Niccolò Covoni

This paper examines the role of perspectivism in Relational Quantum Mechanics, situating it within the broader landscape of quantum interpretations and the scientific realism debate. We argue that, while interpretations such as QBism embrace strong forms of perspectivism, Relational Quantum Mechanics adopts a “soft” perspectivism, limiting the observer’s role to selecting experimental contexts without compromising its realist framework. We also explore the historical roots of Relational Quantum Mechanics, showing that relational ideas in the works of Bohr and other pioneers similarly avoided strong perspectivist commitments. By analyzing both contemporary and historical perspectives, we argue that Relational Quantum Mechanics offers a minimalist yet robust relational interpretation, distinct from more subjectivist approaches.

This paper argues that von Neumann entropy plays two conceptually distinct roles in quantum theory. When applied to global mixed states, it expresses the quantum analogue of the informational entropy. But when applied to reduced states of entangled systems, it measures objective physical correlations. We propose that this second usage realizes a new informational kind, which we call relational information. Unlike information in communication theory, it reflects structural interdependence between systems, not probability about a certain outcome. We further suggest that this informational kind has ontological significance: relational information is a physically instantiated feature of entangled systems, and not merely an agent-relative concept.

This text will perhaps only be understood by those who have themselves already thought the thoughts which are expressed in it, or similar thoughts. Its meaning could be summed up somewhat as follows: whatever can be said at all, can be said clearly by any speaker who is part of the world that is spoken about, and who speaks from its perspective. \noindent Of course others far better than us have already been around here. But we feel some details have been left out, which quantum phenomena have brought into sharp light, and these bring further clarity. Whoever understands us recognizes again the following propositions as senseless. After climbing through these, over them so to speak, will kick away the ladder, once more. Thanks to this futility, we feel shamelessly entitled to parrot a Master. Inspired not by his preaching but rather by his example (and not in small part by its later reflections), we have written all this, as we actually think that not to remain silent, even whereof one cannot speak, is not such a bad idea after all, maybe only, as we learned from him, to keep the warning alive that there are questions that have no meaning. What we hold onto is not knowledge of an absolute order, but the fleeting grasp of a perspective on perspectives. Hence this is at most just a manifesto for a picture of the world suggested by quantum mechanics. Each proposition attempts to show a possible way of formulating questions about nature in a manner coherent with what we have recently learned about it. A manner aware of its own partiality. Good philosophy, seems to us, dismantles idols, rather than creating them, and, like a gentle friend, reminds us with indirect hints, over and over again, that the answer to the riddle is that there is no riddle.

The paper addresses the main meta-metaphysical question, i.e., whether it is possible to do metaphysics and, in the case of an affirmative answer, how should we do it? With such an aim in mind, we sketch the broad context in which these meta-metaphysical questions arose in the philosophical literature (§ 1); then, we present what we take to be the three most widespread conceptions of metaphysics that are available in the analytic tradition: the neo-Quinean (§ 2), metaphysics as the science of possibilities (§ 3) and metaphysics as the study of the fundamental structures of reality (§ 4). We criticise these positions throughout these paragraphs before cashing out our proposal (§ 5). Our interpretation aligns with the recently proposed approach known as ‘naturalised metaphysics’ but with crucial differences. In our view, metaphysics is not only constrained by physics; rather, it grows out from all empirical sciences. More precisely, it can be achieved using formal language and the analysis of the results of scientific theories.

Evandro Agazzi hat die Möglichkeit einer Versöhnung zwischen dem logischen Empirismus und dem Realismus aufgezeigt, indem er sein Konzept der wissenschaftlichen Objektivität vorschlug, das den Begriff der Entität durch den des Objekts ersetzt, das als strukturierte Menge von Eigenschaften verstanden wird. Diese Konzeption wurde einerseits aus einer eher empiristischen Perspektive entwickelt, der zufolge die Realität des Objekts auf eine seiner vorhersagbaren Eigenschaften verlagert wird, und hat andererseits seine fruchtbare Kritik an der orthodoxen Interpretation der Quantenmechanik und seine Forderung nach einer realistischen Interpretation hervorgebracht, die auf der Einführung neuer nicht-klassischer Konzepte beruht.