How to describe arguments in fundamental criteria for good arguments?

How, in particular how abstractly, should arguments be described in fundamental argumentation-theoretical criteria for epistemically good arguments? In order to answer this question, it is first clarified which conditions must be fulfilled by epistemically oriented, adequate argumentation theories. Then, five differently abstract ways of describing arguments are presented, including argument schemes and characterisations of argument classes. Next, it is shown that theories of argumentation that formulate their fundamental criteria for good arguments in terms of argument schemes cannot be epistemically adequate, whereas theories that use characterisations of argument classes––as epistemological theories of argumentation do––can be. This is a strong argument against argument schema approaches in argumentation theory and in favour of epistemological ones.