Abstract
This article re-examines Ned Block‘s (1997, 2007) conceptual distinction between phenomenal consciousness and access consciousness. His argument that we can have phenomenally conscious representations without being able to cognitively access them is criticized as not being supported by evidence. Instead, an alternative interpretation of the relevant empirical data is offered which leaves the link between phenomenology and accessibility intact. Moreover, it is shown that Block’s claim that phenomenology and accessibility have different neural substrates is highly problematic in light of empirical evidence. Finally, his claim that there can be phenomenology without cognitive accessibility is at odds with his endorsement of the 'same-order-theory' of consciousness.
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Notes
Block also allows sensations like pain to be representational in this sense, but his point is that they need not be and even if they were, then this would not be all there is to them.
In addition, Block distinguishes a form of reflexive consciousness which he associates with a higher-order thought model (Rosenthal 2004), and self-consciousness in the sense of a sophisticated knowledge of one’s own mental states, presupposing the possession of the concept of ‘self’.
Overgaard (2011) also points to the unresolved issue whether blindsight patients actually do have residual visual phenomenology on the basis of their reports regarding a “feeling of knowing” what there is in their visual field, indicating a correlation between their feeling and good performance. Yet, for the purposes of this discussion, this issue is not problematic for the following reasons: (1) Block himself treats blindsight as being unconscious tout court, (2) the possibility raised by Overgaard’s interpretation of various reports does not drive a wedge between phenomenology and accessibility, and (3) this possibility would merely amount to a case of what Koch (2004) calls “gist perception” (see below). In any case, if there is residual phenomenology, then it is merely a “degraded conscious vision”, as Overgaard acknowledges, not a full-fledged phenomenology of details. For Block’s overall argument to go through, it would have to amount to a “rich” visual phenomenology (more on this in the next section).
Block himself takes cases of A-consciousness without P-consciousness to be empirically unlikely (personal communication).
The fact that the first possibility is not so much-discussed might have to do with the fact that functionalism is still the dominant account of the mind; and for functionalists (like e.g. Dennett 1991), the possibility of access without phenomenology is, of course, very welcome since it is, in their view, what is in fact the case.
Of course, I do not claim that the alternatives mentioned are exhaustive. There may be others but it is not the point of this paper to investigate this example in detail. I will argue for the first option later in the paper.
It might appear strange to the reader that Block relies on subjective reports at all, since these are not the kind of data that could support a case of phenomenology without access. Since any report relies on cognitive access, it cannot inform us about the presence of an inaccessible conscious representation. A report about such a representation would be indistinguishable from a report about a totally unconscious representation, e.g. “I see nothing”. In a recent paper, Cohen and Dennett (2011) emphasize this point and argue that theories like Block’s which completely dissociate phenomenology from function “are inherently unfalsifiable and beyond the scope of science, because inaccessible conscious states are intrinsically off-limits to investigation” (ibid., 358). The problem for Block is that he obviously thinks that phenomenology can be scientifically investigated; the problem for Cohen and Dennett is that their own argument could be turned against them to the effect that they have thereby shown that functionalism about consciousness is false: since “science necessarily relies on cognitive functions in order to investigate consciousness”, but consciousness is not exhausted by those functions, consciousness cannot be approached scientifically.
This is relevant, since the specification of content provides the answer to the question what the subject is supposed to have access to. Regarding Sperling’s experiment and Block’s claim that subjects are phenomenally aware as of all the specific items, one may ask, for example, what an ‘item’ is. There are of course many ways to single out something as an item. Any of the 12 letters may count as an item, but also the whole array counts as an item. Moreover, there are various ways to group items to get other items (e.g., a row of four letters may count as an item). Block obviously identifies a single letter as the relevant specific item.
Sid Kouider (Kouider et al. 2007) proposes a similar interpretation, but instead of distinguishing between generic and specific content he puts it in terms of fragmented letters which are phenomenally conscious and on that basis also accessible: “subjects have a transient and degraded access to fragments of all the letters in the grid. As subjects are not expecting anything other than letters, fragments are used to reconstruct as many letters as possible” (2007, p. 511). Kouider designed a variation of the Sperling- experiment, where he replaced some of the letters with non-letters or letters being turned on their heads. After offset of the stimulus he presented an array containing both letters which had not been included in the original array, and the turned-around letters which had been presented in the original array. When subjects had to decide whether any of those had been presented in the original array, they generally reported the letter, despite the fact that it had not been presented before, but they did not report the non-letter, which had been included (see also de Gardelle et al. 2009).
