Pathological science is a term that refers to research characterized more by obsession than by results.
It’s something that most of us are probably subject to, to one degree or another. Many researchers, even hobbyists and enthusiasts, want for some one result in particular to be true. They’re always on the lookout for data that support their desired conclusion. This is not, by itself, pathological; but for some who take it to an extreme, it can become that way. Many famous cases of pathological science began as legitimate science, and often the researcher would become distracted by tiny results that suggested an effect when in fact there was none. Belief supplanted objectivity, and the science became pathological science.
The term was first publicized by Nobel Prize-winning chemist Irving Langmuir in 1953, in a talk he gave discussing such cases. Anyone with an interest in scientific skepticism will immediately recognize the applicability of the term to many pseudosciences. In my own research of hundreds of pseudoscience cases, I’ve encountered many researchers who left the path of science in favor of wishful thinking. This includes legitimate professionals who get sidetracked by a poorly-supported belief, and also many armchair amateurs who often turn their beliefs into careers (think alternative therapy merchants, fad diet promoters, perpetual motion enthusiasts, Bigfoot and ghost hunters, and guys who think they’ve proven Einstein wrong).
A pathological science is usually triggered by a weakly positive result that is especially intriguing. For a scientist, this can be a result in a well-controlled experiment; for an amateur, it can be a personal experience that is misinterpreted or influenced by biases or external factors. Both compel further experimentation, and when the scientific method is thrown to the wind in favor of an emotionally-driven method — and the process becomes prolonged — a pathological science can result.
A pathological science differs from a pseudoscience in that it’s more about the method than the results. A pseudoscience has no sound foundation, or has perhaps even been proven wrong; whereas a pathological science is one that is single-mindedly pursued and driven by exaggerated results that do not justify the continued research. A pseudoscience is defined by its lack of validity; a pathological science is defined by the lack of its method’s validity.
In his famous 1953 talk, Langmuir described several such cases, and there’s a decent Wikipedia article that describes them, notably one where a physicist became so convinced of the reality of “N-rays” that he believed he saw positive results even when his machine was disabled. In shooting The Skeptologists, we pulled a really cheap trick on the ghost hunters who accepted it immediately as evidence of a ghost, when even the most basic application of science would have prevented such a conclusion. Television Bigfoot hunters accept practically anything as evidence of Bigfoot. All of these people are practicing not science, but pathological science. They’ve blinded themselves to any results but those which support their desired conclusion.
I try to take a lesson from these folks. I always keep in mind that I’m human and no less error-prone than anyone else, Bigfoot aficionados included. When I’m researching a old legend and I find the taste of hoax in the water, it’s easy to relentlessly pursue that hoax explanation. I could easily become a pathological “debunker”. What keeps me sane, I think, is the way I enjoy the unexpected roadblocks to the obvious explanations, and twists and turns that show even the popular “scientific” explanation is probably not right. Pursuing one desired result does not interest me. Finding new alternate explanations and turning over new stones does interest me. I suppose that, if anything, I’m at risk of becoming a pathological obscure-fact-finder.
Whatever your area of expertise, keep this possibility in mind. Never set method aside just to encourage a repeat of an oddball result. Keep your pathology and your science separate, such that never the twain shall meet.