Reasoning depends on a reasoner's knowledge and beliefs. Yet, in real world domains, what is known or believed is often incomplete, inconsistent, or otherwise uncertain. We call such domains "weak theory domains".

We explore the use of argumentation as a basis for reasoning in weak theory domains. Argumentation is a method for locating, highlighting, and organizing relevant information in support of and counter to a plausible claim. This information can then serve as a vehicle for comparing the merits of competing claims.

We present aspects of our preliminary investigation of a formal theory of argumentation: (i) identifying a formal theory of argumentation; (ii) implementing the theory in a computer program; (iii) gathering example problems and associated arguments; and (iv) evaluating the theory with respect to the example arguments.

Current work concentrates on the structure and generation of independent, supporting arguments for an input claim and its negation. Future work will focus on argumentation as a series of adversarial moves that support and counter an input claim.