It is not vulnerable simply because Gettier cases are only true due to an element of luck. For example, one specific case of Gettier that explains this is the “Fake Barn Country” example we discussed in class. This example concerns a man walking through barn country. Barn Country is really just a facade of fake barns, but with one real barn throughout the land. The man stops right in front of the only real barn in the entire country. Because he sees a real barn in front of him, he thinks the whole country is made up of real barns. The man arriving at the one true barn is entirely by chance, and the knowledge that the land of barns is real is also by chance. This element of luck, again, makes the belief true, but does not satisfy Zagzebski's definition.