In every day as well as in legal and scientific discourse there arearguments which refuse to be analyzed by means of formal logic. Onesuch class of arguments are so called "presumptive" arguments.Arguments of this kind are neither deductively valid nor inductivelystrong, but they license presumptions which can be used as a basis forrational action. They are non-monotonic, tentative and they shift theburden of proof to the other party in a dialogue. It is unclear ifpresumption is a class of inference sui generis, as deduction orinduction. However, many such arguments take prototypical forms -- theyrepresent certain "argumentation schemes". A set of critical questionsis linked to each of these schemes, which can be used to evaluatearguments, instantiating that particular scheme.The objective of this thesis is to explicate the notion of presumptivereasoning and the evaluative role of argumentation schemes. First, theuse of schematic arguments and its effects on the distribution of theburden of proof in a dialogue will be investigated. Then, an exemplaryevaluation of an argument will be given. Finally, some opentheoretical questions will be discussed.