Does disjunctivism about perceptual experience provide a
satisfactory response to the sceptic?

I. Introduction

Disjunctive accounts of perceptual experience have been advanced by Hinton (1973), Snowdon (1990) and others (e.g. Martin 2004) as an alternative to traditional accounts of perception that conceive of such experience on the model of an externally caused ‘inner object’ or event. Whilst generally regarded as a thesis concerning the nature and individuation of experience, some philosophers — chiefly John McDowell (1982; 2008) — have emphasised the theory’s epistemological benefits, claiming that it is capable of explaining how we can have knowledge of the external world as opposed to knowledge of mere appearances — an issue that dates back to the work of Descartes (1641), Hume (1739; 1748), Locke (1690), and others. This essay evaluates whether the disjunctivist conception of perceptual experience is able to yield a satisfactory response to such external world scepticism and, if so, what kind of a response it is. In particular, I will focus upon McDowell’s claim that disjunctivism removes a crucial ‘prop’ upon which such scepticism depends, thus placing the disjunctivist on a firmer dialectical footing than his opponent — a claim that is vigourously denied by Wright (1982; 2008). I begin by describing the disjunctivist conception of perceptual experience in Section II, followed by McDowell’s ‘epistemological disjunctivism’ in Section III. Section IV deals with the issue of higher-order scepticism, and I conclude the final section with some remarks concerning the effectiveness of the disjunctivist response.

II. Perceptual Disjunctivism

The central claim of disjunctivism is that the veridical perception of an external object X and a phenomenally indistinguishable hallucination of X do not, as a matter of conceptual necessity, share a common psychological or experiential element. Rather, in the genuinely perceptual or ‘good’ case, the experience is essentially relational, since it relates the subject to an external object; e.g. a zebra (to borrow Dretske’s [2005] example). In the non-perceptual or ‘bad’ case, the experience is non-relational since it only involves there seeming to be a zebra in front of me, and thus has no external object. By application of Leibniz’s Law, a relational and non-relational experience cannot be numerically identical, since they have different properties, thus giving rise to the so-called disjunctive conception of experience. My experience of it looking to me as if there is a zebra in front of me is either a case of my seeing that there is a zebra or of my imagining, hallucinating, etc. that there is a zebra, where the two disjuncts are externally, rather than internally, individuated. Whilst the disjunctivist is not committed to maintaining that the two cases have literally nothing in common, such as the subject’s brain state or how the experience represents the world as being, the claim is that they constitute two different types of experience — or at least that this cannot be ruled out a priori (Snowdon 1990: 129). This may be contrasted with the traditional ‘Lockean’ conception of experience as an inner process or state that is common to both veridical and non-veridical cases, and which in a materialist theory of mind might be identified with or supervene upon a subject’s brain state, for example.1

Perhaps the greatest advantage of such ‘perceptual disjunctivism’ is its ability to explain how perception can make external objects available for demonstrative thought (Snowdon 1990: 143). On the Lockean conception of experience, it is unclear what makes it possible for me to think of that particular zebra, even when it is right in front of me, since the psychological experience that I enjoy is non-relational, and therefore logically and metaphysically independent of the object itself. In order to bridge this gap, some further (e.g. causal) condition must be satisfied since the very same experience would be compatible with there being no such external object. The disjunctive conception of perceptual experience, on the other hand, conceives of the subject as standing in some particular relation (e.g. that of seeing) to an actual object, from which the appearance cannot, so to speak, become ‘detached’, thus making the object available for demonstrative thought. The relationality of perceptual experience makes it essentially object- or world-involving, as opposed to hallucination, which is a purely internal phenomenon.2

