As we have characterised them, relationalism and intentionalism purportedly offer competing accounts of the phenomenal character of experience (Sects. 2 and 3). Much of the debate between them therefore turns on the adequacy of these accounts. Here we focus on four such issues concerning the duality of perceptual appearances (Brogaard), the relational account of perceptual appearances and illusions (Brewer), the relevance of conscious experience for the possibility of thought (Eilan), and the sense of presence (Dokic & Martin), respectively.

Berit Brogaard

In ‘The Silence of the Senses’, Charles Travis (2004, 2013a) argues that perceptual experiences cannot have representational contents because they are, in an important sense, equivocal or indeterminate between multiple ways that the world might be. Thus, in what one of us has elsewhere called Travis’s “argument from looks” (Wilson forthcoming), “in perception, things are not presented, or represented, to us as being thus and so. They are just presented to us, full stop” (Travis 2004: 65).Footnote 23 Travis’s argument for this point draws on the various kinds of looks—comparative, epistemic, phenomenal—that might conceivably make such representations available to the subject, and concludes that none is able to do so. Thus, even if there were such a thing as perceptual representation, it would be cognitively inaccessible to the subject and so explanatorily redundant.Footnote 24

Berit Brogaard (this issue) offers a new line of response to Travis.Footnote 25 While Brogaard agrees with Travis that representation is not an essential feature of perceptual experience, she argues that empirical evidence concerning the duality of appearances favours the view that, for perceivers like us, visual experiences do represent the world as being some particular way, and so are not equivocal in the manner that Travis suggests.

Brogaard takes Travis’s argument to concern the independence of perceptual content from the agent’s epistemic states: beliefs, judgements, and so on. This is what we would expect if, as per representationalist orthodoxy, the contents of some such states—for example, the belief that some particular tomato is red—derive from the contents of experience, e.g. seeing the red tomato, rather than the other way around.Footnote 26 If, in addition to this, the contents of experiences were themselves dependent upon the contents of beliefs, then the relationship between the two would be circular, and so not explanatory. Brogaard argues, however, that Travis’s denial that experiences have any recognisable content, or “face value”, fails to do justice to visual phenomenology. According to Brogaard, visual experiences can and do favour one interpretation over others, and so things can look to be a particular way independently of the subject’s epistemic states. Consequently, Brogaard argues, a key premise of Travis’s argument is false, and intentionalism is again off the hook.

Brogaard concludes by offering a positive “Argument from Phenomenology” in favour of representational content. Like Susanna Schellenberg’s “Master Argument” (2011), Brogaard argues that we cannot fully explain visual phenomenal character without appealing to the notion of “perceptual seeming”. According to Brogaard, such “seemings” favour intentionalism over non-representational alternatives. Of course, anti-representationalists might in turn dispute whether “seemings” are wholly perceptual as opposed to being complex, partly epistemic states, as with Brewer’s ‘thick’ notion of looks (Sect. 5.2). Nevertheless, since the phenomena Brogaard describe involve appearances that are robustly independent of the subject’s beliefs, in order to avoid her conclusion the anti-representationalist must either (a) posit the existence of some further non-doxastic state that falls between ‘pure’ experience and belief, or else (b) provide an analysis of such phenomena in terms of existing epistemic states. Brogaard’s Argument from Phenomenology can therefore be seen as challenging the adequacy of relationalism in accommodating the human visual system’s adherence to certain perceptual principles.

