There is the "Believer" career for religious nutjobs. "Truther" is for nutjobs who are not religious.
Both are defined by believing in something without evidence it is true - this differentiates them from scholars and journalists, in that scholars' and journalists' skill sets provide them with methods for discovering truth, while believers and truthers won't have or need these kinds of methods since they already know what the truth is, to their own satisfaction at least. The difference between them whether you just make up your own crazy theories, sometimes in conversation with others who follow similar but not necessarily the same theories, or follow the crazy theories made up long ago by others. Also, Truthers will tend to imitate scientific jargon. Believers will rely more on magical explanations and discourse. Both rely on the psychology of making adherents feel specials and chosen, as the only people who understand secret hidden truths, but for believers it is more of a collective delusion providing membership in a community of wingnuts, while for Truthers it is looser and more individual: there may be a community but the ideology is less dogmatic and fixed, and more subject to innovation through people "doing their own research" and thereby making up new "facts" which can alter the belief system. For Truthers, there is more likely to be a haze of "truth", and individuals can adhere to some narratives but not others: for Believers, "doing your own research" and making up new "facts" is likely to run you into trouble with the powers that be for your cult religion.
Obvious crackpot theories for your Truthers to promote:
Flat Galaxy Theory: while so-called "astronomers" assert the galaxy is a three dimensional disc-shape, about 3000 light years thick in the area of Charted Space, what they don't want you to know is that it is actually perfectly flat, and better represented by a flat map.
Ancient Aliens Theory: Ancient aliens visited Earth long ago and influenced major events in human evolution. While Ancient Aliens Theorists exposed this as long ago as the 20th century, it was dismissed by conventional science as "Idiocy, Fabrications and Lies" (to quote the Smithsonian).
IMTU, my PCs have not shown interest in making a career of either of these, and for this I am grateful. Though one PC did adhere to a religion, but it wasn't his actual career or job. For NPCs, I've used the Believer career path for priests and other church functionaries, but also Scholar for theologians - because although it is not a real science, it does follow methods similar to philosophy, history and literary studies, or sometimes archaeology, in order, for example to engage with ancient religious texts. However, there seems to be a consensus among the PCs that not much would be lost if all the Theologians fell out the airlock one day by accident.
