Sept. 24, 2013
Attempts to answer Gettier: causal theory, relevant alternatives
-Gettier’s counterexample is based on sufficient conditions
JTB (justified true belief)
The structure of GCEs (Gettier’s Counter Examples):
i. S justifiably believes P
ii. - P (P is false) (So S justifiably believes a false premise).
Assumption: internal justification fallible
iii. (P Q) – P is sufficient for Q, but not necessary for P
iv. Q (happens to be true, ‘luckily’ i.e. not in virtue of following from P; recall: iii
does not say P is necessary for Q; something else may produce Q while P is
v. S (validly) infers Q from P
vi. S justifiably believes Q and Q is true, but S does not know Q
1. How to cook up a GCE in 3 easy steps:
1.1 - Take an ordinarily justified belief say on basis of ordinary perception, normally
reliable testimony, general background knowledge.
1.2 - Invent circumstances in which the ordinary justification this time fails: trick,
deception, optical illusion, usually reliable sources is lying or mistaken, etc. (Zagzebski’s
1.3 - Note: S now has false belief. Do NOT serve this up as a CGE or your dinner guests
will choke. Further preparation, treat this false belief as a lemma, and invent an
inference from it to something that happens to be true (Zagzebski’s 2 accident).
Note: Easiest (and most banal) way to do 1.3 is Gettier’s own: law of addition: Disjoin
statement that turns out true by chance to the false belief of 1.2. This is a GCE with a
false lemma. Trickier exercise: make a Feldman-style GCE with no false lemma.
Homework: come up with a Gettier example EXAMPLE: I believe there is a deer in the field. But what I take to be a deer is in fact a
tree. However, my belief is valid because there is a deer in the field, but I don’t see it
because it’s behind the tree. Therefore JTB is justified but it does not constitute
What appears to be a window is really a TV screen relaying recorded images of the outside from
a week ago. You look, and form the justified belief: ‘It is raining’. As a matter of fact this is also
2. Replies to Gettier generally take one of two forms:
2.1 – Adding 4 condition to JTB