Bill Brewer: Thin and Thick Looks

According to Brewer’s ‘Object View’ (Sect. 4.1), an object’s visually appearing or “thinly” looking F is explained by its possessing “appropriate visually relevant similarities with paradigm exemplars of F” (this issue), i.e. objects that are paradigmatically F.Footnote 27 Thus, the lines of the Müller-Lyer illusion, for example, look to be of different lengths not because we represent them to be such, but because the presence of the arrowheads causes them to visually resemble paradigm cases of three-dimensional convex and concave edges that are closer to or further away from the subject, respectively (Brewer 2008). Due to the phenomenon of size constancy, our visual system automatically adjusts for such depth cues, causing the lines to appear as being unequal in length, as would in fact be the case in the equivalent three-dimensional figure. Despite their dependence upon contingent properties of our visual systems, such similarities are nevertheless mind-independent in that they are grounded in objective features of external objects independently of the subject’s thinking or representing anything to be so. Indeed, Brewer argues that such illusions are more problematic for orthodox representational views, which are committed to there being some fact of the matter as to precisely how long subjects represent the lines as being (ibid.).

Thin looks alone, however, are insufficient to explain the phenomenology of figures like the Necker cube or duck-rabbit which appear to flip between different possible appearances. Nor do they explain why we tend to register some of an object’s similarities over others. A white piece of chalk illuminated by red light, for example, possesses visually relevant similarities to both (a) red objects under normal illumination conditions, and (b) white objects illuminated by red light. Yet, even given that looking white-in-red-light is a way of looking white, we would not ordinarily say that white chalk in red light “looks white”, except possibly in Chisholm’s (1957) epistemic use of ‘looks’. To overcome these objections, Brewer appeals to a “thick” notion of looks which involves the “perceptual registration” of a particular visual similarity or appearance. Thus, in respect of its colour, the chalk thinly looks both red and white-in-red-light, but thickly only looks red, since this is the property that our visual systems typically register under normal circumstances. Brewer takes the central cases of perceptual registration to involve the application of a concept, but allows that there may be forms of registration, and so thick looks, that are non-conceptual. Interestingly, both of these cases can also be described in terms of the tokening of representational elements. Thus, Brewer’s theory accords with Brogaard in allowing a role for representational content in determining the phenomenal character of experience in the thick sense. Brewer argues, however, that this does not undermine the Object View’s claim to be a form of relationalism, since (a) it fundamentally characterises experience in terms of the subject’s relation to external mind-independent objects, and so as non-reducible to its representational content, and (b) the representational elements in thick looks are themselves dependent upon the obtaining of this perceptual relation.

Naomi Eilan

In Reference and Consciousness, John Campbell (2002) argues that only a relational view of perception can adequately make sense of how conscious experience plays a crucial role in enabling demonstrative thoughts about the categorical properties and mind-independent objects that we perceive. According to relationalism, one is confronted with the very mind-independent objects that demonstrative judgments refer to, thereby explaining how perception can provide knowledge of the semantic values of such demonstratives. Conversely, Campbell argues that representational views fall short of accounting for the explanatory role of experience because by postulating conceptual content they presuppose what is to be explained: the possession and ability to use demonstrative concepts.Footnote 28 To counter this argument, a representationalist could either (a) deny that experience plays the explanatory role that Campbell assigns to it (Burge 2005; Cassam 2011), or (b) argue that representationalism succeeds in explaining the role of experience in allowing us to have a conception of objects in the world as mind-independent, and of properties as categorical. Indeed, many representationalists, and in particular proponents of phenomenal externalism (cf. Tye 1995; Lycan 2001), would argue that the phenomenal character of experience plays precisely such a role in explaining the objective import of experience through its representational content.

Naomi Eilan (this issue) challenges both of the above strategies. She begins by formulating a challenge to representationalism on Burge’s behalf, which she labels “Burge*’s Challenge”. It takes the form of the following dilemma: either (i) endorse the general structure of Burge’s representational account of perception, which she labels “Caused Representation”, and give up on a role for consciousness, or (ii) relinquish Caused Representation, and defend a role for consciousness. As noted above, Burge himself opts for the first horn. On this account, everything there is to say about how perceptions achieve objective import also applies to blindsight (Weiskrantz 1986), which is often described as a case in which the subject lacks conscious experience despite enjoying a perception that accurately represents the properties of the external object.

