work because of mulder and because it felt right to her. and then it became personal to her over and over.
you can see scully's belief every time mulder is in danger. she doesn't hesitate to believe in aliens, alien viruses, government conspiracies, etc when mulder is in danger or they're in the thick of a case. she actually pushes hardest against it, when it concerns her own abduction. until patient x and the red and the black. after her cancer. after emily. long after the point of no return.
she still plays her role. she's the scientist. after fight the future, after taking time to misunderstand what mulder meant lol, she thinks she has to double down on her science & skepticism, she has a bit of a backslide. it isn't that she doesn't believe everything they've discovered & experienced, but she thinks mulder needs her to keep him honest, to stick to the science and find the proof. that she can't let him change her. that's why season six becomes the transition season. where they're realizing these strict roles don't work for them anymore. mulder has told scully before that she taught him he needs the proof. scully has been the believer but every time it terrifies mulder (sometimes rightfully, sometimes just because he doesn't understand that side of her), or he's deep in his own struggle with belief. season five, i think he started to learn it was okay. season six he was learning that sometimes, at least, he needed her to believe. and in season seven, he starts to actually embrace her belief -- and soon after it becomes very necessary for her. to keep going on the x files without him, to be able to do their work and to keep going for their son. to not give up sop she's still there when he comes back.
i love the way you can see them change most in the mytharc. the episodes carry more weight, are (typically) more personal, higher stakes. there's a consistency in what they're dealing with, everything is connected and they learn how slowly over time. and they see proof, they just never get to hold onto it. and they both experience undeniable things and come back from death's door and defy all science & logic. something mulder tried to tell scully in the pilot but she had to see for herself, because that's who she is.
(anyway. both of them were always going to be abducted!)
