# Can you use a theory or rule to prove that exact theory or rule is wrong?

My question is this: if say I have a rule `R`, is it logically possible to prove `R` is wrong using `R`? Or is it simply not possible because if the hypothesis (that `R` is wrong) is true, then proving `R` is wrong using `R` may not be true either. However, conversely, if `R` is wrong, and I cannot prove that `R` is wrong as a result, then I also cannot say `R` is absolutely wrong. This is a rather complicated and mind-boggling logic question, and I would like any insights or possible break-through points in this logic circle. Thanks in advance!

• “There are no maxims”? Is that logical enough or do mean something with more rigor? Commented Jul 24 at 6:17
• Yes. "Talk, but do not talk" is self-contradictory and hence 'wrong', as is any self-contradictory theory. This is neither complicated nor mind-boggling. Commented Jul 24 at 6:27
• This is called reduction ad absurdum, it's used commonly. Commented Jul 24 at 6:35
• Usually to prove or disprove any hypothesis R you need other evidence other than R itself to break your mentioned obvious logic circle, and the evidence alone could be significant enough or by further new evidence powerful enough to argue against R. If R is an inadmissible rule in a logic system, it can be proved wrong by other axioms and rules. If you want to prove R is wrong by using R itself in a transcendental sublime philosophical way, Kant in his CPR demonstrated using pure reason to critique pure reason itself is possible without harm... Commented Jul 24 at 7:02
• truth is a complicated issue... maybe relevant Grounding for the metaphysicala spects. From the "strictly logical" point of view, we have to consider that it is simply impossible to prove everything. Thus, we organize our work with theories, systems, etc. We can discuss the rules of a specific system using another system, but inside a system an axiom/rule is simply assumed and not proved. Commented Jul 24 at 11:07