This paper differs from any previous view in discussing quantum pure possibilities as individuals, existing independently of any observer or mind. These pure possibilities are also absolutely independent of any metaphysical or logical view that endorses the notion of possible worlds. In my view, the relationship between quantum possibilities and classical physical reality is not between reality as such, as it is in itself, and its phenomena. It is rather between fundamental or primary reality, consisting of quantum pure possibilities, on the one hand, and its actualization in what classical physics has discovered so far, on the other. As individual pure possibilities, quantum entities must be, at least ontologically, distinct and different from one another, regardless of the epistemological standing of quantum physics. Hence, quantum metaphysics is committed to the principle of the identity of indiscernibles. Finally, I analyze the two-slit experiment, interference, and entanglement in the light of my approach.
This paper differs from any previous view in discussing quantum pure possibilities as individuals, existing independently of any observer or mind. These pure possibilities are also absolutely independent of any metaphysical or logical view that endorses the notion of possible worlds. In my view, the relationship between quantum possibilities and classical physical reality is not between reality as such, as it is in itself, and its phenomena. It is rather between fundamental or primary reality, consisting of quantum pure possibilities, on the one hand, and its actualization in what classical physics has discovered so far, on the other. As individual pure possibilities, quantum entities must be, at least ontologically, distinct and different from one another, regardless of the epistemological standing of quantum physics. Hence, quantum metaphysics is committed to the principle of the identity of indiscernibles. Finally, I analyze the two-slit experiment, interference, and entanglement in the light of my approach.
The notion of an individual and the related issues on individuation are topics that appear in the philosophical discussion ever since the antiquity. The idea of an individual thing is intuitively clear: an individual is something of a specific kind that is a unity, having its own identity, and being so that it is possible at least in principle to discern it from any other individual, even of similar species. But when we try to leave the intuitive realm and push this idea to a logical analysis, we find a cluster of problems that are difficult to overcome within standard logico-mathematical contexts. In this work, we shall be concerned with some aspects of this intuitive concept of an individual and on some related facts about individuation taken from recent discussions that arose ever since the inception of quantum theory, pushing the discussion to a “logical” view, which in our opinion is still lacking in the usual debates on such issues. In the final part of the paper, we propose a metaphysics where the notion of identity is substituted, for some objects, by a weaker notion of indiscernibility, and we try to justify such a move. In most of the uses of the expression “quantum theory”, we shall not make explicit the distinction between the non-relativistic and the relativistic approaches, although they of course are quite different, for we think that the problems as we shall present them appear in both versions. But, as the text goes, the context will distinguish between them and these questions will become clear to the reader.
Quantum physics, in contrast to classical physics, allows non-locality and indeterminism in nature. Moreover, the role of the observer seems indispensable in quantum physics. In fact, quantum physics, unlike classical physics, suggests a metaphysics that is not physicalism (which is today’s official metaphysical doctrine). As is well known, physicalism implies a reductive position in the philosophy of mind, specifically in its two core areas, the philosophy of consciousness and the philosophy of action. Quantum physics, in contrast, is compatible with psychological non-reductionism, and actually seems to support it. The essays in this book explore, from various points of view, the possibilities of basing a non-reductive philosophy of mind on quantum physics. In doing so, they not only engage with the ontological and epistemological aspects of the question but also with the neurophysiological ones.
Several experiments have suggested that the complete indistinguishability of quantum systems is to be considered a real phenomenon. Experiments such as the HOM effect, the existence of BECs, the path identity cases, and many others are physical realities of today. Physicists `explain’ these phenomena using different models, such as Bohmian mechanics, relational quantum mechanics or the QBism approach. Most of these models are constructed within a standard mathematical framework, meaning standard mathematics, where all things can, even if only in principle, be distinguished from one another, so complete indistinguishability can only be mimicked. These approaches may work for physical purposes but are debatable regarding logical and metaphysical questions. If we accept that such questions are at least part of the philosophical aspect of quantum physics, then we are authorised to analyse them and try to offer an alternative. Looking for an alternative, we consider Alain Aspect’s and Anton Zeilinger’s views about quantum realism, opting for Aspect’s acceptance of some kind of reality behind the wave-function, while Zeilinger suggests that everything comes from information. In our opinion, the case is the opposite: it is information that comes from the existence of things. The aim of this paper is to justify why we think that the underlying reality (in Aspect’s sense) can be seen as a quantum ontology of non-individuals.
The topics of identity, individuality and indiscernibility had already entered the domain of the philosophy of physics, mainly in what respects the philosophy of quantum theories. In this paper, I present the main ideas of an underlying metaphysics that considers the basic entities of quantum physics as non-individuals, that is, as entities to which the standard theory of identity of classical logic and standard mathematics (set theory) does not apply. Two things must be emphasized: the first is that we pursue Erwin Schrödinger’s ideas that the notion of identity (or sameness ) does not apply to quantum things; the second is to follow Heinz Post’s claim that the non-individuality of quantum entities ‘must be introduced right at the start’ and not by taking individuals and making them pretend to be non-individuals ‘by hand’, say by confining them to non-rigid structures. Thus, this paper should be regarded as an attempt to justify the metaphysics of non-individuals and the logical systems that cope with them, although these systems are here only referred to. We also answer some criticisms that have been directed to such a view. The paper is directed to an audience of both physicists interested in foundations and philosophers of physics. This article is part of the theme issue ‘Identity, individuality and indistinguishability in physics and mathematics’.
One recent debate in philosophy of physics has centered whether quantum particles are individuals or not. The received view is that particles are not individuals and the standard methodology is to approach the question via the structure of quantum theory. I challenge both the received view and the standard methodology. I contend not only that the structure of quantum theory is not the right place to look for conditions of individuality that quantum particles may or may not satisfy, but also that there is an important role for traditional metaphysics to play. Consequently, my work brings together the philosophy of physics and traditional metaphysics literatures to shed new light on the debate over the individuality of quantum particles. I defend a set of conditions of individuality and argue that quantum particles satisfy these conditions thereby defending the view that particles are individuals in opposition to the received view. I also challenge a second feature of the standard methodology insofar as I challenge the significance of the Principle of the Identity of Indiscernibles in terms of which much discussion in the philosophy of physics literature is framed. My work is significant in a number of additional ways as well. My work implies that the dominant explanation for quantum statistics in terms of non-individuality is incorrect and it also undermines the ontic-structural realists metaphysical underdetermination challenge to the scientific realist.
The aim of this paper is to discuss some of the main philosophical and metaphysical implications of quantum physics, especially those which concern the issues of epistemic humility and ontological realism. My thesis is that the impossibility of reaching an objective knowledge of nature does not imply the renunciation of ontological realism, but rather encourages scientists to adopt an attitude of epistemic humility. The argument firstly presents the main theories of quantum physics currently discussed, focusing on the measurement problem and its ontological implications. Afterwords, the issues of objectivity and realism are properly addressed. In the end, we discuss statistics as the new form of scientific epistemology, along with the concept of potentiality as the fundamental category of quantum metaphysics. Throughout, we establish some parallelisms between quantum physics theories and theology to show that, when human beings investigate the foundations of reality, some thought patterns, some core problems, and some possible solutions resemble one another, regardless of the specific perspective and language with which they are formulated.