In a certain field of science, it has been known that X leads to Y and assumed that if Y is observed it is caused by X. Using a relatively simple (mathematical) experiment, I have shown that also A, B, C, ... (class of certain objects), lead to Y, which means that observing Y does not guarantee X.
In my opinion, this is something that should have been checked years ago. In fact, this finding can be used to refute or at least considerably weaken the work done in a certain sub-field over more than 10 years. (though there's some prior critical work on this but the people do not seem to have cared)
Is it usually possible to publish such findings in leading journals?
Another problem that I have is that the work challenges a major part of my supervisor's work, which rests on the mentioned assumption. She seems quite upset, and tries to see the work just as some technical quirk, which it is not. I joined the lab quite recently, so I have no idea what to do. Anyway, I am very serios about this: I'll resign if it necessary to get thing published as soon as possible. It could even end my career altogether but if science is not about truth I don't see why I would like to stay in it.
I am very early in my career and the most technical (mathematical) person in the lab. What I have shown is kind of similar as finding a counter-example in math.