  We propose a formal treatment of scenarios in the context of a dialectical
argumentation formalism for qualitative reasoning about uncertain propositions.
Our formalism extends prior work in which arguments for and against uncertain
propositions were presented and compared in interaction spaces called Agoras.
We now define the notion of a scenario in this framework and use it to define a
set of qualitative uncertainty labels for propositions across a collection of
scenarios. This work is intended to lead to a formal theory of scenarios and
scenario analysis.
