 A third contextual factor that may warrant comment in a supplemented diagram is the dialectical context in which an argument occurs. In his account of argument, Johnson 2000 distinguishes between the “illative” core of an argument and the argument’s “dialectical tier,” understanding the former as a “proto-argument” which consists of a set of premises offered in support of some conclusion. It is the kernel of an argument, but he considers it an argument in the full sense only if it fully engages the dialectical tier, considering alternative points of view, addressing objections to the conclusion it proposes. 