Before moving on to consider the epistemological significance of disjunctivism, it is worth noting its connection with some broader philosophical themes. The disjunctivist thesis essentially amounts to a claim about the scope of experience. The traditional conception of experience is that it has narrow scope, with experiences being individuated phenomenologically by virtue of their representational content or phenomenal character. The disjunctive conception, on the other hand, claims that experience has broad scope with experiences being individuated epistemologically on the basis of factors external to the subject. Just as externalism about meaning (e.g. Putnam 1975; Burge 1979) or representational content (Tye 1993) is intended to overcome problems concerning the individuation of thoughts or sensations by taking external contextual factors into account, perceptual disjunctivism is intended to explain how the nature of experience can differ even where the content of those experiences is phenomenologically indistinguishable. Corresponding to these notions of broad and narrow experience are two different notions of justification. Let us say that an individual is subjectively justified, or S-justified, if and only if they have good reason to believe X and are ‘epistemically blameless’ in the sense that they have done nothing wrong in their method of acquiring the relevant belief. Alternatively, a subject is all-things-considered justified, or A-justified, if and only if, were they in possession of all the facts, they would be justified in believing X.3 External world scepticism can be described as attempting to drive a wedge between S- and A-justification, claiming that we are only ever entitled to claim the former, whilst only the latter is capable of yielding knowledge. McDowell’s response to this challenge is both subtle and radical since it attempts to undermine the plausibility of the sceptic’s position by reversing the direction of explanation for what is required for knowledge, as described below.

III. Epistemological Disjunctivism

McDowell’s response to external world scepticism has two distinct phases, or parts, each of which I shall consider in turn. Firstly, the disjunctive conception of experience is used to explain how we can have direct, non-inferential knowledge of the external world. This is intended to secure the possibility of first-order knowledge in the face of sceptical doubt. Secondly, a form of transcendental argument is employed to undermine the plausibility of the sceptic’s own account of knowledge. This is intended to shift the burden of proof away from the common-sense notion of knowledge that we ordinarily employ, and which McDowell’s account supports, and onto the sceptic, who must then give good reason why we should call our everyday knowledge claims into doubt. The issue of second-order knowledge, i.e. our knowing that we know, is not directly addressed by McDowell, but I will argue that a similar strategy may be employed as for first-order knowledge using the disjunctive conception of experience to justify our second- and higher-order knowledge claims.4 It is important to note that at no point does McDowell profess to have refuted the sceptic, but rather his intention is ‘diagnostic’ (McDowell 1992: 378). Indeed, he agrees with Stroud that ‘the worst thing one can do with the traditional question about our knowledge of the world is to try to answer it’ (Stroud 1980: 56, in McDowell 2008: 384). His strategy does not therefore aim to convince the sceptic of the falsity of his argument on some mutually acceptable grounds, but rather to gain dialectical advantage by undermining the coherence and apparent attractiveness of the sceptical position. This will become relevant when evaluating the success (or otherwise) of McDowell’s epistemological disjunctivism.

McDowell (2008: 378–9) maintains that the initial plausibility of external world scepticism (hereafter simply referred to as ‘scepticism’) stems from the fact that the traditional Cartesian view of perceptual knowledge does not adequately secure the possibility of epistemic access to worldly facts. On the narrow conception of experience described above, perceptual experience warrants belief — and thereby knowledge — only when it stands in the appropriate (typically causal) relation to the relevant state of affairs in the external world. However, since precisely the same experience could be enjoyed in the absence of this state of affairs — in the case of a hallucination, for example — such experience can at best give defeasible warrant for belief, since it cannot yield knowledge unless the relevant external condition is satisfied; e.g. when there really is a zebra in front of me. For McDowell, this places perceptual knowledge on dubious foundations since the ‘gap’ between what experience warrants and knowledge makes it easy for the sceptic to claim that the necessary conditions may not have been satisfied due to some as-yet-unconsidered factor, such as our being deceived by a malicious demon (Descartes 1641: 15), by being a ‘brain in a vat’ (Putnam 1981), or through the presence of some cleverly disguised mules (Dretske 2005). This amounts to the claim that, since perceptual experience only involves its seeming to us that p, such experience can only warrant disjunctive beliefs of the form: either we are perceiving that p or we are imagining (hallucinating, etc.) that p. This places the sceptical scenario on precisely the same footing as that of veridical perception. Expressed in the terms defined above, when conceived as having narrow scope, perceptual experience can only yield S-justification, and never A-justification, since no possible evidence is sufficient to rule out the possibility that we are being systematically deceived.

