Richard Feldman argues for the view that given epistemic peers – people with roughly equivalent reasoning powers, intelligence, and background information – who share all of their evidence with one another and yet each come out holding different doxastic attitudes regarding a proposition cannot both be reasonable. To support this view, Feldman offers (something like) the following thesis:
The Uniqueness Thesis For any body of evidence E, there is only one proposition p such that:
(i) within a set of propositions under consideration by epistemic peers, the conjunction of p and any other member(s) of that set would be inconsistent,
(ii) p is justified by E, and
(iii) there is only one attitude toward p – belief, disbelief, or suspension of judgment – that is justified for S by that body.
To form a counterexample a scenario could be created in which a body of evidence is given but, in fact, justifies two distinct doxastic attitudes. I would like to briefly look at and evaluate such a possible counterexample.
Don’t Take the A-Train
Smith and Jones, both from out of state, arrive one morning at the Grand Central Terminal in NYC and are trying to catch the next train to the Museum of Natural History as quickly as possible. Smith is an enthusiastic science buff visiting the museum because it’s on his vacation checklist. Jones is visiting the museum because she has an interview for the position of Astronomical Exhibition Director. Neither stops to look at a map, and they coincidentally stop the same person, who is selling newspapers, and ask if the A train stops at 81rst street this time of day – to which the person hurriedly answers, in a thick New York accent, “You bet.” Smith forms the belief that the A train stops at 81rst Street this time of day. On the other hand, given the importance of her meeting, Jones suspends judgment.
One now might want to argue that both Smith and Jones are reasonable in the unique doxastic attitude they each take toward the proposition, ‘The A train will stop at 81rst Street this time of day’, given that the only evidence they have is the testimony of a native newspaper salesman. Thus, the Uniqueness Thesis is false.
Unfortunately, for the challenger of the Uniqueness Thesis, this counterexample fails in at least two respects, the second related to the first. The first is the fact that Feldman, while arguing for his position, does not include pragmatic reasons for the formation of a correct doxastic attitude, only evidential reasons. Clearly, Jones has more at stake, however, given only the testimony of the newspaper salesman, either they are both epistemically justified in believing the A train stops at 81rst Street or not. However, let us entertain the possibility that pragmatic reasons are somewhat important in this case. What more than likely follows, then, is that Smith and Jones are no longer working from the same body of evidence. For, Jones’s pragmatic reason would seem to reveal a host of possible epistemic doubts regarding the newspaper salesman’s testimony that would make incipient background information – such as memories of her prior experiences of asking hurried strangers questions and not getting reliable answers, especially in a large city such as New York and in a loud and bustling subway station – ostensibly relevant. So left at that point, the two distinct propositional attitudes in fact entail two distinct bodies of evidence: the original, retained by Smith, and a new set for Jones. This contradicts our assumption. Furthermore, if Jones were to share those doubts with Smith, the original evidence set shared between them would be aggregated with the background information, and they would, again, share the same body of evidence. Smith would then either agree, or persuade Jones that it is unreasonable not to trust the testimony of a New York native. Though, sadly for both, the A train does not stop at 81rst street during the day.
 We will assume, with respect to one who believes and one who disbelieves, that, in fact, they both cannot be right. In other words, it is either the case that p or not-p.
 Feldman, Richard (2007), ‘Reasonable Religious Disagreements,’ in L. Antony (ed.), Philosophers without God: Meditations on Atheism and the Secular Life , Oxford: Oxford University Press.
 This example is based on the train examples found in Jeremy Fantl and Matthew McGrath’s “Evidence, Pragmatics, and Justification” found in Epistemology: An Anthology, Blackwell Publishing, 2008.