Wednesday 28 March 2007

Causal vs. Rational Explanations (Part 2)

In my previous post on this topic, I briefly touched on a common reply to Lehrer’s Gypsy-Lawyer type cases—namely, the suggestion that a belief need not have its ‘causal origin’ in a reliable process, so long as it is ‘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’ (henceforth ‘SPY’).

In this post I will examine one way of unpacking the concept of what it means for a belief to be causally sustained by some bit of evidence (whether propositionally or non-propositionally understood)—namely, Marshall Swain’s notion of a counterfactual cause. We may define a counterfactual in terms of possible world semantics. Following Lewis let us say that the truth of the statement A > B consists in the fact that, among possible worlds where A holds, there is at least one world where B holds and which is more similar to our world than any world where A holds but B does not. (For the sake of simplicity, I will just speak in terms of the closest possible world.)

Roughly, the idea is that a belief, B, is based on a reason, R, if R is either the non-deviant cause or counterfactual cause of B. R counterfactually causes B if in the closest possible world where the actual cause, C, is missing, R causes B. Thus, causal theorists maintain that the underlying intuition behind the causal theory can be preserved by insisting that if the justifying evidence does not actually cause belief, it must counterfactually cause belief. Applied to the ‘Fanatical Tom’ counterexample, we may say that in closest possible world in which Tom’s belief that SPY is not caused by his fanatical religious views, it is caused by the spyware evidence. Thus, the spyware evidence is the counterfactual cause of Tom’s belief.

We may add one important restriction to the idea of a counterfactual cause. First, it is crucially important that we limit ourselves the closest possible world. Otherwise, the notion of a counterfactual cause would become much too broad; allowing beliefs to be based on reasons when it is obvious that they are not so based in the actual world. (Presumably, it is such considerations that prompt Swain to limit the application of the concept of a counterfactual cause to the reason next in line to the reason that actually causes the belief.) Thus, Swain’s view may be put as follows:
S1: Subject S bases her belief that p on R IFF S’s having R is either (i) a cause of S’s believing that p in the actual world, or (ii) S’s having R is a counterfactual cause, such that R causes S’s believing that p in the closest possible world in which the actual cause, C, is absent.
If we accept the restriction on what constitutes a counterfactual cause imposed by S1, we seem able to adjust the ‘Fanatical Tom’ counterexample so that the spyware is no longer the counterfactual cause of Tom’s belief. For example, we could imagine that Tom is not only a religious fanatic, but that he is also a member and ardent believer in a webring devoted to conspiracy theories. Thus, holding all other parts of the ‘Fanatical Tom’ counterexample constant, we may stipulate that in addition to his fanatical religious views, he has also read about the NSA’s surveillance activities on the internet, before actually discovering the spyware evidence in Fred’s home. On this revised version of ‘Fanatical Tom’ case the closest possible world in which Tom’s belief is not based on his religious views, it would actually be based on his reading the conspiracy theory webring. Thus, according to S1, the spyware no longer constitutes a counterfactual cause for Tom’s believing that SPY. Since in the re-described case, Tom’s belief seems no less justified than it is the original case, the introduction of counterfactual causes fails to resolve the present difficulty.

But perhaps Swain is being unnecessarily conservative when he restricts the notion of a counterfactual cause to the closest possible world. Perhaps it would be sufficient to restrict ourselves to nearby worlds in which Tom both finds the spyware and believes SPY. On the present proposal, we might be able to rescue Swain’s theory by widening the scope of what counts as counterfactual cause to all worlds sufficiently close to the actual world. Thus modified, Swain’s counterfactual cause may be summarised thus:
S2: Subject S bases her belief that p on R IFF S’s having R is either (i) a cause of S’s believing that p in the actual world, or (ii) for some set, C, of possible counterfactual causes of S’s belief that p, R is a member of C.
On S2, R need not be the next in line to the actual cause, C, such that in the closest possible world in which C is not the actual cause R causes S’s belief that p. It is sufficient that R be the cause of S’s belief that p in some nearby world. As with most talk of nearby worlds, there is an obvious difficulty regarding how one delineates which worlds count as nearby and which do not. Or, to put the problem differently, how do we determine (in a non-arbitrary manner) which reasons, out of the maximal set of possible reasons, ought to qualify as counterfactual reasons.

One plausible criterion would be to restrict ourselves to reasons that are occurrent to the subject in the actual world. Thus, we may add to S2 the clause that for some possible reason, R, to be included in the set, C, of possible counterfactual causes, it must be occurrent to S in the actual world. Assuming that this provides a plausible and sufficient restriction on which worlds ought to count as nearby, we seem to have a working definition of a counterfactual cause. S2 provides us with a reply to the ‘Fanatical Tom’ example since it allows both the conspiracy webring and the spyware (along with any other potential reasons occurrent to Tom in the actual world) to be considered a counterfactual cause of his belief.

