Owing to the contextuality of the properties of quantum objects, quantum mechanics does not appear to countenance the elision of the thinking and perceiving subject. If quantum objects owe their properties to the experimental conditions in which they are observed, the experimental apparatus cannot owe its properties to the quantum objects of which it is commonly said to be composed. It follows that neither quantum objects nor measuring instruments can be regarded as property-carriers existing independently of conscious subjects. However, if the difference between the classical domain and the quantum domain is understood as essentially the difference between the manifested world and what is instrumental in its manifestation, the elision of the subject can again be achieved.
Owing to the contextuality of the properties of quantum objects, quantum mechanics does not appear to countenance the elision of the thinking and perceiving subject. If quantum objects owe their properties to the experimental conditions in which they are observed, the experimental apparatus cannot owe its properties to the quantum objects of which it is commonly said to be composed. It follows that neither quantum objects nor measuring instruments can be regarded as property-carriers existing independently of conscious subjects. However, if the difference between the classical domain and the quantum domain is understood as essentially the difference between the manifested world and what is instrumental in its manifestation, the elision of the subject can again be achieved.
What does not satisfy me in that theory [quantum mechanics], from the standpoint of principle, is its attitude towards that which appears to me to be the programmatic aim of all physics: the complete description of any (individual) real situation (as it supposedly exists irrespective of any act of observation or substantiation). Albert Einstein, Reply to Criticisms [This] implies the impossibility of any sharp separation between the behaviour of atomic objects and the interaction with the measuring instruments which serve to define the conditions under which the phenomena appear . In fact, the individuality of the typical quantum effects finds its proper expression in the circumstance that any attempt of subdividing the phenomena will demand a change in the experimental arrangement introducing new possibilities of interaction between objects and measuring instruments which in principle cannot be controlled. Consequently, evidence obtained under different experimental conditions cannot be comprehended within a single picture, but must be regarded as complementary in the sense that only the totality of the phenomena exhausts the possible information about the objects. Indeed the finite interaction between object and measuring agencies conditioned by the very existence of the quantum of action entails – because of the impossibility of controlling the reaction of the object on the measuring instruments, if these are to serve their purpose – the necessity of a final renunciation of the classical idea of causality and a radical revision of our attitude towards the problem of physical reality. […]
Knowing the mutual interconnection of everything with everything, it is no problem to interpret the interactions between the measuring and quantum systems as any other interactions between two or more systems consisting of elementary quantum dipoles. So, all relations between the measuring apparatus and measured quantum objects are only parts of the universal cosmic network of elementary quantum interactions creating the objective physical reality, independent of a human consciousness. But the observer, as a conscious subject, plays an active and creative role in his communication with the micro-world.
After a summary of Bohr's views and their relation to Kant's theory of science, two fruitless lines of attack on the measurement problem are discussed: the way of the psi-ontologist and the way of the QBist. In the remainder of the paper the following results are obtained. (i) Because the testable correlations between outcomes of measurements of macroscopic positions are consistent with both the classical and the quantum laws, there is no conflict between the superposition principle and the existence of measurement outcomes. (ii) Intrinsically, each fundamental particle is numerically identical with every other fundamental particle. What presents itself here and now with these properties and what presents itself there and then with those properties is one and the same entity, herein called "Being." (iii) The distinction between a classical domain and a quantum domain is essentially a distinction between the manifested world and its manifestation. By entering into reflexive spatial relations, Being gives rise to (a) what looks like a multiplicity of relata if the reflexive quality of the relations is ignored, and (b) what looks like a substantial expanse if the spatial quality of the relations is reified. (iv) The reason why quantum mechanics is a calculus of correlations between measurement outcomes is that it concerns the progressive realization of distinguishable objects and distinguishable regions of space. (v) The key to the relation between quantum mechanics and experience is that Being does not simply manifest the world, Being manifests the world to itself. It is at once the single substance by which the world exists and the ultimate self or subject for which it exists. The question how we are related to this ultimate self or subject is discussed.
