Scully believes the key to true understanding is through science. She also doesn’t have the luxury to believe what comes easiest, as she needs to be able to explain it in her reports to their superiors. My answer is two-fold. One, is who Scully is as an individual.
Two, is who Scully is within the bureau.
We’ll start with childhood Dana growing up with an older sister who was very new-agey. Melissa Scully loves mysticism. I am willing to believe there was some sibling rivalry growing up in the Scully household, that led Dana to reject the things that Missy loved – starting Dana down her path of “hard science”.
She then studied sciences in school, where she learned not only how many things work, but about how many things we don’t yet understand. Much of science is still in the “we don’t really understand why this works yet, but it’s a large area of research in the community”. So Scully’s studies would have taught her that “just because we don’t understand how something works yet, doesn’t mean we can’t figure it out”. Scully herself often says in her reports that although science cannot yet explain what she has seen, she believes it is the way to understand what happened. For example at the end of Teliko, she writes: My conviction remains intact that that the mechanism by which Aboah killed and in turn survived, can only be explained by medical science, and that science will eventually discover his place in the broader context of evolution. She never denounces what she’s seen as absurd, but she isn’t going to say that it’s supernatural, either. Just a piece of science that we don’t yet understand. It's not that Scully doesn't believe. In the Pilot Mulder asks her if she believes in aliens. And her response is not “aliens are ridiculous”.
Her response is, ”Given the distances needed to travel from the far reaches of space, the energy requirements would exceed a spacecraft's capabilties th.
”. Her answer speaks to an understanding of space travel, and the probability of habitable planets besides our own. It also says, she’s given it thought, and with our current understanding of space travel requirements, and distances between habitable planets, it would be highly unlikely that aliens would come to Earth on a regular basis, if at all.
Episode after episode, Mulder will spout some theory, which is correct, but sounds insane, and Scully’s first response is often “Is that what you are want me to write in my report?” or “Is that what you are going to tell Skinner?”
Scully knows where the X-Files stands within the bureau. They are considered a joke by some of their peers, and a threat that needs to be portrayed as a joke by others. She knows she was assigned to the X-Files to repudiate what Mulder believes. So she knows she needs to find evidence to substantiate their claims.
She has to report on their work, and she needs to prove why what they believe is rational. Mulder loves jumping in, without worrying about rationality. He doesn’t care if something makes sense or not. He’s more of a “seeing is believing”. But Scully knows that when they write a report, to others who weren’t there to see it, they need evidence to explain what was seen. “You should have been there” won’t cut it. An example of Scully’s belief in contrast to Mulder: Think of the episode Tooms. Scully knows what Toom’s is capable of, because he distorted his body to squeeze through her apartment vents and attack her. But when they show up at his probation hearing Mulder starts talking about how Tooms was squeezing through tiny tubes and killing people to eat their livers. The court basically treats Mulder like a crazy person, and releases Tooms.
After the hearing, Scully says to Mulder “Do you know what you sounded like, in there?” His response was “I don’t care what I sounded like, as long as I told the truth. ” – Okay, well that’s all well-and-good Mulder, but maybe if you told the truth in a manner that didn’t sound unfounded and irrational, Tooms wouldn’t have been let out to kill more people!
This is why you need science: to show, not tell others what is the truth.
Scully believes many of the same things as Mulder, but needs understanding. If you understand the “why”, then you can explain it to others, without sounding crazy.