Context is essential in virtually all human activities. Yet some logical notions
seem to be context-free. For example, the nature of the universal quantifier, the
very meaning of “all”, seems to be independent of the context. At the same
time, there are many quantifier expressions, and some are context-independent,
while others are not. Similarly, purely logical consequence seems to be
context-independent. Yet often we encounter strong inferences, good enough
for practical purposes, but not valid. The two types of examples suggest a
general problem: how to characterise the context-free logical concepts in their
natural environment, that is, in the field of their context-dependent associates.
A general Thesis on Quantifiers is formulated: among all quantifiers, the
context-free ones are just those definable by the universal quantifier. The issue
of inferences is treated following the approach introduced by Richard L.
Epstein: valid ones are an extreme case, the result of the disappearance of
context-dependence. This idea can be applied to an analysis of a form of
abduction, called “reductive inference” in Polish literature on logic. A tentative
Thesis on Inferences identifies the validity of a strong inference that is context-independent.