Volume 17, 1992
A Nonquantitative Approach
The author describes a formal system for interpreting and generating epistemically-qualified judgments, that is, judgments qualified by phrases like “it is certain that,” “it is almost certain that,” “it is plausible that,” and “it is doubtful that.” The system has two noteworthy properties. First, the system’s qualifiers are purely qualitative. Second, the system is based on epistemic warranting conditions, not truth conditions. The first property is noteworthy because it makes the system an alternative to systems that use numerical certainty factors to interpret epistemic qualifiers; unlike these numerically-based systems, the system the author describes is faithful to the surface meanings of epistemic qualifiers. The second property is noteworthy because it makes the system an altemative to deductive systems; unlike deductive systems, the system the author describes supports nonmonotonic inferences. The author’s account includes precise warranting conditions for system-supported judgments, a semantics that fixes the meaning of system judgments, and algorithms for generating system judgments.