(J-Ext[C]) For any agent S, S’s belief that p is justified IFF it is caused in the appropriate way by the fact that p.In this post I will like to argue against this claim. I begin by distinguishing between two types of explanations of why someone might hold a certain belief—namely, causal and rational. Consider the following example:
The ‘Crazy Jack’ Counterexample:
Jack is convinced that alien creatures from a distant galaxy regularly abduct and perform bizarre experiments on him. We ask Jack’s psychiatrist why he has this belief, and the psychiatrist responds ‘because he has sush-and-such physical defect in his brain.’ There are two ways of interpreting the psychiatrist’s answer. First, we may view it as giving a causal explanation of Jack’s belief. On this interpretation, Jack need not be aware that he suffers from any such mental defect for it to count as the “reason” for his having the belief he has. It is simply a fact about jack that his belief is so caused. Alternatively, we could interpret the psychiatrist as giving Jack’s own reason for believing that he has been subjected to alien experimentation. Perhaps Jack has learned that he has a brain defect, and he takes it to be evidence that aliens have been tampering with his body. In that case, the psychiatrist’s explanation would actually be Jack’s reason for believing what he does.
Most J-externalists view justification along the lines of the first explanation. More specifically, J-externalists typically maintain that a belief is only justified if it is causally connected, in the right sort of way, to the state of affairs that makes it true. By contrast, the J-internalist insists that it is reasons, not causes, which are necessary for justification. More specifically, the J-internalist rejects the idea that the causal aetiology of a belief determines its epistemic standing. By her lights, this would be to confuse reasons and causes. Admittedly, there is some ambiguity in the term 'reasoning' itself. On the one hand, it may indicate a logical argument that, if valid, supports the truth of a belief. On the other hand, it may refer to the process of drawing a conclusion from premises. The J-internalist maintains that it is not the process but the validity that is epistemically relevant. We reason from our evaluation system to defend what we accept, and this has a causal explanation. Nonetheless, the validity of the reasoning is not to be explained causally but in terms of the inferential relation between the premises and what is concluded.
As the “crazy Jack” example illustrates, one and the same thing—namely, the physical defect in Jack’s brain—might be both the cause and evidential basis of Jack’s belief. Thus, the J-externalist points out that the mere fact that something is a causal explanation of why you believe what you do, does not entail that it cannot also be the reason for your belief. For example, in Alvin Goldman's causal account of knowledge, while it is ventured that “inference is a causal process”, all that seems to be meant by this is that, “if a chain of inferences is ‘added’ to a causal chain, then the entire chain is causal”. The J-externalist need not deny that validity cannot be explained causally. What he may claim is that when a belief is produced appropriately, the causal process by which it is produced just is the relation of evidential support. In that case, the J-internalist’s task is to show that the relation of evidential support is really distinct from whatever causal process produces a belief.
One way this may be done is by describing a case where a subject’s reasons justify her belief, even though they have no causal influence1 on the formation and acceptance of the belief. The following example seems to fit the bill:
The ‘Fanatical Tom’ Counterexample:
Tom is a member of a religious cult that teaches that the director of the National Security Agency, Keith Alexander, is the anti-Christ. Based on this teaching, Tom comes to believe that the NSA is engaged in the illegal warrantless surveillance of US citizens. Let us assume for the sake of argument that Tom’s beliefs lack any credible evidence. However, it just so happens that the NSA really is illegally spying on US citizens. Although Tom’s belief is true, we would still deny that he has knowledge. Similarly, we would regard his belief as unjustified. In short, Tom has a true belief, but not a justified one. Now let us suppose further that Tom is determined to convert his neighbour, Fred, who is very sceptical about Tom’s claims. Tom sets out to find evidence that would convince Fred by taking apart every electronic appliance in Fred’s home. In the process, Tom discovers a mini camera in Fred’s smoke detector and a small microphone in his telephone receiver, both with NSA serial numbers. Given this newly acquired evidence we would now hold that Tom’s belief is justified and may even constitute knowledge. However, since Tom believed that the NSA was engaged in illegal surveillance even before he discovered the spyware, his belief was clearly not caused by this evidence. To wit, if Tom hadn’t discovered the spyware, he still would have the belief in question. Now the question that confronts us is this: is the questionable causal aetiology of Tom’s belief sufficient to denying that it is justified once he has acquired the new evidence? Intuitively, the answer seems to be no. We would regard Tom’s belief as justified despite its untoward causal origins. Therefore, it seems that it is the evidence one has for a belief, rather than its causal aetiology, that determines whether or not it is justified.
Perhaps the unpropitious consequences of the ‘fanatical Tom’ counterexample might be avoided by weakening the J-externalist causal requirement. For example, Goldman and others2 have suggested that a belief need not have its ‘causal origin’ in a reliable process, but only that it be ‘causally sustained’ by such a process. On this more moderate view, Tom’s belief can be seen as ‘causally sustained’ by the discovery of the spyware in the sense that if Tom were to give up his fanatical religious views, he would still continue to believe that the NSA is spying on US citizens. While it may be true that beliefs are generally ‘causally sustained’ by their evidence in this way, this need not be the case. For example, the ‘fanatical Tom’ counterexample can be adjusted so that Tom’s belief would not be ‘causally sustained’ by the spyware evidence. We may suppose that if Tom were to lose his religious conviction this would cause his entire world-view to collapse, to the extant that he would lose all his other beliefs. However, this fact does not seem to affect our intuition that Tom’s belief is justified. Thus, even the weaker requirement that a belief be ‘causally sustained’ by a reliable process does not appear to be a necessary condition for justification.3
1 This argumentative strategy can be broadened to apply to other nomonological J-externalist accounts by substituting “causal aetiology” with “history of the belief” [see: Lehrer 1990, ch. 8]. The "Fanatical Tom" counterexample represents what is known as a Gypsy-Lawyer type scenario.
2 Gilbert Harmon [1970, 1973, 1986] and Marshall Swain  have argued that a belief is only based on evidence if the evidence conditionally or partially explains the belief.
3 For an argument that no revision of Swain’s account can succeed, see Kvanvig 1985.
Goldman, A., (1967) "A Causal Theory of Knowing," Journal of Philosophy 64 (widely reprinted).
Harman, G., (1970) ‘Knowledge, Reasons, and Causes’, Journal of Philosophy 67: 844-55
Harman, G. (1973) Thought. Princeton, NJ: Princeton University Press.
Harman, G. (1986) Change in View. Cambridge, MA: MIT Press.
Kvanvig, J. (1985) ‘Swain on the Basing Relation’, Analysis 45: 153-58.
Swain, M. (1981) Reason and Knowledge. Ithaca, NY: Cornell University Press.