Michel Bitbol

Open peer commentary on the article “Never Mind the Gap: Neurophenomenology, Radical Enactivism, and the Hard Problem of Consciousness” by Michael D. Kirchhoff & Daniel D. Hutto. Upshot: We point out that the significance of the neurophenomenological approach to the “hard problem” of consciousness is underrated and misunderstood by the authors of the target article. In its original version, neurophenomenology implies nothing less than a change in our own being to dispel the mere sense that there is a problem to be theoretically solved or dissolved. Neurophenomenology thus turns out to be much more radical than the enactivist kind of dissolution promoted by the authors.

The so-called paradoxes of quantum physics are easily disposed of as soon as one accepts that there are no such things as intrinsically existing particles and their intrinsic properties, but that both particles and properties are relational “observables.” Accordingly, quantum physics does not offer a “description of the outer world,” but rather a prescription about how to make probabilistic predictions within a participatory environment. The latter view looks quite radical with respect to standard Western Aristotelian ontology; but it looks natural in the context of the Indian-Buddhist concept of Pratītyasamutpāda which underpins Śūnyatā. Special attention will then be devoted to the quantum feature of non-separability, which displays remarkable similarities with Pratītyasamutpāda. Finally, the meaning of such twofold parallel between quantum physics and Śūnyatā will be discussed. This parallel will be related to the similarity of epistemological situation between knowing a world from which we are not entirely separated and knowing oneself.

In physics, structures are good candidates for the role of transparadigmatic invariants, which entities can no longer play. This is why structural realism looks more credible than standard entity realism. But why should structures be stable, rather than entities? Here, structural realists have no answer ; they content themselves with the mere observation that this is how things stand. By contrast, transcendental structuralism can easily make sense of this fact. Indeed, it shows that when knowledge bears on phenomena, namely on the emergent byproduct of a relation between the explorer and what is to be explored, this knowledge necessarily bears on relations between such phenomena. After a development on the clarifying power of transcendental structuralism, I turn to an early transcendental structuralist interpretation of quantum mechanics proposed by Jean-Louis Destouches. Destouches, an early French philosopher of physics, was a student of Louis de Broglie. He recasted in the 1940 the very concept of physical theory in the light of quantum physics. According to him, whenever phenomena are inextricably relative to the experimental set-up, a physical theory cannot provide anything beyond a list of interconnected predictions for future facts given a relevant class of past facts. In his general mathematical theory of predictions, the Ψ-functions of quantum mechanics do not refer to some “real” waves; they are shown to be nothing but the formal expression of the phenomena’s being relative to incompatible experimental contexts. Since the quantization of variables can itself be derived from a wave-mechanical formalism, it becomes clear that the most prominent features of quantum mechanics are a mere consequence of contextuality. Destouches thus proved that it is easy to make sense of quantum mechanics provided a reflective attitude is adopted. By contrast, too many difficulties arise when one tries at any cost to make quantum mechanics intelligible within a purely ontological framework.

This article aims at reducing the gap between mathematics and physics from a Wittgensteinian point of view. This gap is usually characterized by two discriminating features. The propositions of physics assert something which might be false; they have a hypothetical character. On the contrary, since mathematical propositions are rules that condition the form of assertions, they remain immune from falsification. The propositions of physics refer to facts that may confirm or refute them. On the contrary, since mathematical propositions have no meaning independently of the demonstration procedures, it cannot be said that they refer to “facts” that pre-exist demonstrations. If we take a closer look, however, these two differences fade away. On the one hand, the propositions of physics are more resistant to experimental tests than has been said in the wake of logical positivism. On the other hand, the “factual” empirical material is defined and co-constituted by instruments whose arrangement is determined by the theory to be tested. I conclude by discussing the possibility of a Wittgensteinian philosophy of contemporary physics.

On distingue trois strates interdépendantes dans les paradigmes kuhniens : le savoir-faire expérimental, le formalisme, et les engagements ontologiques. Seul le niveau ontologique se trouve intégralement et explicitement exprimé dans le cadre du langage courant. Il semble donc qu’assimiler l’« incommensurabilité » des paradigmes à une intraductibilité revient à esquiver une partie du problème. Afin de compenser cette apparente incomplétude, une conception néo-pragmatiste et structuraliste de la physique est développée, en l’appuyant sur les réflexions d’A. Pickering et I. Hacking. Au lieu d’être marginalisé, le domaine des pratiques devient dans cette conception l’axe central où se définissent toutes les composantes de la connaissance, et où se décident toutes les questions, y compris celle de l’incommensurabilité.

Décio Krause has achieved a thorough reconstruction of logic and set theory, to account for the unusual objects or quasi-objects of quantum physics. How can one cope with the (partial) lack of criteria of individualization and re-identification of quantum objects, when the elementary operations of counting them, and constituting sets of them, are to be performed? Here, I advocate an alternative strategy, that consists in going below the level of logic and set theory to inquire how their categories are generated in the experience and activity of knowing subjects, and whether this mode of category generation is still relevant in the field of experimental quantum physics. This project of a “genealogy of logic” is borrowed from Husserl’s last treatise, entitled Experience and Judgment. It is transposed to the case of quantum physics by way of a QBist approach of Mott’s theorization of quasi-“trajectories” in Wilson cloud chambers. It is also shown that one of the most appropriate ontologies for quantum objects or quasi-objects involves reversing the (grammatical) roles of subject and predicate, as advocated by Japanese philosopher Nishida Kitarô in reasonable agreement with both Schrödinger’s and Krause’s approaches of the concept of “particle”.

