The Evidence Pointing Problem

Two classical arguments for uniqueness were made by Roger White which take the form of two objections to permissivism. The first is the Evidence Pointing Problem while the second is the Arbitrariness Objection. The basic idea behind the Evidence Pointing Problem is that evidential support is unidirectional.

“It cannot be that E supports P but also that it supports not-P. Whatever is evidence for P is evidence against not-P. If it could be that the evidence supports both P and not-P then apparently one could rationally hold both contradictory opinions at once. But that can’t be right.” (White 2014: 314)

Schoenfield provides an analogy with a dial. Suppose there is a dial that indicates where the total body of evidence points to, then the dial can only point in one direction. If permissivism entailed that, in at least some cases, the dial pointed in more than one direction simultaneously, then permissivism cannot be true (Schoenfield 2014: 199-200). It might seem as if a body of evidence could point in more than one direction if part of the evidence supported P and part of the evidence supported not-P. However, it would be mistaken to think that the evidence supported both P and not-P just because parts of the evidence supported one or the other. Rather, if the parts of the evidence that supported P were, together, stronger than those parts which supported not-P, then the evidence as a whole supports P. If they were weaker, then the evidence as a whole would support not-P instead. And if

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the conflicting components of the evidence were of equal strength, the evidence as a whole would neither support P nor not-P.

White also argues that evidential support relations hold necessarily (White 2014: 313). By this he means that if a body of evidence E supports a proposition P, then E necessarily supports P. He provides two arguments to support this claim. The first argument is that if evidential support relations are contingent, it would be unclear how one would be able to assess what the evidence supported (ibid: 314). The thought is that, suppose there is some body of evidence E, and there is a question of whether it supports a belief B. The only way to determine whether E supports B is, either if the support relation is necessary24 or if there is some further evidence E’, which would indicate whether E supports B. If the question of whether E supports B is neither apriori nor supported by other evidence, it is unclear how we can determine whether to believe B on the basis of E. If the question of whether E supports B depends on further evidence E’, we need to determine whether E’ supports the proposition that E supports B. This support relation, in turn must also either be necessary or depend on yet further evidence E’’. Eventually, either we run out of evidence, in which case we cannot determine whether to believe B on the basis of E, or we rely on some evidential support relation which is apriori. Hence, when assessing what one’s total evidence supports, the only way in which such an assessment is possible is if the support relation were necessary.

The second argument White offers against the contingency of evidential support is the following: If the question of whether E supports B is determined by some contingent fact, then there are things that we may do which do not change the evidence, but which nevertheless change the fact about whether E supports B. In an example raised by White on climate change, he supposes that our evidence actually supports climate change. He argues that if this support is contingent, there may be things people could do to change whether the evidence supports climate change without changing the evidence or the climate. However, White argues that this seems absurd (Ibid). Since people cannot change whether it is rational to believe a proposition based on the evidence without changing the evidence, evidential support cannot be contingent.

White’s claim that the evidential support relation is a necessary one is crucial to his argument for uniqueness. If the evidential support relation holds necessarily, and a

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Here, what White means by necessary is that true facts about whether E supports B are like mathematical and logical truths which need no further evidence and are entailed by any and even the null set of propositions.

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body of evidence cannot support both a proposition and its negation at the same time, then if the evidence, E, supports a belief B for one person, it supports B for everyone who possesses that evidence. Since E supports B for everyone who has E, B, and only B is justified for everyone given that their total body of evidence is E. This last claim just is uniqueness.

To be clear, the claim that evidential support is not contingent is controversial. Consider White’s two arguments for evidential support being necessary. White considers it unacceptable that people may not be able to assess whether their evidence supported a proposition or that people could change whether their evidence supported a proposition without changing the evidence. However, those who reject White’s necessity claim may be willing to accept these supposedly unacceptable implications. For instance, with respect to the first objection, externalists like Goldman are willing to accept that we might not be justified in believing that E supports B even when it really does (Goldman 2010: 202). On Goldman’s account, he only provides the truth conditions for when a belief is justified, not an instruction manual for how to acquire justified beliefs (Goldman 1979: 90-91). Therefore, claiming that people could not figure out what they ought to believe on the basis of their evidence, if evidential support was contingent, is not an objection to the latter claim.

With respect to the second objection, a reliabilist like Goldman could also accept that there are some circumstances in which we could change whether the evidence supports our belief without changing the evidence. Consider the following case:

Seeing Red: Normally, when an object appears red to John, it actually is red. In world W1 John is currently looking at a red object. His evidence consists of his current experience of seeing an object that appears red to him as well as the cumulative of his previous confirmation of red-seeming objects to be in fact red. In world W2 everything is the same, except that just as John looks at the red object his prankster friend Mary without John’s knowledge shines red light on a number of white objects just outside of John’s field of vision to make them appear red.

In both W1 and W2, John has the same evidence. However, a reliabilist could plausibly claim that different beliefs are justifiable to John in W1 and W2. In W1, a reliabilist would say that John’s evidence does reliably indicate that the object that he is looking at is red. In W2, the reliabilist could deny this since inferring that an

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object is red on the basis that it appears red, and that previous red-seeming objects have turned out to be red does not reliably indicate that a given red-seeming object is in fact red. If so, then the fact that evidence supports something different in W2 is the product of Mary’s actions. Therefore, it seems that reliabilists and other externalists about justification have reason to think that evidential support is not a necessary connection.

The fact that the non-contingency of evidential support is a controversial claim is crucial, as Schoenfield’s defence of permissivism relies on the claim that evidential support is contingent. I shall discuss her account of permissivism later in this chapter. Before I do that, let me first present White’s Arbitrariness Objection to permissivism.