A standard critical argument in my field looks something like this:
1. Phenomenon X involves A assumptions about the world;
2. Approach Y contains assumptions inconsistent with A; therefore
3. Y cannot be used to understand X.
In some instances, and given some specific conditions, this can be a persuasive argument. But it is clearly not a priori true; articulated in the form above, I submit, it is a logical fallacy–one often found alongside, but distinct from, genetic fallacies.
Thus, I will call this the “own-termism fallacy” until someone finds a better–or, at least, preexisting–name for it.
UPDATE: some have asked me for an example. As I’ve written about, this kind of reasoning is extremely common in the “secular bias” literature, which often claims that “secular” theories and methods born of the enlightenment cannot possibly make sense of religious politics.