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How Rich is the Illusion of Consciousness?


Illusionists claim that phenomenal consciousness does not exist, but merely seems to exist. Most debates concerning illusionism focus on whether or not it is true—whether phenomenal consciousness really is an illusion. Here I want to tackle a different question: assuming illusionism is true, what kind of illusion is the illusion of phenomenality? Is it a “rich” illusion—the cognitively impenetrable activation of an incorrect representation—or a “sparse” illusion—the cognitively impenetrable activation of an incomplete representation, which leads to drawing incorrect judgments? I present this distinction and I classify the most influential illusionist theories along this line of divide. I then offer an argument against the accounts of the illusion of phenomenality in terms of sparse illusion.

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  1. Illusionism is compatible with any view regarding whether or not the set of quasi-phenomenal states forms a natural kind. It is also compatible with any view regarding the existence and the nature of other, non-phenomenal forms of consciousness—such as access-consciousness.

  2. Here, I consider that “fully cognitively impenetrable” means “synchronically impenetrable” (acquiring new information at a single moment, as such, does not substantively impact the relevant representational process) and “diachronically impenetrable in adults” (acquiring new information at an adult age, as such, does not substantively impact the relevant representational process, even over an extended period of time). I set aside the problem of diachronic impenetrability through earlier stages of development in the context of this paper, and I do not require a representational process to possess this kind of diachronic impenetrability to qualify as “fully cognitively impenetrable”. For the distinction between diachronic and synchronic penetrability/impenetrability, see (McCauley and Henrich 2006).

  3. Of course, one could also want to reserve the term “illusion” for what I call “rich illusions”—for example because they think that the processes generating illusions have to be cognitively impenetrable all the way down (as a matter of definition). I do not want to enter in this kind of semantic debate here; most of what I am going to say could be understood and accepted by someone who has this kind of strict understanding of illusions, provided they engage in some renaming—instead of asking “is the illusion of consciousness rich or sparse?” they could ask “is consciousness an introspective illusion, or a mistake we instinctively tend to make on the basis of incomplete introspective representations?”.

  4. Graziano rejects the term “illusionism” (Graziano 2016) to qualify his theory, because he wants to limit the use of the vocabulary of “illusion” to rare and abnormal dysfunctions of a detecting mechanism. However, I think he clearly is an illusionist in the sense I have given the term.

  5. One other way to interpret Graziano’s theory would be to say that our attention schema explicitly represents our internal states as not having any properties outside of the ones it ascribes them. That would make Graziano’s view a rich-illusion account. However, I think that Graziano chooses the first interpretation, as he insists that the attention schema is merely incomplete and schematic (Graziano 2016, p. 104) but not positively incorrect. Moreover, he has confirmed that this was his favored interpretation in conversation.

  6. Pereboom does not explicitly endorse this hypothesis in the book cited, even though he tries to make the case that it constitutes an open possibility. However, for reasons of simplicity, I will speak of this view as if Pereboom endorsed it.

  7. Note that Humphrey, as Graziano, rejects the term “illusionism” to characterize his theory (Humphrey 2016).

  8. I am here only classifying recent illusionist views of consciousness. Some more traditional views, which belong to what Keith Frankish calls “weak illusionism” (Frankish 2016, p. 15), would probably qualify as sparse-illusion views (Armstrong 1968; Carruthers 2000; Levin 2007)—but I will not say more about them here.

  9. This is not to say that all rich-illusion views require an evolutionary explanation of the machinery giving rise to the illusion of consciousness. Given the way I defined cognitive penetrability earlier (a way which exclude diachronic penetrability throughout various stages of development), we can imagine that some views, which would be rich-illusion views in my definition, could explain the illusion of consciousness by appealing to an introspective machinery built or learnt during childhood (for example, on the basis of embodied fallacious cultural schemas or philosophical and religious beliefs). In this case, the illusion of consciousness would not be caused by a species-wide, innate mechanism, which would mean that there might be no need for an evolutionary explanation of the relevant mechanism. However, it seems that major contemporary illusionist theories of consciousness which happen to be rich-illusion views often embrace inneism regarding the machinery leading to the illusion of consciousness, which then creates a pressure to give some kind of evolutionary explanation of the corresponding machinery.

  10. The difficulty arises whether the representational trait is supposed to be explained as an adaptation, or as a by-product of features which are themselves adaptations. Note that, by saying that giving such an evolutionary explanation is a challenge, I do not mean that this challenge could not be met. Humphrey’s view can be seen as an attempt to give an evolutionary explanation (in that case, as an adaptation) of the illusion of consciousness, probably conceived as a rich illusion. In Humphrey’s view (Humphrey 2011), the illusion of entering conscious states, which are represented as eerie, otherworldly states, is adaptive, as it fostered the conviction of our ancestors that human beings and their mental lives had some kind of special value, thus enhancing the drive for survival and reproduction. Of course, one problem with such view is that it seems that the same evolutionary function could have been fulfilled in many different (possibly simpler) ways, without relying on something as complex as the illusory representation of conscious states—for example, by directly designing a strong primitive desire to survive and reproduce. I set aside a more detailed discussion of Humphrey’s view, which would go beyond the scope of this paper.

  11. The argument I am about to give bears some structural similarity with the argument I gave in (Kammerer 2018). In both cases, I argue against some illusionist theories of consciousness, on the basis of the fact that they are unable to predict some of our intuitions regarding consciousness. The main differences between the argument here and the argument I gave back then are: (1) My argument back then was directed against all currently available illusionist theories of consciousness, while this one is only directed at “sparse-illusion views”. (2) My argument back then was based on the inability of illusionist theories of consciousness to correctly predict the strength of realist intuitions regarding consciousness (and on the difficulty we face when we try to entertain the idea that consciousness is an illusion), while I focus here on the strength of anti-physicalist intuitions (or “distinctness” intuitions).

  12. Empirical research on dualist intuitions about the mind has been booming in the last years. See (Chalmers 2018, pp. 13–14) for a recent overview.

  13. For an argument that such rich-illusion views in which the rich illusion is a doxastic illusion [for example, a cognitive illusion or a fallacy akin to the fallacies studied by psychologists of reasoning (Fisk 2004; Pohl 2004; Tversky and Kahneman 1983; Wason and Johnson-Laird 1972)] should be rejected, because they are not psychologically plausible, see (Kammerer 2019a).


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I want to thank Keith Frankish and Sonia Paz Higgins for their comments and their help, as well as the audience at the University of Edinburgh (Designed Minds conference 2017), and three anonymous reviewers from their useful remarks.

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Correspondence to François Kammerer.

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Kammerer, F. How Rich is the Illusion of Consciousness?. Erkenn 87, 499–515 (2022).

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