In fact, many research findings concerning medical mechanisms cannot be directly proven; at most, experimental data can be made public for everyone to discuss and analyze. However, as long as they do not conflict with officially recognized basic research, they can be considered correct.
Medicine is not mathematics.
Mathematics requires detailed proofs that delve deeply into simple problems for repeated discussion.
No matter how many conclusions support the correctness, without an absolutely logical proof, they will be categorized as hypotheses or conjectures.
Medicine is different.
Although medical mechanism research also requires rigor, because the goal of medical research is to apply it in practice, as long as the results are effective in practice, that's sufficient.
For instance, if drugs or treatments based on mechanism research directly prove effective, the mechanisms can be considered correct.
Moreover, not conflicting with established results is also vitally important.