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Glances Ahead: More to Think About
II. Philosophical Analysis
A philosophical analysis of
a concept is a collection of conditions that are individually necessary
and jointly sufficient for the application of that concept. The
biconditional (phrased as “if and only if” and having truth
conditions satisfied if both parts being tested have identical truth values)
can be used in this process, and philosophical analysis is a common technique
used to simplify the determination of truth values for a biconditional
with numerous characterizing consequents. One straightforward example
of philosophical analysis would be (in which S is an agent):
Ex. S is a bachelor if and only if
(a) S is a man, and
(b)
S is unmarried.
In this case, upon examination of
the two consequents supplied, we find that, alone, each is a necessary
condition for being a bachelor—that is, S cannot be a bachelor without
being (a) a man and, separately, (b) unmarried. In combination,
the consequents are sufficient conditions for the antecedent—that
is, if S is a man and S is unmarried, then S must be a bachelor (for those
two conditions are satisfactory in defining the notion of a bachelor).
A more famous and debated example
of the technique of philosophical analysis is the following.
Ex.
S knows that p if and only if
(a) S believes that p.
(b)
p (is true).
(c) S has good reason to believe p (S is justified
in believing p).
The claim was that these conditions
were individually necessary and jointly sufficient for “S knows
that p.” However, this example was challenged by Edmund Gettier,
then reformulated by Fred Dretske and Robert Nozick, and then challenged
again by Saul Kripke.
I. Introduction to Symbolic Logic: Using Truth Tables