Unfortunately, this still is not sufficient for rescuing the notion of a counterfactual cause. An even more decisive objection to the Swainesque reply to the ‘Fanatical Tom’ problem is that it allows the spyware to be the counterfactual cause of Tom’s belief even when it seems obvious that it is not justified. For example, suppose that Tom’s religion teaches him to reject all evidential relations and that only beliefs based upon ‘faith’ are justified. However, Tom realises that his neighbour, Fred, still buys into ‘the whole evidence thing’ and appeals to the spyware solely for the purpose of converting Fred. The idea is that Tom does not see the spyware as genuine evidence himself. In such a case, Tom’s belief would clearly be unjustified. However, in such a scenario, the spyware would still be the counterfactual cause of Tom’s belief by Swain’s lights. In the closest possible world in which Tom no longer has his religious beliefs, and in which he still believed SPY, his belief would be based on the spyware. This is because in that world, the religious belief would no longer prevent Tom from recognising the spyware as a reason for believing SPY. Thus, Swain’s notion of a counterfactual cause allows the spyware to causally sustain a belief even when it is clear that the belief is not justified.

I believe the above analysis suggests that all attempts to cash out the idea of a belief being causally sustained by evidence in terms of counterfactual causation is moribund. In my next post on this topic I will present what I believe is a successful reply to Lehrer Gypsy-Lawyer type scenarios.

Tuesday 20 March 2007

McDowell’s Direct Realist Reply to Scepticism

McDowell’s claim that in veridical cases of perception objects are “immediately present to the mind” has earned him the title of direct realist. Direct realism is the thesis that what we perceive are not merely appearances (insert: sense data, veil or ideas or whatever else suits your fancy) but rather objects themselves.

Direct realism can be used against arguments for external world scepticism (EWS) of of the following form:
P1: Our EW beliefs are based on sense data beliefs
P2: Sense data beliefs cannot justify EW beliefs
EWS: Our EW beliefs are not justified
The direct realist resists EWS by rejecting P1. There are two senses in which the direct realist can maintain that our EW beliefs are not based on sense data beliefs. First, they can deny that there are such things as sense data beliefs. This is certainly true in McDowell’s case since his rejection of the highest common factor view, a fortiori, includes the eschewal of any such mediating beliefs. Second, if we interpret the locution ‘based on’ in a strong inferential sense, then a direct realist may insist that our EW beliefs are not inferred from any other beliefs at all but are rather immediately grasped by the perceiving subject.

However, the locution ‘based on’ need not be taken in this strong inferential sense. A sceptic may insist that there can be a weak sense of ‘based on’ that is non-inferential. For example, we may interpret the phrase ‘based on’ in causal terms. Putatively, it seems undeniable that our EW beliefs are causally based on appearances or sense impressions. According to an empirical-psychological account of vision, the act of seeing an object involves several complex physiological processes. Moreover, we never see objects themselves, but merely the light bundles reflected off an object. Thus, there are several causal intermediaries between our EW beliefs and the objects in the eternal world. Thus, our sceptical argument may be reformulated as follows:
P1*: Our EW beliefs are (causally) based on sensory appearances
P2*: Sensory appearances cannot justify EW beliefs
EWS: Our EW beliefs are not justified
Significantly, P1* does not assert that sensory appearances are the intentional object of our perceptual experience. For instance, by P1*’s lights we are free to view sensory appearances as the means rather than object of our perceptions. In other words, P1* merely asserts that sensory appearances form part of the causal chain linking our beliefs to the EW that gives rise to our beliefs. Thus, P1* can be construed along purely direct realist lines—to wit, we may hold P1* while simultaneously maintaining that objects themselves (and not some mental intermediary) are the intentional objects of our perceptions. Thus, even if we grant direct realism’s denial of an inferential intermediary, P1* still stands.

Unfortunately for the sceptic, this reply fails in the case of McDowellian direct realism. McDowell may gladly concede that the causal descriptions (with all its various intermediary steps) of empirical psychology are true. However, McDowell maintains that the empirical-psychological account is not only one available. In fact, McDowell draws on the Sellarsian idea of there being a sui generis “space of reasons” for precisely this reason. When McDowell describes perception as being direct, he is speaking in terms of the logical space of reasons, not in terms of the logical space in which the subject matter of empirical science falls. Things like photons or electrical impulses are  not of the right sort to act as a reason for one's beliefs. Trading on this ambiguity in the locution ‘based on’, McDowell may accept P1*, but point out that P1* cannot plausibly be combined with P2* in order to generate EWS.  P1* (explicitly) exploits the epistemically insignificant notion of being ‘causally’ based on, while P2* (implicitly) exploits the  epistemically significant notion of being ‘justificationally’ based on.  This equivocation in the explicit notion of "based on" in P1* and the implicit notion of "based on" in P2* prevents the inference from going through.

