The integrated structure of consciousness: phenomenal content, subjective attitude, and noetic complex


We explore the integrated structure (or the unity) of consciousness by examining the “phenomenological axioms” of the “integrated information theory of consciousness (IIT)” from the perspective of Husserlian phenomenology. After clarifying the notion of phenomenological axioms by drawing on resources from Edmund Husserl and Maurice Merleau-Ponty (Section 1), we develop a critique of the integration axiom by drawing on phenomenological analyses developed by Aron Gurwitsch and Merleau-Ponty (Section 2 & 3). This axiom is ambiguous. It can be read either atomistically as claiming that the phenomenal content of conscious experience is an integrated complex and holistically as claiming that it is an integrated Gestalt. We argue that the latter reading provides a better characterization of the internal structure of the phenomenal content. Furthermore, the integrated structure of consciousness is not confined to the phenomenal content, but it also extends into the subjective attitude (Section 4). Subjective attitudes and phenomenal contents are interdependent constituents that jointly make up conscious experiences. This implies a novel theoretical challenge to the scientific component of IIT, which is to explain how to accommodate the subjective dimension of consciousness into its explanatory scope (Section 5). IIT can respond in a few different ways, but most importantly, it cannot just ignore it once and for all. As one possible way to address the challenge, we propose introducing a novel construct, noetic complex, to develop a fine-grained model of the neural underpinning of consciousness (Section 6).

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  1. 1.

    For commentaries on the mathematical components of IIT, see for example Barrett (2014), Beaton and Aleksander (2012), de Barros et al. (2016), Peressini (2013), and Tegmark (2016).

  2. 2.

    See Schwitzgebel (2015) for a criticism of IIT in regard to its association to panpsychism.

  3. 3.

    Hereafter, we will italicize the word when it stands for the name of an axiom. For example, “integration” refers to the axiom, and “integration” describes the relevant concept. We will also italicize a word to emphasize it, but then our intention should be clear from the context.

  4. 4.

    Just to add a few comments on the other axioms we will not address in the following: The composition axiom holds that conscious experience has an internal structure. More specifically, it claims that it is composed of what Tononi calls (not unambiguously) “phenomenological distinctions”. The information axiom notes that each conscious experience has a specific phenomenal content. This means that each conscious experience has an informational value by virtue of instantiating one content, among the totality of possible contents it can instantiate. The exclusion axiom describes the idea that the phenomenal content of a conscious experience is exactly identical with what one is consciously aware of in the experience in question. It forbids us from thinking that there might be more to the phenomenal content than one is consciously aware of, or that only part of what one is consciously aware of constitutes the phenomenal content. These axioms invite philosophical questions no less than integration and intrinsic existence. For example, what is a phenomenological distinction? What kind of part-whole relation does it have with conscious experience as a whole? (Composition) Is informational value an essential property intrinsic to experience itself? Or is it something that the theorist attributes to it from the outside? (Information) Can we always draw a definite line between what one is consciously aware of and what one is not? (Exclusion) We will not attempt to resolve these issues in this paper, however. See Cerullo (2015) for a criticism of IIT focused on exclusion.

  5. 5.

    According to Wiese, investigations from the subjective perspective only provide possible solutions to the problem of providing a phenomenological characterization of phenomenal unity. We can determine the actual phenomenological character of a unified experience only by exploring the properties of the subpersonal process that realizes the personal level experience (Wiese 2017, 819). In contrast, we think that the phenomenological characterization should be obtained primarily through phenomenological investigations, which can be, but need not be, informed by subpersonal level investigations.

  6. 6.

    We thank the anonymous reviewer for pressing us to clarify the role of phenomenology in IIT.

  7. 7.

    Michael Cerullo disputes the significance of the phenomenological approach by pointing out that it can lead different theorists to “very different conclusions about fundamental properties of consciousness” (Cerullo 2015, p. 7). This indicates, we suggest, not so much a problem of the phenomenological approach as the difficulty of getting fundamental issues right. In fact, philosophers have arrived at very different conclusions on every fundamental issue throughout the history of philosophy whether or not they preferred the phenomenological approach.

