Epistemology/Adding an extra condition

In the previous chapter, we saw that Gettier cases provide motivation for the idea that justified, true belief is an insufficient analysis for knowledge. In this chapter, we will consider the possibility that the tripartite analysis does not provide the sufficient conditions for knowledge because it is missing a necessary condition. In other words, we will consider whether adding an extra condition on top of justification, truth and belief will rule out Gettier cases as knowledge.

No false lemmas
A natural first thought for a new condition to add to the tripartite analysis might be to rule out beliefs inferred from false premises. A proponent of this view could then argue that Gettier's examples do not count as knowledge because the justified, true beliefs in these examples were inferred from falsehoods and so were not properly formed to count as knowledge. As can be seen from the table above, the "no false lemmas" analysis rules out the original Gettier cases provided in Gettier's famous paper. However, there have been Gettier cases that have been provided for the "no false lemmas" analysis. For example, consider the following "fake barn county" example:


 * Jones is driving through fake barn county
 * In fake barn county, it is tradition for the locals set up many cardboard cut-outs of barns
 * Jones sees a lot of fake barns thinking that they’re real barns
 * Then, Jones happens to see a real barn!
 * Jones has justified true belief that there is a barn

In this example, Jones has a justified true belief that there is a barn. But not only does he have a justified true belief that there is a barn, he has a justified true belief that is not inferred from any falsehoods. This is because Jones' belief that there is a barn is inferred directly from his visual perception of a barn and so is not inferred from any premises at all. However, Jones could very easily have been looking at a fake barn with the exact same visual justification and his belief would have been false. Therefore, even with the "no false lemmas" condition, there can still be epistemic luck.

Sensitivity conditions
Another way we could rule out the Gettier cases as counting as knowledge is by considering their relationship to the truth. The key insight behind adding a sensitivity condition is that knowledge should not only be true, but it should also track the truth. To fix the tripartite analysis, then, we just need to add a sensitivity condition that ensures knowledge must be sensitive to the truth (as shown in the table below). A proponent of this view could argue that we can rule out Gettier's examples as cases of knowledge because the justified, true beliefs in these examples are insensitive to the truth. Adding a sensitivity condition, like a "no false lemmas" condition, rules out Gettier's original examples. However, can it also rule out the fake barn county counterexample? Initially we might think that it can. After all, if the barn was not there for Jones to see, he wouldn't believe that there was a barn there. However, what if inside the real barn had been a cardboard cut-out of a barn set up. Then, if there was no barn there for Jones to see, he would have still believed there was a barn there because he would have seen a fake barn and mistaken it for a real barn. Saul Kripke takes this example one step further to show how counterintuitive a sensitivity condition could be. Consider the following case:


 * Jones is driving through fake barn county
 * In fake barn county, it is tradition for the locals set up many cardboard cut-outs of barns
 * Cardboard cut-out barns are always green in fake barn county and real barns are always red
 * Jones happens to see a real barn (with a cardboard cut-out barn inside)
 * Jones forms the justified true belief that there is a barn
 * Jones also forms the justified true belief that there is a red barn
 * If there had been no real barn there, Jones would still believe there is a barn but he would not have believed there was a red barn
 * Therefore, in this case, Jones' belief that there is a red barn is sensitive to the truth but his belief that there is a barn is not
 * Therefore, in this case, Jones knows that there is a red barn but he doesn't know that there is a barn!

A general problem with JTB+X solutions
Linda Zagzebski has argued that all analyses of knowledge which simply add an extra condition X onto the tripartite JTB analysis to acquire a JTB+X analysis will always be vulnerable to Gettier cases. This is because the fallibility of justification (as well as any added condition) will always be able to be able to be subverted to create Gettier cases. In fact, Zagzebski even provides an easy recipe with which to create a Gettier case for any JTB+X analysis of knowledge:


 * 1) Find a case of justified false belief which satisfies condition X
 * 2) Make the belief true by complete luck
 * 3) You have a Gettier case!

We will discuss Zagzebski's solution to this problem in a later chapter. However, in the next chapter, we will look to a completely new way of analysing knowledge called "reliabilism".