(fetzer)wrn

When is Reasoning Nonmonotonic?
by Terry L. Rankin

Deduction and Induction, p 290
[Fetzer] ``[A]ny deductive argument is characterized as being *valid* just
in case (a) its conclusion could not be false if all its premises were true;
(b) its conclusion contains no more content than is already provided in its
premises; and (c) the addition of further premises can neither strengthen
nor weaken this argument, which is already maximally strong''.
[(a) demonstrative (b) nonampliative (c) additive]
[A]n inductive argument will be *proper* only if (a') its conclusion could
be false even though all its premises were true, (b') its conclusion
contains more content than is provided in its premises, and [or!!!] (c') the
addition of further premises could either strengthen or weaken this argument.
[``knowledge-extending'' (a') nondemonstrative (b') ampliative (c')
nonadditive. Necessary, non sufficient conditions]

Monotonicity and Nonmonotonicity
Formal Systems
Specificity and Nonmonotonicity