been asked to imagine that only one new belief is formed as a consequence of the great reveal. But perhaps that is psychologically implausible. Wouldn't we expect subjects to form an additional belief, such as the belief that the thing on the plate looks like a tomato?30 If we have two beliefs here, couldn't the coherentist say that these two beliefs are mutually supporting? Couldn't she say that the belief that the thing is a tomato supports the belief that it looks like a tomato, and that the belief that it looks like a tomato is something that supports the belief that it is a tomato? If she said that, she could say that there is something that changes after the great reveal. Before that, she didn't have any belief that supported her belief that the thing is the tomato. After that, however, she did. She formed the beliefs that the thing is a tomato and that it looks like one concurrently, and each supports the other.
1.53 But even if the coherentists said this, it wouldn't get them out of the jam. Suppose that you were playing this game with a friend. Upon seeing the tomato, you spontaneously formed these (allegedly) mutually supporting beliefs:
1 This looks like a tomato. This is a tomato.
1.54 Your friend, let's suppose, formed these beliefs:
1 This looks like a lemon. This is a lemon.
1.55 Now, we're not supposing that your friend suffered from some sort of illusion or hallucination. They had an experience indistinguishable from yours. We're not supposing that they're confused about how tomatoes and lemons look. We're also not supposing that you've shared your answers yet. You spontaneously judge that the beliefs in (1) are correct, and your friend spontaneously judges that the beliefs in (2) are correct. It's surely possible for one's beliefs to fail to “match” one's experience and for one to fail to notice this. Suppose that such a mistake is what happened in the case of your friend's assessment of the fruit in plain view.
1.56 Yours and your friend's sets of beliefs are equally coherent. Thus, from the perspective of coherentism, there are no grounds for saying that your beliefs are better justified than your friend's beliefs. And yet it seems that there's a clear difference between your beliefs, and that your beliefs are better justified than theirs. This is a different normative difference from the one we started with, and it doesn't look like the coherentist can account for this difference.
1.57 It seems that the coherentist's fixation on the internal relations between beliefs leads them to overlook the rational significance of mental factors external to belief (e.g. relations between beliefs and experiences). Moreover, it seems that a natural story about how the beliefs in (1) are justified is one that adverts to experience. Your beliefs are justified and your friend's beliefs are not because your beliefs fit your experiences and theirs do not. This difference is not a difference in terms of how coherent your beliefs are. This factor plays no role in filling the pages of Your Book of Beliefs, but this just seems to be an indication that there's more to the explanation as to how your beliefs are justified than what's contained in that book. Perhaps we cannot really tell which of your beliefs belong to the book of Your Justified Beliefs until we know something about your experiences and how they fit with your experiences.
1.58 We didn't need perceptual beliefs to make the point. The point could have been made equally well using introspective beliefs, the beliefs you form straight off about your own mental life. And, indeed, such an introspective example is offered by Ernest Sosa, in his famous paper “The Raft and the Pyramid” (1980). Consider this passage, in which Sosa poses the following thought experiment:
Thus take my belief that I have a headache when I do have a splitting headache, and let us suppose that this does cohere within my present body of beliefs … such a belief may well have relevant relations of explanation, logic, or probability with at most a small set of other beliefs of mine at the time: say, that I am not free of headache, that I am in pain, that someone is in pain, and the like. If so, then an equally coherent alternative is not far to seek. Let everything remain constant, including the splitting headache, except for the following: replace the belief that I have a headache with the belief that I do not have a headache, the belief that I am in pain with the belief that I am not in pain, the belief that someone is in pain with the belief that someone is not in pain, and so on. I contend that my resulting hypothetical system of beliefs would cohere as fully as does my actual system of beliefs, and yet my hypothetical belief that I do not have a headache would not therefore be justified. What makes this difference concerning justification between my actual belief that I have a headache and the hypothetical belief that I am free of headache, each as coherent as the other within its own system, if not the actual splitting headache? But the headache is not itself a belief nor a relation among beliefs and is thus in no way constitutive of the internal coherence of my body of beliefs. (1980, p. 19, italics added)
1.59 Sosa's thought experiment offers reason to doubt that the justification for introspective beliefs such as that you have a headache right now derives from facts about how your beliefs are related to one another. This is all thse more reason to see why the Isolation Objection is a pressing one in light of the coherentist's claim that the only relevant difference between justified and unjustified beliefs is how well they cohere with the rest of the believer's beliefs.
1.60 The intuition that underwrites the Isolation Objection is related to another influential objection to coherentism. Some of the clearest cases of irrational belief are cases in which someone is caught in the grips of delusion or subject to brainwashing. It doesn't matter whether our example involves a cult member brainwashed into believing that billions of years ago rational beings navigated the universe in spaceships that looked very similar to the cars of the 1950s or whether our example involves someone who firmly believes that their loved ones have been replaced by impostors.31 While the beliefs of such believers seem to be paradigmatic cases of irrational belief, it doesn't seem that we can account for the irrationality of such beliefs in terms of considerations of coherence. We want to say that our beliefs are rational, theirs are not, and that it's clear that there's a significant normative difference between them, but this difference cannot be traced to something like a degree of coherence that our beliefs display that theirs lack or the presence of incoherence that their beliefs display that ours do not. Part of what's so disturbing about subjects like this, subjects we'd describe as “having lost touch with reality,” is that their beliefs are often chillingly coherent. The most salient difference between our beliefs and theirs is that our beliefs are tethered to reality because they are properly responsive to new experiences. Unfortunately for the coherentists, they cannot straightforwardly accommodate this point, as they see justification as having all to do with relations between beliefs.32
1.5 Foundationalism
1.61 The infinitists and coherentists try to account for the possibility of justified belief in terms of the rational support provided by more justified beliefs. On this view, the justification for any justified belief is derivative in the sense that it derives the necessary rational support from further justified beliefs. The coherentists and infinitists disagree about how supporting beliefs have to be structured to ensure that justified beliefs are justified, but they agree that stopping the justificatory regress doesn't involve any belief that (i) can justify further beliefs and that (ii) does not derive its justification from any further belief. These beliefs, which have been called properly basic, foundational, non‐inferentially justified, and immediately justified beliefs, are, according to the foundationalist, epistemically essential. Without them, none of our beliefs could be justified.
1.62