  8. 8.

    Not unlike Merleau-Ponty, Elijah Chudnoff attempts to identify the object of phenomenological analysis by calling it “the total phenomenal state” (Chudnoff 2013, p. 560). However, there is a tension between how they each characterize the phenomenal field and the total phenomenal state. Chudnoff stipulates that a phenomenal state is “an instantiation of a determinate phenomenal property” (Chudnoff 2013, p. 561). Hence, for him, the total phenomenal state is a thoroughly determinate domain. In contrast, for Merleau-Ponty, a central feature of the phenomenal field is its indeterminacy. In fact, he considers it a fundamental problem of both psychology and philosophy of his time that they fail to “recognize the indeterminate as a positive phenomenon” (Merleau-Ponty 2012, p. 7).

  9. 9.

    On another interpretation, the axioms are about the “semantic content” of experience (de Barros et al. 2016, p. 57). We doubt that this interpretation does full justice to the claim that axioms are “about experience itself”. We also doubt that this is how Tononi considers the axioms. The interpretation in question is probably motivated in part by discussions of “concepts” and “conceptual structures” in IIT (e.g., Tononi 2015; Tononi et al. 2016). The vocabulary may suggest that, for IIT, experience consists in the conceptual content of conscious mental states. However, Tononi applies these concepts neither to conscious experiences as such, nor to the contents of mental state. Instead, he uses them to describe a specific property of the subcomponents of the physical mechanism that underpins conscious experience. The relevant property is that of specifying a certain cause-effect repertoire, i.e., a probabilistically distributed set of past and future states causally connected to the current state of the mechanism (e.g., Tononi et al. 2016, p. 452, Tononi 2015, Tononi 2012, p. 301; see also section 5 below). The frequent use of such words like “concept” and “conceptual structure,” therefore, does not justify interpreting phenomenological axioms as claims about the semantic or the conceptual content of mental states.

  10. 10.

    See Husserl (2012), pp. 284–291, for more discussion.

  11. 11.

    We thank the anonymous reviewer for pressing us to clarify this point.

  12. 12.

    Carlos Montemayor and Harry Haladjian, for example, account for the perceptual experience of the duck-rabbit image and of the Necker cube in the following way: “Neither of these shifts in perception entail changes in the object itself. The corresponding images, with their static and objective features, would constitute the icon, while that experienced changes would be characterized in terms of semantic content, attention, and epistemic access to mutually incompatible interpretations of the stimuli” (Montemayor and Haladjian 2015, p. 145).

  13. 13.

    We thank the anonymous reviewer for pressing us to address this problem.

  14. 14.

    What Gurwitsch means by “relevance” is not entirely clear. Chudnoff explains it as a relation of “centrality” and points out how it can be determined in various ways. See Chudnoff (2013), pp. 569–571 for more discussion.

  15. 15.

    Anthony Peressini advances a different interpretation. He argues based on a careful reading of Tononi’s writing that IIT means by “intrinsic” that something is an “observer independent (real) property” (Peressini 2013, 199–200). We admit he is exegetically correct, and so the criticism is effective. But we do not think that this is the idea Tononi actually tried to deliver with this expression. For it is clear from what he writes that he wanted to emphasize how consciousness has a different mode of existence from other objective entities.

  16. 16.

    We thank the anonymous reviewers for pressing us to clarify this point.

  17. 17.

    de Barros et al. (2016) indicates a similar point in terms of the “contextuality” of consciousness. They suggest based on this observation that it may be impossible to make exact calculations of Φ-values, not just as a matter of practical difficulty, but as a matter of mathematical incompatibility between IIT and the mathematical theory of contextuality.

  18. 18.

    We are grateful to the anonymous reviewer for pressing us to be clear on this issue.

  19. 19.

    See Wu (2014) for more discussion.

  20. 20.

    See Montemayor and Haladjian (2015), for a comprehensive overview and a critical discussion of the debate.

  21. 21.

    See Arvidson (2006) for a contemporary discussion on this topic.

  22. 22.

