The Gettier Problem
As every schoolkid who has taken 'Theory of Knowledge' knows Edmund Gettier ( http://www.ditext.com/gettier/gettier.html ) questioned the sufficiency of the 'traditional' definition of knowledge as:
Justified (J)
True (T)
Belief (B)
by giving counterexamples were 'Smith' or 'Jones' or whoever had Justified True Belief but not, intuitively, knowledge. One solution to the probem is to expand the definition of knowledge to include a degettierising "truth-tracking" condition (DG): if the proposition were not true then the subject would not believe it.
Fallibilism
Now, just about everyone (not just schoolkids taking TOE) has a pretty strong intuition that justification need not be certain. If we insisted that our justifications alone entailed truth we would have very little justification and very little knowledge indeed.
The Infallibilist position can be characterised as justification implying truth. If it is justified, then it is true; if it is not true then it is not justified. What we wish to avoid is the entailment of truth by Justification. The problem with truth-tracking is that it implies that a believed proposition can only be justified if it is certain.
Nasty Consequence (NC) : B→ ¬(J&¬T) (if it is believed then it cannot be justified and false).
Lets characterise the truth-tracker degettierising condition:
(DG) ¬T→¬B (if it is not true then it is not believed)
Does DG entail NC? We need a counterexample to:
1. (¬T→¬B) ├ B→ ¬(J&¬T) (if it is not true then it is not believed entails if it is believed then it cannot be justified and false)
A counter example would be a believed proposition that is both justified and false:
2. B & (J&¬T)
Without DG that is a piece of cake, with DG, however:
3. DG is true in two circumstances:
3.a ¬B, we do not believe the proposition
3.b T the proposition is true
Both of these conflict with 2.
And? Your Point Is?
A truth-tracking condition implies certainty in knowledge, you cannot add a truth-tracking condition to the Justified True Belief conception of knowledge and retain fallible knowledge. The DG condition requires anything that is justifed and believed to be certain. As any knowledge must be justified and believed any knowledge with DG must be certain.
Swap "reliably formed" for justification and, for the most part, we fail to solve the problem. Most conceptions of reliability include truth-tracking within their make up.
We have three choices:
1. Accept it that knowledge must be certain
2. Accept that the examples given by Gettier are examples of genuine knowledge.
3. Come up with some other solution.
Monday 7 April 2008
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3 comments:
Nobody holds that (DG) should be understood as an indicative conditional. So the argument can't be that simple. What does one have to hold about the semantics of subjunctives to get your argument to run?
I don't think I really have a concept of the semantics of subjunctives. But, at a minimum, I would expect "it would not be believed were it not true" to exclude the possibility of it being both believed and not true. That contradicts the counterexample to (NC).
I'm not sure I understand your response. The tracking condition, as Nozick and others understood it (and before we get take account of methods and such), says that if one knows that p, then in the closest bands of worlds in which p is false, one does not believe that p. I don't know if that excludes the possibility of something being believed and not-true in the sense you intend in your reply.
And I'm still not sure how we get from there to (NC). Or how I'm to understand (NC), for that matter. Is (NC) itself to be understood as an indicative, or a subjunctive? If it's an indicative then, unless I'm even more over-caffeinated than I think I am, K -> (NC) is just equivalent to factivity. No tension with fallibilism there. So I guess we should read it as a subjunctive. But in that case, surely we need some grip of the logic of subjunctive conditionals to check whether there's an entailment here.
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