A crucial factor both in the putative examples for phenomenal without access-consciousness and the present alternative interpretation of the data in terms of indeterminate and determinate content is focal attention. In the pneumatic drill-example, attention is initially directed only at the conversation (or the conversation partner), not at the noise outside, which you may be only peripherally aware of since it is outside your focus of attention. But then, at noon, the noise grabs your attention (or you actively direct it towards it), which results in your being aware of the noise as coming from the pneumatic drill outside.
The concept of self-consciousness may also allow for different levels of complexity and thus encompass various phenomena but this is not the place to elaborate this point further.
Note that this does not imply the view that beliefs and thoughts have qualia. In this context, we can remain neutral on this question. This is so since one need not reduce phenomenal character to qualia, as some philosophers seem to be willing to do. Qualia are supposed to be properties by which two sensations (as of red and as of blue, say) differ from each other. We may call this the ‘qualitative character’ of an experience, in contrast to its ‘subjective character’, which is constitutive of conscious experiences tout court (Kriegel 2005). While not all conscious experiences need exhibit qualitative character, they all have the same property in common, namely, their subjective character. The former may very well be analyzed in terms of content, along the lines suggested by Tye (1995). But the present claim is that subjective character may not be so analyzed, since it is not a matter of a further content being added to the representational content of the experience! This is not the place to argue for this claim but see Schlicht (2011) for a discussion of several (unsuccessful) attempts to explain subjective character in terms of content.
In contrast to representationalist approaches (Tye 1995; Dretske 1995; Rosenthal 2004; Lycan 1996; Carruthers 2000), the difference between an unconscious and a conscious representation may be that the latter is integrated in the right kind of way into the subject’s transient global experiential state, which also includes information about the overall biological (homeostatic) state of the organism as a whole (Damasio 1999). This proposal is based on the assumption that creature consciousness is not only the necessary basis of phenomenal consciousness, but also (at least partly) constitutive of phenomenal consciousness (Bayne 2011). The resulting dynamic neural state of the organism, which includes not only such “proto-self” structures but also the core correlates of representations in various sense modalities, may then be called the “total state of consciousness” (Bayne & Chalmers 2003) of the organism at a time. Once a mental representation is integrated in the right kind of way, it is phenomenally conscious and can be considered as a modification of the organism’s total state of consciousness. Then there is something it is like for the subject to be in this representational state (Metzinger 1995; Van Gulick 2004a; Edelman and Tononi 2000). This is not the place to develop this account in any more detail, but see Schlicht 2011.
One may object that this way of talking only makes sense when one presupposes that visual processing is linear and where attention has a place, thereby ignoring the massively parallel and distributed nature of neural processing (cf. Mole, forthcoming). But the obvious reply is that if the information processing is always a two-way affair, with no major direction, then this is even worse for Block’s case.
These mechanisms of focal attention in visual processing may play a crucial role in the context of integration of information and reduction of uncertainty. This is therefore relevant for the discussion of the preceding sections. If Tononi (2004) is right that consciousness corresponds to the brain’s ability to integrate information, and if information can be defined as the reduction of uncertainty, then a notion of maximally integrated content could be developed, which is content that is fully determined, in contrast to content which is less integrated and thus less determinate.
Another source for doubt regarding Block’s claim concerning a sufficient neural base of phenomenology “in the back of the head” are studies that highlight activations in prefrontal and parietal cortices in association with conscious experience, see Dehaene and Naccache (2001) and Rees et al. (2002). Whether these activations support the view defended here that attention is involved in visual processing or whether it supports a higher-order theory of consciousness, according to which this kind of activation underlies a non-conscious higher-order thought that renders a visual representation conscious (Lau and Rosenthal 2011), is an open question that cannot be decided here.
More recent developments of this position can be found in Kriegel and Williford 2006.
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The material in this paper has been presented at various occasions and I would like to thank the audiences for the feedback that I received. I am especially grateful for Ned Block’s comments at the meeting of the Association for the Scientific Study of Consciousness in Taipei, 2008 where I first presented this paper. For valuable discussions I also thank Anne-Sophie Brüggen, Max Coltheart, Santiago Arango-Muñoz, and again Ned Block. Finally, I would like to thank an anonymous reviewer for valuable suggestions regarding an earlier version of this paper.
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Schlicht, T. Phenomenal consciousness, attention and accessibility. Phenom Cogn Sci 11, 309–334 (2012). https://doi.org/10.1007/s11097-012-9256-0
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DOI: https://doi.org/10.1007/s11097-012-9256-0