  We formulate discussion graph semantics of first-order logic with equality
for reasoning about discussion and argumentation as naturally as we would
reason about sentences. While there are a few existing proposals to use a
formal logic for reasoning about argumentation, they are constructed bottom-up
and specialised to the argumentation model by Dung. There is indeed a
conspicuous lack of a formal reasoning framework for handling general
discussion and argumentation models. We achieve the generality through a
top-down formulation of the semantics of first-order logic (with equality)
formulas, addressing the current shortage.