In resisting attempts to explain the unity of a whole in terms of a multiplicity of interacting parts, quantum mechanics calls for an explanatory concept that proceeds in the opposite direction: from unity to multiplicity. Being part of the Scientific Image of the world, the theory concerns the process by which (the physical aspect of) what Sellars called the Manifest Image of the world comes into being. This process consists in the progressive differentiation of an intrinsically undifferentiated entity. By entering into reflexive spatial relations, this entity gives rise to (i) what looks like a multiplicity of relata if the reflexive quality of the relations is not taken into account, and (ii) what looks like a substantial expanse if the spatial quality of the relations is reified. If there is a distinctly quantum domain, it is a non-spatial and non-temporal dimension across which the transition from the unity of this entity to the multiplicity of the world takes place. Instead of being constituents of the physical world, subatomic particles, atoms, and molecules are instrumental in its manifestation. These conclusions are based on the following interpretive principle and its more direct consequences: whenever the calculation of probabilities calls for the addition of amplitudes, the distinctions we make between the alternatives lack objective reality. Applied to alternatives involving distinctions between regions of space, this principle implies that, owing to the indefiniteness of positions, the spatiotemporal differentiation of the physical world is incomplete: the existence of a real-valued spatiotemporal background is an unrealistic idealization. This guarantees the existence of observables whose values are real per se, as against “real by virtue of being indicated by the values of observables that are real per se.” Applied to alternatives involving distinctions between things, it implies that, intrinsically, all fundamental particles are numerically identical and thus identifiable with the aforementioned undifferentiated entity.
Quantum phenomena seem to blur the distinction between matter and information, and objectivity and subjectivity. A quantum particle cannot be observed directly and needs to be 'observed' in a suitably designed measurement experiment. Even in such an experiment, what we actually observe (by means of senses) is the measuring device, which is said to be ‘classical’. The position and other 'observable' properties of a quantum particle (QP) are only inferred from the devices’ readings. Quantum Mechanics tells us that a QP is a packet of de Broglie's phase waves, each of which carries no energy and goes faster than light. Clearly, the phase wave is a mathematical abstraction, an idea in physicists' minds; it cannot be observed for example, like light, or heard like a wave of an oscillating string. However, the phase wave’s wavelength can be measured in a suitably designed experiment. So, one may call the de Broglie phase wave as a piece of ‘objective information’! Since classical matter, i.e., matter which is observable directly by senses is supposed to be made of numerous QPs also, it seems that all matter is made of ‘objective information’, i.e., information, which is not observable directly but some of whose properties can be measured and verified in some way and agreed upon by a group of people. Considering the brain to be a quantum system, we will explain why a sensory experience is both objective and subjective at the same time whereas other conscious experiences such as those of emotions and judgments are subjective but not objective. For this purpose, we note the neuroscience finding that it is necessary and sufficient that one’s brain (a quantum system) builds a neural record which is a faithful representation of the sensory input it receives from the outside world, for one to have the corresponding conscious sensory experience.
The assumption of an objective world underlying all our experiences is deeply embedded in our everyday thinking and in our language, and has been an unquestioned presupposition of the scientific enterprise for at least four centuries. Yet it is well known that quantum physics raises some highly problematic questions in this respect, questions that are still open, almost a century from the inception of the theory. I would like to propose that these questions stem from deep philosophical assumptions and can be answered in a much more coherent way if we understand the notion of an objective world not as a primary reality, but as an emergent aspect of a primary process that can be described as “experiencing”. A coherent description of the appearance of an objective world in the process of experiencing relies on a certain understanding of what is technically known as the “quantum measurement problem”, i.e. the description of the process of observation in quantum physics, which is the key problematic aspect of the theory. I will propose that the basic features that characterize a quantum observation have a much wider scope, and describe in fact all acquisition of information by an “embodied observer”, in short all experiencing happening in the world. By applying to this larger context work I have done in the more technical frame of the quantum measurement problem it can be shown that the nature of the process of experiencing is such as to inevitably generate the appearance of an objective world. Thus the objectivity of the world, although not primary and ultimately real, is an intrinsic consequence of our “experiential embodiment”, i.e. of the fact that we are in the world and all our experiences correspond to physical happenings in the world. When examined in this perspective, the “paradoxes” of quantum physics are an invitation to abandon the metaphysical assumption of the primacy of the objective dimension of reality. A philosophical position much more in tune with quantum physics views the process of experiencing as the primary source of both subject and object, consciousness and world.