In the pragma-dialectical approach to argument schemes, each argument scheme represents a particular justificatory relationship that is supposed to legitimize a transfer of acceptability between a reason (or coordinative set of reasons) advanced in defence of a standpoint and the standpoint that is defended. The various argument schemes that can be used in an argumentative exchange and the way in which their use is to be evaluated are in principle considered to be part of the joint starting points that are by intersubjective agreement established at the opening stage of a critical discussion aimed at resolving a difference of opinion on the merits. This contribution recapitulates and extends the rationale and general outlines of the pragma-dialectical approach. It is the first instalment of more encompassing series of studies that is to result in a monograph offering a complete overview of the treatment and categorization of argument schemes.