  From daily discussions to marketing ads to political statements, information
manipulation is rife. It is increasingly more important that we have the right
set of tools to defend ourselves from manipulative rhetoric, or fallacies.
Suitable techniques to automatically identify fallacies are being investigated
in natural language processing research. However, a fallacy in one context may
not be a fallacy in another context, so there is also a need to explain how and
why it has come to be judged a fallacy. For the explainable fallacy
identification, we present a novel approach to characterising fallacies through
formal constraints, as a viable alternative to more traditional fallacy
classifications by informal criteria. To achieve this objective, we introduce a
novel context-aware argumentation model, the theme aspect argumentation model,
which can do both: the modelling of a given argumentation as it is expressed
(rhetorical modelling); and a deeper semantic analysis of the rhetorical
argumentation model. By identifying fallacies with formal constraints, it
becomes possible to tell whether a fallacy lurks in the modelled rhetoric with
a formal rigour. We present core formal constraints for the theme aspect
argumentation model and then more formal constraints that improve its fallacy
identification capability. We show and prove the consequences of these formal
constraints. We then analyse the computational complexities of deciding the
satisfiability of the constraints.
