'Logic' means the same thing in Europe and North America, as far as I'm aware. I think that a number of people in this thread are misusing the word 'logic'. I'd say that logic is the study of logical consequence, such that if a set of propositions P1, P2, P3 ... Pn logically imply a conclusion C, then if P1, P2, P3 ... Pn are all true, then C must be true as well. (It's important to note that this implicative relation can hold even if some of the P premises aren't in fact true, provided only that if all the Ps were true, the conclusion C would have to be true too.) I agree with that 100%. When we change physical theories we aren't typically changing the underlying principles of reasoning itself, the principles of logical consequence and implication that are embodied in mathematical as well as verbal reasoning. We are just adopting different premises that imply different conclusions.