In sum, McDowellian direct realism is effective against sceptical arguments of a certain form. Specifically, sceptical arguments that ride on there being an inferential or causal intermediary between our EW beliefs and the objects we perceive are easily defeated by direct realist considerations. Of course,  arguments for EWS may take other forms as well.

Saturday 17 March 2007

My Raasay Weekend, to the Tune of Robert Service

There's A race of men that don't fit in,
A race that can't stay still;

So they break the hearts of kith and kin,
And they roam the world at will.

They range the field and they rove the flood,
And they climb the mountain's crest;

Theirs is the curse of the gypsy blood,
And they don't know how to rest.

If they just went straight they might go far,
They are strong and brave and true;

But they're always tired of the things that are,
And they want the strange and new.

Thursday 8 March 2007

Gettierising Nozick

Over at The Web of Belief, I lay out a Gettier case against local reliabilism (which is itself based on an earlier post of mine, Undescriminating Reliabilism). Let's call my proposed Gettier case against local reliabilism GLR. The version of local reliability I took as my target was admittedly quite simple, so here I will attempt to apply GLR to a much more sophisticated version of local reliability—namely, Nozick’s counterfactual account. Nozick [1981, p. 179] argues that the true belief that p is knowledge only if:
(N1) If p were true, then S would believe that p
(N2) If p were not true, then S would not believe that p1
Following David Lewis [1973] we may say that (N1) and (N2) are true, as counterfactual statements, iff in possible worlds near to the actual world, if p is true, S believes that p, and if p is false S does not believe that p. Nozick recommends that we assess (N1) and (N2) by reference to what is the case in all nearby possible worlds. Roughly, a world may be described as ‘nearby’ if it is only slightly different from the actual world and ‘distant’ if it is radically different.

The following reply to GLR seems available to Nozick. Let us suppose that the set of nearby possible worlds include ones in which the computer is running a different program or is missing altogether. In such nearby worlds, although there is a red cube in the box, there is no hologram of a red cube. Since in such a world the subject would not believe that (a) although (a) is true, (N1) has not been satisfied.

One initial difficulty with this reply is that it is not immediately clear that worlds in which the computer is running a different program or is missing altogether should be considered nearby. But let us, for the sake of argument, assume that such worlds are in fact nearby.

Even so, Nozick’s strategy for responding to GLR proves too much, since it also impugns cases in which the subject intuitively has knowledge.

The ‘Jesse James’ Counterexample:
Consider the case of the Jesse James Bank Robbery, as described by Craig [1990]:
Jesse James, the reader will recall, is riding away from the scene of the crime with his scarf tied round his face just below the eyes in the approved manner. The mask slips, and a bystander, who has studied the ‘wanted’ posters, recognises him. The bystander now knows, surely, that it was James who robbed the bank. But Nozick has a problem: there is a possible world, and a ‘close’ one, in which James’ mask didn’t slip, or didn’t slip until he was already past the bystander; and in that world the bystander wouldn’t believe that James robbed the bank, although it would still be true that he did. So Nozick’s condition [N1] is not satisfied, and he is threatened with having to say that the bystander doesn’t know that it was James, even though the mask did slip. So his analysis looks like ruling out something which is as good a case of knowledge as one could wish for [p. 22].
Nozick is already equipped with a reply to the ‘Jesse James’ counterexample, akin to that employed in the Grandma case [See endnote 1]. In brief, he may simply argue that in worlds in which the mask did not slip, the method employed by the bystander would be different. Thus, given the version of Nozick’s counterfactuals revised to include the subject’s method, worlds in which the mask did not slip would not be included in the relevant nearby possible worlds.

However, to the extant that this reply is effective in preserving the bystanders knowledge in the Jesse James case, it is also effective at preserving the GLR subject’s ‘knowledge’ that (a). In GLR, the computer program, as the locus of reliability, constitutes part of the method by which S arrives at her belief that (a). Thus, by (N1*), all worlds in which the computer program is different or the computer is missing, a different method is being used and that world eo ipso fails to count as nearby.


1 Counter examples such as the Grandma case has prompted Nozick [1981, p. 179] to revise (N1) and (N2), limiting them to the same method (i.e., vision):

(N1*) If p were true, S (using M) would believe that p

(N2*) If p were not true, then S (using M) would not believe that p


Craig, E. [1990], Knowledge and the State of Nature. Oxford: Clarendon Press.

Lewis, D. [1973], Counterfactuals. Oxford: Basil Blackwell.

Nozick, R., [1981], Philosophical Explanations, Cambridge: Cambridge University Press.

Thursday 1 March 2007

Causal vs. Rational Explanations (Part 1)

According to many J-externalists, a belief is only justified if it is caused in the right sort of way (for example, by a reliable process). Thus, we arrive at (J-Ext[C]):
(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 [1981] 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.