By rejecting the Lockean view in favour of a disjunctivist account of perceptual experience as individuated in terms of its epistemological — rather than phenomenological — properties, McDowell aims to prevent the first-order sceptical argument from gaining a foothold. On this view, veridical perceptual experience is relational by definition and so involves a subject standing in a particular relation to some external world object.5 The presence of the object is intrinsic to the nature of the experience, since on the disjunctivist view without it the subject could no longer be said to have had the same experience. In the ‘good’ case, perceptual experience warrants the belief that there is, for example, a zebra in front of me, since the experience itself entails that the object is present. In the corresponding ‘bad’ case — e.g. in the presence of a cleverly disguised mule — it merely seems that such an object is present, and so any resulting belief that there is a zebra would be unwarranted. In contrast to the Lockean picture where non-disjunctive experience only warrants disjunctive (i.e. sceptical) belief, we now have two disjuncts, one of which warrants belief (or knowledge) and the other which does not, but both of which are phenomenologically indistinguishable to the subject. On McDowell’s picture, however, the fact that the subject may not know which disjunct their experience falls under does not undermine their epistemic standing in the ‘good’ case. At worst, they may form an erroneous (i.e. unwarranted) belief by mistaking a hallucination or fake for the real thing, but this is different to saying that their warrant is defeasible. Indeed, it is arguably the notion of defeasibility, which arises from the narrow conception of perceptual experience, that enables the sceptic to claim that we only ever have S-justification, since we cannot know whether the relevant external conditions have been satisfied. For McDowell, on the other hand, we can have both S- and A-justification in virtue of our direct epistemic access to the facts through our faculties of perception and higher-order cognitive abilities.

It is crucial to McDowell’s account that the reason or justification which warrants perceptual knowledge is not something over and above or presupposed by experience, but perceptual experience itself. Thus, instead of perceptual justification (e.g. seeing a zebra-looking object) being distinct from the beliefs that it warrants (i.e. that there is a zebra), my seeing that there is a zebra directly warrants my belief, since the experience already ‘takes in’ the relevant fact (McDowell 1982: 472). This closely matches ordinary linguistic practice, since when prompted to justify a given piece of perceptual knowledge we typically respond by saying that we just see that it is so, rather than offering any independent justification in support of this fact or the reliability of our perceptual faculties.6 Wright (1982: 345), however, rejects this proposal, claiming that it presupposes precisely what the sceptic denies, i.e. that there is an external world, making it unsuitable for use in an argument that purports to grant knowledge of the external world since it is effectively question-begging. McDowell (2008: 384–5) responds by noting that ‘the point of the disjunctive conception is not to improve our resources for such arguments’, but rather to ‘remove a prop’ (Wright’s own phrase) upon which such scepticism depends; i.e. the assumption that perceptual experience cannot by itself ‘reveal how things are’ (ibid.), but instead stands in need of independent justification. By rejecting this assumption, the disjunctivist effectively blocks the possibility of first-order doubt as to whether such justification is available, since it is no longer separable from the experience itself, instead forcing the sceptic to concentrate upon the second-order issue of whether the experience is in fact perceptual or not, as discussed below. Consequently, Wright’s (2008: 398) insistence that a disjunctive conception of experience fails to warrant knowledge or belief is beside the point, since it is not the disjunction as a whole to which warrant is attached, but to each of the disjuncts (McDowell 2008: 386). This insistence demonstrates the pull of the precisely the narrow conception of experience that the disjunctivist denies, effectively conflating the issue of whether a subject has warrant with the separate question of whether the warranting status of an experience is accessible to the subject, where the latter is a matter of second-order knowledge.

