Irish Epistemology

My great grandpappy hailed from county Donegal, and with Saint Patrick's day at hand I thought it well to reflect on the role of luck in epistemology. It is very common for epistemologists to describe Gettier cases as cases of epistemic luck. This plays nicely into a creditible true belief theory of knowledge since accidentality is credit-undermining. However, I assert that accidentality is an accidental feature of Gettier cases. It's a by-product of constructing cases where a justified true belief essentially depends on a falsehood.

Note first that Duncan Pritchard points out in _Epistemic Luck_ that not *all* luck is knowledge-undermining: luck in having the evidence I do, for example, does not undermine the epistemic status of true beliefs properly based on that evidence.

Next, think about just what one is looking for when one attempts to put together a Gettier case. They are counter-examples to the theory that knowledge is justified true belief. So what one wants is a justified true belief which is not at item of knowledge. But truth is the aim of belief and evidence is what points to the truth in some way, so to have a justified true belief is a sort of at least partial success, yet by an extraordinary means.

The belief is on target--truth--but the ordinary means--the evidence--isn't playing the role it's supposed to play. It does point to the truth of the belief but via a sort of deviant chain. Seeing something that looks like a sheep is evidence that there's a sheep, but one's evidence is malfunctioning in some way for the thing that gives the appearance of the sheep is in fact a sheep dog. The evidence isn't hooked up to the true belief in the right way, the latter essentially depends on a falsehood.

Advocates of the falsehood view have been subject to criticism in part because they haven't spelled out the notion of essential dependence on a falsehood. I aim to correct that.

As a formal account consider

(ED) S's inference from premises P to conclusion C essentially depends on falsehood F iff (i) S infers C from P, and (ii) it is not possibly the case that [(a) S infers C from P and (b) C is justified for S and (c) either suspension of judgement or disbelief is the attitude to F which fits S's evidence].

or maybe

(ED') Conclusion C's being justified for S essentially depends on falsehood F iff (i) C is justified for S and (ii) ~<>(S's evidence remains the same with the sole exception of learning that F is false & C remains justified for S)

To see that this is an account of dependence just syntactically convert the principles into entailments (I just think they're easier to grasp as noncompossibility claims): essentially the idea is that S's learning that F is false would rob S of justification for C (even when S never considered whether F in coming to believe that C).