Michel Bitbol

According to Husserl, the epochè 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.”

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.

A phenomenological view of contemplative disciplines is presented. However, studying mindfulness by phenomenology is at odds with both neurobiological and anthropological approaches. It involves the first-person standpoint, the openness of being-in-the-world, the umwelt of the meditator, instead of assessing her neural processes and behaviors from a neutral, distanced, third-person standpoint. It then turns out that phenomenology cannot produce a discourse about mindfulness. Phenomenology rather induces a cross-fertilization between the state of mindfulness and its own methods of mental cultivation. A comparison between the epochè, the phenomenological reduction, and the practice of mindfulness, is then undertaken.

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.

Emergence is interpreted in a non-dualist framework of thought. No metaphysical distinction between the higher and basic levels of organization is supposed, but only a duality of modes of access. Moreover, these modes of access are not construed as mere ways of revealing intrinsic patterns of organization: They are supposed to be constitutive of them, in Kant’s sense. The emergent levels of organization, and the inter-level causations as well, are therefore neither illusory nor ontologically real: They are objective in the sense of transcendental epistemology. This neo-Kantian approach defuses several paradoxes associated with the concept of downward causation, and enables one to make good sense of it independently of any prejudice about the existence (or inexistence) of a hierarchy of levels of being.

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.

Context: At the conference “The Ethical Meaning of Francisco Varela’s Thought,” which took place on 28 May 2011 in Sassari, Italy, Humberto Maturana, Michel Bitbol, and Pier Luigi Luisi participated in two discussions. Purpose: In this edited transcription of the discussions, the participants talk about several aspects of autopoiesis, the observer, ontology, making distinctions and distinguishing different domains, perception and illusion, and transcendence. Results: The discussions shed light on how constructivist concepts are perceived by individual authors. Concepts such as “transcendence” and “objectivity” are understood in different ways. Constructivist content: The concepts discussed are highly relevant for constructivist approaches

Six arguments against the view that conscious experience derives from a material basis are reviewed. These arguments arise from epistemology, phenomenology, neuropsychology, and philosophy of quantum mechanics. It turns out that any attempt at proving that conscious experience is ontologically secondary to material objects both fails and brings out its methodological and existential primacy. No alternative metaphysical view is espoused (not even a variety of Spinoza’s attractive double-aspect theory). Instead, an alternative stance, inspired from F. Varela’s neurophenomenology is advocated. This unfamiliar stance involves (i) a complete redefinition of the boundary between unquestioned assumptions and relevant questions ; (ii) a descent towards the common ground of the statements of phenomenology and objective natural science : a practice motivated by the quest of an expanding circle of intersubjective agreement.

The formal time symmetry of the quantum measurement process is extensively discussed. Then, the origin of the alleged association between a fixed temporal direction and quantum measurements is investigated. It is shown that some features of such an association might arise from epistemological rather than purely physical assumptions. In particular, it is brought out that a sequence of statements bearing on quantum measurements may display intrinsic asymmetric properties, irrespective of the location of corresponding measurements in time t of the Schrodinger equation. The situation of an observer performing two measurements in two opposite directions of t is eventually investigated. Essential differences are found between two descriptions of this situation: the internal one (taking only into account what is recorded in the observer's memory) and the external one (whereby the observer is considered as a quantum system ruled by the Schrodinger equation). Finally, a method allowing several observers to establish a correspondence between their memory sizes is analyzed. The most important facts that usually lead to the associating of a preferential temporal direction with quantum measurements may be inferred from this correspondence.

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.

Quantum Mechanics has imposed strain on traditional (dualist and representationalist) epistemological conceptions. An alternative was offered by Bohr and Heisenberg, according to whom natural science does not describe nature, but rather the interplay between nature and ourselves. But this was only a suggestion. In this paper, a systematic development of the Bohr-Heisenberg conception is outlined, by way of a comparison with the modern self-organizational theories of cognition. It is shown that a perfectly consistent non-representationalist (and/or relational) reading of quantum mechanics can be reached thus.

This paper analyzes how conflicts of perspective are resolved in the field of the human sciences. Examples of such conflicts are the duality between the actor and spectator standpoints, or the duality of participancy between a form of social life and a socio-anthropological study of it. This type of duality look irreducible, because the conflicting positions express incompatible interests. Yet, the claim of incommensurability is excessive. There exists a level of mental activity at which dialogue and resolution are possible. Reaching this level only implies that one comes back to a state of undetermination between situations and interests whose best model is a superposition of states in generalized quantum theory. Some applications of this strategy of going back below the point of state reduction, from the psychology of perception to the history of civilization, are presented.

When he formulated the program of neurophenomenology, Francisco Varela suggested a balanced methodological dissolution of the hard problem of consciousness. I show that his dissolution is a paradigm which imposes itself onto seemingly opposite views, including materialist approaches. I also point out that Varela's revolutionary epistemological ideas are gaining wider acceptance as a side effect of a recent controversy between hermeneutists and eliminativists. Finally, I emphasize a structural parallel between the science of consciousness and the distinctive features of quantum mechanics. This parallel, together with the former convergences, point towards the common origin of the main puzzles of both quantum mechanics and the philosophy of mind: neglect of the constitutive blindspot of objective knowledge.

In his book _The Empirical Stance_, Bas van Fraassen develops a strong and subtle attack on materialism. This chapter amplifies this criticism from a mainly neo-Kantian standpoint, and identifies by contrast some reasons why van Fraassen tends to baulk at the ultimate consequences of his contest. It first reviews van Fraassen's construal of materialism as a _stance_, and examines some motives many thinkers have to resist this idea. It goes on to describe the drifting conceptions of ‘matter’ according to materialists, and states two motives to be less indulgent than van Fraassen for the particulate conception of matter. The chapter then documents the first motive: loss of the basic cognitive conditions that would enable the particulate conception of matter to provide us with a coherent and unified representation. It also examines a general criterion of materiality, beyond the circular statement that matter is composed of material particles: matter must be both objective and able to manifest itself in space-time. The chapter then applies this criterion and finds difficulties on both sides of the Cartesian divide. It then states a meta-value (progressiveness, open-mindedness) that is shared by materialists to a certain extent, but shows that both empiricism and neo-Kantianism fare better with respect to this meta-value. Finally some limitations in van Fraassen's position that prevent him from offering a far enough reaching critique of materialism are presented.

The reduction of the concept of heat to that of molecular kinetic energy is recurrently presented as lending analogical support to the project of reduction of phenomenal concepts to physical concepts. The claimed analogy draws on the way the use of the concept of heat is attached to the experience in first person of a certain sensation. The reduction of this concept seems to prove the possibility to reduce discourse involving phenomenal concepts to a scientific description of neural activity. But is this analogy really justified? We will show that if there is an analogy, far from speaking for a reduction of phenomenal concepts, it rather stresses the necessity to integrate phenomenal reports in the scientific study of experience.