The alternatives are to opt for the second horn, or to reject the dilemma. Many defenders of representationalism about perceptual experience would argue for the latter option: to give consciousness a role within a representationalist framework. To test this, Eilan formulates a sceptical challenge for claims to the effect that perceptions have objective import, which is to explain what makes it the case that we perceive particular categorical properties rather than their structural equivalents. She argues that it can be met only by relational adoptions of the second horn of the dilemma, and in particular by those versions that appeal to Russellian acquaintance with mind-independent objects and their properties, where such acquaintance is conceived of as “knowledge of things” independently of “knowledge of truths”.

The paper ends with a comparison between Eilan’s position and that adopted by phenomenal intentionalists (Horgan et al. 2004; Kriegel and Horgan 2008), who would reject the dilemma by endorsing Burge’s approach to the representational content of perception while at the same time insisting that consciousness is integral to perceptual forms of representation. Eilan argues that such accounts cannot meet the sceptical challenge in a way that, contra Burge and according to our intuitions, gives consciousness a role in delivering objective import.

Jérôme Dokic and Jean-Rémy Martin

Another crucial aspect of the phenomenology of experience is the sense of reality, also known as a sense or feeling of presence. Against philosophers who see this sense of presence as constitutive of genuine perception, Jérôme Dokic and Jean-Rémy Martin argue that it is two-way independent from the contents of perception, and that this has an important implication for the debate over intentionalism and relationalism which results in intentionalism being unable to account for the sense of reality.

Dokic and Martin distinguish between two different phenomena that are commonly referred to by the expression “sense of presence”: (i) the sense that an object is real, or “sense of reality”, which is the central concern of their paper; and (ii) the sense that we are acquainted with the object itself rather than some surrogate or representation, which they call “sense of acquaintance”. To distinguish these, the authors consider studies on derealisation, a disorder in which, they argue, patients are best described as lacking the sense that what they experience is real while preserving otherwise normal perceptual capacities. This suggests that the sense of reality is not constitutive of perception. Rather, it is a specific experience that is “enjoyed over and above the perceptual experience itself”, and which might fail independently of other perceptual capacities.

While the case of derealisation shows that experience can occur without a sense of reality, three other cases show that derealisation may occur without a genuine experience: (i) an experience, common in cases of Parkinson’s disease, in which patients report that they vividly perceive the presence of a person without seeing, touching, hearing, or smelling that person, who is not in fact there; (ii) recent studies on virtual reality suggest that increasing the realism of spatiotemporal content doesn’t correlate with an increased sense of reality, nor vice versa; (iii) certain forms of hallucination where quite unrealistic entities are experienced as part of the world, presenting a similar dissociation of sense of reality from level of realism of the content of experience. Such cases suggest that the sense that an object is present does not require that the object is perceived.

Further to these empirical considerations, Dokic and Martin provide theoretical consideration for the claim that the sense of reality is not constitutive of perceptual experience. They suggest that the best explanation for this phenomenon is that it is an affective component, akin to a metacognitive feeling, “based on various reality-monitoring processes, and processes that control one’s spontaneous judgment of reality” (this issue). With this understanding of the sense of reality in place, the authors formulate the following challenge for intentionalism. Since genuine perception is possible without the sense of reality, how should perceptual experience be characterised in contrast to other kinds of sensory mental states, such as imaginings, which are clearly representational? The natural way for the intentionalist to do this would be to claim that, contrary to these other states, the content of perception asserts that the representation is veridical. But this conflicts with the above empirical and theoretical considerations that speak in favour of their independence. The alternative would be to deny that perception is fundamentally different from phenomena such as imagination, where the only distinction between the two is that the former, but not the latter, is accompanied by the distinctive sense of presence. According to Dokic and Martin, relationalism, on the other hand, “seems to be able to explain the specificity of perception independently of the instantiation of the sense of reality. Unlike imagination, perception is a relation to the world, and the veridicality of perceptual experience does not rest on the truth or correctness of a representation” (ibid.).