The model of knowledge that McDowell presents is one in which the subject is genuinely ‘open to the world’ and the facts within it without requiring the satisfaction of further (e.g. causal) conditions. Due to its relational nature, the broad conception of perceptual experience is essentially world-involving, and so there is nothing to come between the subject and their knowledge of the world in the ‘good’ case from which the sceptic can construct his counter-argument. Although this may show how perceptual knowledge of the world is possible, it falls short of banishing sceptical doubt altogether since there is as yet no way for the subject to tell whether her experience is in fact perceptual or not, since (by stipulation) the ‘good’ case is subjectively indistinguishable from the ‘bad’.7 At this point in the dialectic, the sceptic would seem to have two options. He can either accept McDowell’s account of perceptual experience and redeploy his argument against the possibility of second-order knowledge, or else reject the disjunctivist conception of experience upon which it is based. However, since it cannot be assumed a priori that disjunctivism is false (Snowdon 1990: 129), it is not clear that the latter option is available, and so the sceptic must directly confront the legitimacy of second-order knowledge claims.8

IV. Second-Order Scepticism

Having secured the possibility that we have perceptual knowledge of the external world, we now turn to the second part of McDowell’s argument, which concerns the issue of whether we can know (or claim) that we have such knowledge. Rather than attempting to argue for this from a neutral starting point that is acceptable to the sceptic — a task that he acknowledges to be futile (McDowell 2008: 386) — McDowell instead employs a transcendental argument aimed at undermining the apparent coherence and plausibility of the sceptic’s own position (ibid. 382). The argument proceeds from the premise that, given the importance and centrality of the concept of knowledge in our everyday experience as a bearer of objective significance, we are rationally bound to adopt a model of knowledge that can make sense of this fact. After all, if our concept of knowledge were completely without foundation then we would be unable to make sense of many of our everyday practices, including perception, learning, scientific investigation, and so on. McDowell claims that the sceptic both grants that our knowledge aims to have ‘objective purport’ whilst simultaneously denying that it can do so in practice (ibid. 380). This position is unstable since it undermines the very idea of knowledge that the sceptic is presupposing, as well as failing to make any of the above practices intelligible. The disjunctivist, on the other hand, can plausibly claim that in the ‘good’ case, experience does indeed have objective purport, and so the distinction between knowing and not knowing is well-founded, thereby rendering our practices intelligible. All other things being equal, we should prefer a model of knowledge that is able to do this, thus making the disjunctivist’s account of knowledge more plausible than the sceptic’s.

This argument is all well and good, but even if the sceptic were to grant McDowell his conclusion, it is still possible (although perhaps unlikely) that all of our experience falls under the ‘bad’ case. After all, this is precisely what the machinations of the Cartesian demon or vat-scientist were supposed to illustrate: that it is entirely consistent with the content of our experience (narrowly construed) that all of our beliefs could turn out to be false for a reason that it is beyond our powers of discrimination to discount. Whilst McDowell appears reluctant to engage with this possibility, a suitable McDowellian response may perhaps be given along the following lines. Just as our first-order perceptual abilities place us in a direct relation to worldly objects and facts, we also have second-order cognitive abilities that enable us to tell from the surrounding context and situation whether these first-order experiences are in fact veridical.9 Indeed, most if not all perceptual experiences contains some indication of their own veridicality, which is why we are inclined to take some experiences at face value and to doubt others; e.g. a fleeting glimpse, unconvincing facsimile, or dream-like visual impressions. This is not to say that such second-order abilities are infallible any more than our perceptual abilities are infallible since we do not know in all cases whether we are being deceived. However, the McDowellian conception of knowledge is perfectly able to explain how it is that we have direct epistemic access to the fact that we can and do perceive veridically in a wide variety of cases. Just as having a particular (broadly constituted) perceptual experience can itself warrant first-order belief or knowledge, the very same experience, along with the appropriate contextual and cognitive factors, can warrant the corresponding second-order knowledge claim. As with first-order knowledge, such claims do not require the existence of any independent justification or warrant over and above the initial perceptual experience along with our previous training and experience in recognising instances of ‘good’ and ‘bad’ cases. Thus, the claim is not that we always — or even most of the time — know whether or not we perceive veridically, but that in the ‘good’ case, we can know that we know since our higher-order cognitive abilities are able to ‘take in’ this higher-order fact. Of course, there is still the possibility that in the ‘bad’ case we may be mistaken, but the possibility of such false knowledge claims does not justify the sceptical conclusion that none of our knowledge claims are warranted, since the disjunctivist’s conception of experience has already shown how we can have direct epistemic access to the facts in the ‘good’ case.

