True belief and epistemic luck › Case II: the Ford and Barcelona

The second case makes the logical structure more visible. Smith has strong evidence that Jones owns a Ford. Jones's history of owning Fords and his recent offer of a ride while driving one support the belief. Smith also has a friend, Brown, whose location is unknown to him.

Smith takes the claim about Jones and constructs several alternatives by adding an "or" clause about Brown. The relevant one says that Jones owns a Ford or Brown is in Barcelona. The "or" is inclusive: at least one side must be true, and both may be. If Jones owns a Ford, the disjunction follows regardless of Brown's location.

Smith recognizes the entailment and accepts the disjunction. In Gettier's setup, however, Jones is driving a rented car and does not own a Ford. By coincidence Brown is in Barcelona. The first side is false, the second true, so the disjunction is true. Smith's evidence supported the first side, and he has no information establishing the second. Gettier, pp.122–123, Case II.

There is no requirement that Smith have evidence for both sides before a disjunction can be justified. Good evidence that a parcel is in the hall can justify believing that it is in the hall or in the kitchen. That is why the inference principle matters. Rejecting Smith's reasoning simply because he knows nothing about Barcelona would miss the logical move Gettier is using.

Gettier again judges that Smith lacks knowledge of the true disjunction. The fact that saves its truth plays no role in his evidence. The example separates the subject's justified route to belief from the actual state of affairs that makes the resulting proposition true. It reaches the same philosophical pressure point as the job case with a different logical form.