According to Husserl, the epochè (or suspension of judgment) must be left incomplete. It is to be performed step by step, thus defining various layers of “reduction.” In phenomenology at least two such layers can be distinguished: the life-world reduction, and the transcendental reduction. Quantum physics was born from a particular variety of the life-world reduction: reduction to observables according to Heisenberg, and reduction to classical-like properties of experimental devices according to Bohr. But QBism has challenged this limited version of the phenomenological reduction advocated by the Copenhagen interpretation. QBists claim that quantum states are “expectations about experiences of pointer readings,” rather than expectations about pointer positions. Their focus on lived experience, not just on macroscopic variables, is tantamount to performing the transcendental reduction instead of stopping at the relatively superficial layer of the life-world reduction. I will show that quantum physics indeed gives us several reasons to go the whole way down to the deepest variety of phenomenological reduction, may be even farther than the standard QBist view: not only reduction to experience, or to “pure consciousness,” but also reduction to the “living present.”

Open peer commentary on the article “Enaction as a Lived Experience: Towards a Radical Neurophenomenology” by Claire Petitmengin. Upshot: Petitmengin’s strategy of dissolution of the “hard problem” of consciousness is shown to rely on some radical phenomenological premises that are listed and analyzed. It presupposes a starting point of research in a state of epoché ; it unfolds into a participatory conception of truth; and it ends in a quest for non-dual pristine experience. Each one of these moves is endorsed and amplified.

The article by Froese, Gould and Seth is a survey rather than a commentary, dealing with the intertwined issues of the validity of first- person reports and of their interest for a science of consciousness. While acknowledging that experiential research has already produced promising results, the authors find that it has not yet produced 'killer experiments' providing a definitively positive answer to these two questions, and wonder what kind of experiment would allow it. Our response will address these two questions successively

In its most radical version, Neurophenomenology asks researchers to suspend the quest of an objective solution to the problem of the origin of subjectivity, and clarify instead how objectification can be obtained out of the coordination of subjective experiences. It therefore invites researchers to develop their inquiry about subjective experience with the same determination as their objective inquiry. However, accessing lived experience raises the question of the investigation method, and of the reliability of its results. Here, we present an accurate method of exploration of lived experience: the elicitation (or microphenomenological) interview. In the course of this interview, one first triggers a form of “phenomenological reduction”, then assists the subject in retrieving or “evoking” past experiences, and finally helps the subject to perform acts of attention about this evoked experience, to describe it faithfully. It is shown that this method addresses a set of traditional objections against introspection.

Toute science, admet-on, commence par détacher un objet en le rendant indépendant des sujets et des situations. Mais cette conception étroite de la connaissance scientifique laisse subsister des zones d'ombre. La conscience n'est pas un objet. Elle est ce sans quoi rien ne pourrait être pris pour objet. La conscience n'est pas détachable des sujets, car elle s'identifie à ce qui est vécu par un sujet. De façon analogue, en physique quantique, un phénomène n'est pas dissociable de son contexte expérimental, car il s'identifie à ce qui se manifeste à grande échelle au laboratoire. Que faire pour ne pas laisser ces cas extrêmes de côté? Généraliser la méthode scientifique. Ne plus la borner à définir et à caractériser des objets, mais l'étendre à la coordination directe des expériences. Telle est la révolution de pensée qu'il faut accomplir pour résoudre, ou plutôt dissoudre, deux questions-limites de la science : le problème de l'origine de la conscience et le paradoxe du "chat de Schrödinger" en physique quantique.

On distingue trois strates interdépendantes dans les paradigmes kuhniens : le savoir-faire expérimental, le formalisme, et les engagements ontologiques. Seul le niveau ontologique se trouve intégralement et explicitement exprimé dans le cadre du langage courant. Il semble donc qu’assimiler l’« incommensurabilité » des paradigmes à une intraductibilité revient à esquiver une partie du problème. Afin de compenser cette apparente incomplétude, une conception néo-pragmatiste et structuraliste de la physique est développée, en l’appuyant sur les réflexions d’A. Pickering et I. Hacking. Au lieu d’être marginalisé, le domaine des pratiques devient dans cette conception l’axe central où se définissent toutes les composantes de la connaissance, et où se décident toutes les questions, y compris celle de l’incommensurabilité.

Le présent tome traite de la mécanique quantique non relativiste. Il comprend, outre ses fondements, de multiples applications de la mécanique quantique dans une plus large mesure que dans les cours généraux. Dans leur exposé des questions générales, les auteurs dégagent au maximum l'essence physique de la théorie, à partir de laquelle ils développent l'appareil mathématique. Contrairement au schéma habituel allant des théorèmes mathématiques relatifs aux opérateurs linéaires, les auteurs déduisent les exigences mathématiques auxquelles doivent répondre les opérateurs et les fonctions propres à partir de la position physique du problème. Des compléments mathématiques sont donnés en appendice.

Ce livre renouvelle le débat séculaire sur la possibilité de réduire la conscience à un processus neuronal. Il fait du lecteur l'arbitre de l'enquête, non seulement en tant que spectateur rationnel, mais aussi en tant qu'acteur apte à se reconnaître conscient aux moments décisifs de l'argumentation. Le fin mot de l'énigme ne se dissimulerait-il pas dans l'évidence que la question sur l'origine de la conscience a une conscience pour origine? Au cours de cette investigation qui mobilise la phénoménologie, la métaphysique, les pratiques contemplatives, les neurosciences et la théorie de l'évolution, chaque thèse sur la conscience est alors mise à l'épreuve d'un questionnement lancinant : pour qui vaut-elle et dans quel état de conscience doit-on être pour la soutenir? L'objectif n'est pas d'opposer entre elles les doctrines (physicaliste ou dualiste), les stratégies de recherche (objective ou réflexive) et les directions d'étude (physiologique ou introspective), mais de les rapporter aux postures existentielles divergentes d'où elles tirent leur pouvoir de persuasion. Une réflexion singulière sur et au coeur de la conscience.