The structure of the above argument exactly parallels that of McDowell’s argument for first-order knowledge. Once again, the sceptic cannot rule out the possibility that the acquisition of such higher-order knowledge is possible, but will seek to cast doubt upon its reliability, shifting the argument to an even high-order form of scepticism. Surely, he will claim, any malicious demon or evil scientist worth their salt would set things up so that it would seem to us as if we had knowledge even where we have none? Here it may seem as if the disjunctivist response does little more than to set up an infinite regress in which both sides perpetually claim victory by invoking ever higher-order cognitive abilities and higher-order sceptical doubts. However, at this stage the McDowellian disjunctivist can justifiably claim that their model of knowledge offers a more plausible basis for our everyday use of the term than that of the sceptic, which seeks to render the very possibility of knowledge unobtainable, thereby rendering the concept meaningless.10 The disjunctivist account of first-order perceptual and higher-order cognitive abilities is therefore better placed to make sense of our everyday talk and practices surrounding knowledge whilst acknowledging that we may be more or less fallible in individual cases. What it denies is that such fallibility requires us to engage with the sceptical argument on its own terms, since both first- and higher-order knowledge are, so to speak, already within our grasp.

V. Conclusion

Whether disjunctivism is capable of supporting a satisfactory response to external world scepticism largely depends upon the issue of who such a response is required to satisfy. McDowell’s epistemological disjunctivism will certainly be unsatisfactory to any committed sceptic, who will accuse him of rejecting the Lockean conception of experience out of hand, or to those who will settle for nothing less than a full-blown refutation of the sceptic’s argument. On these views, perhaps the best that could be said about McDowell’s account is that it re-describes the facts to show how knowledge might be possible, but falls short of giving any decisive response to the sceptic, and ultimately fails to engage with the argument. Such a conclusion would, however, be unwarranted since it both underestimates the resources available to the disjunctivist about perceptual experience as well as misreading the whole tenor of McDowell’s approach which was to avoid the need to engage with scepticism on its own terms — a task that arguably never had any prospect of success in the first place.

Perhaps a better way of understanding McDowell’s anti-scepticism is as a form of Wittgensteinian ‘philosophical therapy’ (McGinn 1997: 23), designed not to refute the sceptic, but to relieve us of an anxiety concerning the demands that knowledge places upon perceptual experience. As such, we need only be satisfied that first- and higher-order knowledge is available to us in the ‘good’ case, and that the sceptic’s argument, whilst acknowledging its initial appeal, need not prove compelling provided that we are willing to accept that justification for both types of knowledge can arise from having a particular kind of externally individuated perceptual experience. By conceiving of knowledge in terms of direct epistemic access to the world, or facts, rather than attempting to build it up from subjective justification plus the satisfaction of some further external condition, McDowell rejects the sceptical premise that we require independent justification over and above perceptual experience — our primary means of knowing about the world. This in turn underpins an attack on the sceptic’s model of knowledge, which fails to account for our everyday ‘forms of life’, thereby shifting the burden of proof back onto the sceptic. In this way, McDowell seeks to reassure us that we should not be seduced into letting the logic of the sceptic’s position undermine our confidence in our everyday practices and knowledge claims. When expressed in these terms, disjunctivism supports a powerful and effective remedy against what tempted us towards scepticism in the first place, thus putting our sceptical doubts back into perspective, rather than placing them at the forefront of our epistemological concerns.

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