ABSTRACT
This chapter focuses that logic is often concerned not with the question of which arguments are, from the viewpoint of logic, correct, but rather which are incorrect. The impression that logic is able to straightforwardly determine incorrect arguments may also be wrong for another reason. The most basic feature of this strong concept of logical incorrectness is that every logically incorrect argument is incorrect. This was a basic desideratum for strong in contrast to weak logical incorrectness and our definition does fulfil it. However, logical incorrectness, according to us, is a matter of the reflective equilibrium to the same extent to which logical correctness is. It is also the case that all arguments logically incorrect in this strong sense are incorrect for 'logical reasons'. Diagnosing an argument as logically incorrect is a nontrivial matter; it does not only concern arguments that are trivially incorrect.