    Chudnoff describes the effect by making a conceptual distinction between two kinds of phenomenal properties, phenomenal content and phenomenal manner (Chudnoff 2013, pp. 565–6). Phenomenal content is determined by the things that are presented in experience, while phenomenal manner concerns the way in which they are presented. On this terminology, the phenomenal content changes in the case of Necker cube, while in the ordinary case of attentional shift, it is only the phenomenal manner in which the content shows up that changes. In contrast, we use the term phenomenal content to describe the totality of what correlates to the subjective act, including both the things presented and the ways in which they are presented, which roughly corresponds to what Chudnoff calls phenomenal character. For the various ways in which conscious experience is modified by attention, see Arvidson (2006), ch.3, and Gurwitsch (1966a), pp. 223–250.

  23. 23.

    However, Dow (2017) criticizes the general characterization of absorbed coping in terms of lack of self-awareness. This amounts to a different way of responding to the objection described in this paragraph.

  24. 24.

    See Oizumi et al. (2014), pp. 3–15 for more detail.

  25. 25.

    As Peressini points out, the claim is only motivated by the observation that both the phenomenal content and the major complex bear an integrated, holistic structure of some sort, which he describes dismissively as “thin stuff on which to ground the [identity] claim” (Peressini 2013, p. 194).

  26. 26.

    This is to say that we are going to read IIT as a theoretical framework that intends to unify phenomenological and neuroscientific accounts of consciousness, an answer to what Lutz and Thompson (2003) calls the “explanatory gap problem”, as opposed to the hard problem of explaining the metaphysical relation between consciousness and physical nature (see Lutz and Thompson 2003, pp. 47–48). We are not alone in adopting such an empirical reading of IIT. For example, Tsuchiya et al. (2016) presumes an empirical interpretation of the central identity to suggest the possibility of testing the proposal by using the mathematical formalism of category theory. Similarly, Yoshimi (2011) suggests, independently of IIT, the possibility of identifying a “supervenience function” that links mathematically the dynamics of brain activity with that of conscious experience.

  27. 27.

    See Bayne et al. (2016) for a critical assessment of the concept of the level of consciousness.

  28. 28.

    We thank the anonymous reviewer for reminding us of this option.

  29. 29.

    How does the distinction made at the phenomenological level between subjective acts and mere subjective attitudes map onto the structure of the physical system? One possibility is that the noetic complex intersects with the major complex when the subjective dimension figures in the phenomenal content at the phenomenological level, while the two complexes do not overlap when the subjective dimension remains outside the phenomenal content.


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The work of KM is supported by JSPS Overseas Research Fellowship (2016-2018), JSPS KAKENHIGrant Number 16K13147 and 18K00032. The work of OW is funded by the Earth-Life Science InstituteOrigins Network (EON) Research Fellow Program, supported by the John Templeton Foundation. KMthanks Hiroaki Hamada, Takuya Niikawa, and Satoshi Nishida for a close examination of the paper in itsearly stage of conception. Earlier versions of the paper have been presented at the Initiative for theSynthesis of the Studies of Awareness (ISSA) Summer School 2017, The Science of Consciousness2017, the Mind and Brain Annual Conference at the Center for Cognition and Neuroethics, and YHouseWorkshop “Opening Up Phenomenology”. We appreciate the audience in each occasion for providing anumber of important feedbacks.

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The paper is a product of an ongoing conversation on the topic between the two authors. Sections 1-5 aresingle-authored by KM, and section 6 is jointly authored by KM and OW. Both authors edited andproofread the entire text, and they have a shared commitment to the content of the paper.

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Correspondence to Katsunori Miyahara.

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Miyahara, K., Witkowski, O. The integrated structure of consciousness: phenomenal content, subjective attitude, and noetic complex. Phenom Cogn Sci 18, 731–758 (2019).

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  • Unity of consciousness
  • Integrated information theory of consciousness
  • Gestalts
  • Holistic integration
  • Aron Gurwitsch
  • Maurice Merleau-Ponty
  • Dynamical systems theory
  • Phenomenology and neuroscience