§ The justificationist view of disagreement. According to “j” view at low degrees of justified confidence [jc] our peer belief should receive similar weight, and at high levels of justified confidence we must dismiss his belief. Finally, in between levels of confidence peers credence should be consider consequently. (In a nutshell: starting from and equal weight at low levels of jc, we lower the weight of our peer belief as we raise our confidence in our own belief.)
§ Merits of the j view. This view is able to account for our intuitions in paradigmatic cases like: “mental math” and “careful checking” or “simple math”). In contrast, conformist and non-conformist failed to accommodated, at least, one of these cases.
§ No peer argument (or consequences of the long run). Sosa and Feldman are epistemic peers regarding epistemology. But Sosa, disagrees with Feldman in p, p’, p’’, p’’’,p’’’; being “p” different propositions about epistemology. Let´s assume Sosa has medium level of justified confidence in these propositions, after all he has thoroughly analyzed arguments for and against each of them and he is a well trained philosopher. (In fact, Sosa thinks we can rationally hold a high degree of confidence in our philosophical theories). According to the “j” view he can give more weight to his believe in each of the propositions involved. But if this is so, in which sense we can said they are still peers?
§ Objection I. Sosa may have a reason for overweighting his belief in all the disagreements. In this case he can still consider Feldman to be his peer. For example, Sosa may think evidence from testimony is too weak in order to receive the same weight as “material evidence”; in this case he is justified in overweighting his belief and still considers Feldman to be his peer. So at most, the argument has shown that either or the j viewer offers a motivation for his account, beyond the possibility of accounting for our intuitions, or either the idea of peerhood should be neglected.
§ Reply. It’s is worth mentioning that not any reason will succeed in replying the “no-peer argument”. There at least to conditions that must be fulfilled 1) the reason must be compatible with the “j view” 2) the reasons should be independent of agent reliability considerations. The first one is pretty obvious, and is not satisfied by the example of “material evidence” since in that case the agent should overweight his credence at all levels of jc, against the recommendations of the “j view”. More to the point, the independence requirement comes from the fact that if agents are peers any appealing to reliability is out of place: in the end both agents are equal reliable ex hypothesis, and both agents are aware of this fact. Of course, reliability considerations can be cited is some instances but they run against the idea of peerhood if they motivated every overweight of the agent beliefs. In other words, equal R means agent will get similar ratio of wrong/true beliefs but doesn’t imply than in a particular instance they must have the same result. But when the number of instance grows the ratio should converge. If at the end one of the agents has favor his credence much more often, then peerhood is being neglected.
§ Reply… (Continued). In this paragraph I will try to show that no reason can satisfy 1 and 2 simultaneously. One salient feature of Lackey’s theory was mentioned before: starting from and equal weight at low levels of jc, we lower the weight of our peer belief as we raise our confidence in our own belief. Why? A reason may come from the fact that our level of justified confidence is a reliable indicator of the chance of having a true belief. So, given that one of the agents must be wrong and the fact just mentioned it seems reasonable to reduce our peer weight as our confidence increase. Now, this reason makes use of the agent reliability violating condition 2. Even a better motivation will go along these lines: we are aware of our increase reliability as our jc grows but we have no access to our peer jc. This seems wrong for many reasons, most likely the grounds we have for our level of confidence are share by our peer, and if grounds are different then our overweighting would run against the independence principle (see Christensen 2011). Last, but not least, further information on hand is our peer equal reliability. This undermines the possibility of always appealing to our information “surplus” in case of disagreement, since at some level we must acknowledge that we are assuming a ratio of true/false belief higher than that from our peer.
On most papers peerhood assumes that: 1) both agents are equally acquaintance with the evidence, 2) are equals in epistemic virtues such as intelligence, freedom of biased, etc. This is not the same as assuming equal reliability but is easily implied. Epistemic virtues should increase the probability of acquiring true beliefs, so sharing these virtues implies sharing the propensity to obtain true beliefs, which is pretty much the definition of reliability.