Sequential Thresholds: Context Sensitive Default Extensions
  Default logic encounters some conceptual difficulties in representing common
sense reasoning tasks. We argue that we should not try to formulate modular
default rules that are presumed to work in all or most circumstances. We need
to take into account the importance of the context which is continuously
evolving during the reasoning process. Sequential thresholding is a
quantitative counterpart of default logic which makes explicit the role context
plays in the construction of a non-monotonic extension. We present a semantic
characterization of generic non-monotonic reasoning, as well as the
instantiations pertaining to default logic and sequential thresholding. This
provides a link between the two mechanisms as well as a way to integrate the
two that can be beneficial to both.
