We present a logical framework allowing us to express assessment offacts (is it proven?) and arguments (is it sound?) together with a proofsystem to answer these questions. Our motivation is to clarify the no-tion of validity in the context of logic-based arguments along differentaspects (such as the formulas used and the inference scheme). Origi-nality lies in the possibility for the user to design their own argumentschemes. We show that classical inference obtains when arguments arebased on classical schemes (e.g. Hilbert axioms). We go beyond clas-sical logic by distinguishing “proven” formulas from “uncontroversial”ones (whose negation is not proven). Hence a formal definition of afal-lacious argument: it uses controversial formulas or schemes recognizedas illicit. We express some rational arguments and fallacies in the formof schemes.