Abstract Quantum modal realism is a strange and unfamiliar doctrine. That is not by itself a reason to disbelieve it. Physical reality has continually turned out to be larger than we imagined possible; quantum modal realism expands reality one step further, beyond the actual world. In this short conclusion, I trace the history of human beliefs about the size of the cosmos, and compare the expansion of our horizons that results from quantum modal realism to previous revolutions in cosmology. I also observe that in some ways quantum modal realism is economical; while it may expand our conception of reality, it does not expand our conception of what is possible or of what is actual.
Abstract Quantum modal realism is a strange and unfamiliar doctrine. That is not by itself a reason to disbelieve it. Physical reality has continually turned out to be larger than we imagined possible; quantum modal realism expands reality one step further, beyond the actual world. In this short conclusion, I trace the history of human beliefs about the size of the cosmos, and compare the expansion of our horizons that results from quantum modal realism to previous revolutions in cosmology. I also observe that in some ways quantum modal realism is economical; while it may expand our conception of reality, it does not expand our conception of what is possible or of what is actual.
Quantum physics can be understood as an epistemological rupture that transforms the foundations of modern scientific rationality. In contrast to the Newtonian mechanistic worldview that underpinned universalist notions of progress, objectivity, and control, quantum mechanics introduces uncertainty, contextuality, non-locality, and the constitutive role of observation into scientific knowledge. These features destabilize the image of reality as a unified, hierarchically structured, and fully transparent domain, thereby challenging the epistemic premises of Western universalism. At the cultural level, this rupture finds expression in forms of scientific magical realism, where the quantum world appears as strange, paradoxical, elusive and fundamentally ungraspable. Such representations allow the quantum revolution to be interpreted not only as a theoretical breakthrough in physics but as an internal epistemological transformation of modern rationality itself. The issue is not the abandonment of rationality, but the reconfiguration of its foundations: the acknowledgment of uncertainty, contextuality, and the participatory role of the observer as structural features of knowledge. This shift is comparable to the epistemological tensions identified by postcolonial theory in situations where hegemonic discourses encounter forms of knowledge that cannot be reduced to their universalist logic. In this sense, quantum physics emerges as a form of internal epistemological alterity within Western science: while remaining part of its canon, it simultaneously rearticulates its ontological assumptions and limits its claim to constitute the sole normative regime of rationality. Extending quantum logic into social theory enables a shift from mechanistic social ontology toward a quantum social ontology, in which relationality, co-constitution, and process take precedence over fixed entities and linear causality. This transformation unfolds as a form of passive revolution, in the Gramscian sense: a profound ontological reorientation achieved not through the destruction of disciplinary institutions, but through their gradual conceptual reconfiguration. The epistemological outcome of this shift is the pluralization of knowledge and the emergence of a pluriversal onto-epistemological horizon, where scientific rationality becomes compatible with multiple cosmologies and situated ways of knowing. In this sense, the quantum turn opens a pathway toward the decolonization of knowledge and the rethinking of global order beyond universalist epistemic hierarchies.
The growth of modern science resulted in a radically new cognitive approach to many problems of classical philosophy. In the context of contemporary theoretical physics, if only one avoids easy apologetic, it is no longer possible to defend this version of epistemological empiricism that was defended half a century ago. Whereas in the 1930’s the traditional distinction between theoretical and observational terms was called into question, due to its arbitrary nature, in the 1980’s the basic philosophical opposition between material and immaterial (resp. between physical and mathematical) objects seems arbitrary since the very notion of matter appears nothing but a terminological relic of the bygone epoch.
Contingency is everywhere, but what is it? This book defends a radical new theory of contingency as a physical phenomenon. Drawing on the many-worlds approach to quantum theory and on cutting-edge metaphysics and philosophy of science, it argues that quantum theories are best understood as telling us about the space of genuine possibilities rather than as telling us solely about actuality. When quantum physics is taken seriously in the way first proposed by Hugh Everett III, it provides the resources for a new systematic metaphysical framework encompassing possibility, necessity, actuality, chance, counterfactuals and a host of related modal notions. The framework is a modal realist one, in the tradition of David Lewis: all genuine possibilities are on a par, and the actual world is simply the one that we ourselves inhabit. It departs from Lewisian modal realism in that quantum possible worlds are not philosophical posits but scientific discoveries. Contingency and other modal notions have often been seen as beyond the limits of science. Rationalist metaphysicians argue that the metaphysics of modality is strictly prior to any scientific investigation: metaphysics establishes which worlds are possible, and physics merely checks which of these worlds is actual. Naturalistic metaphysicians respond that science may discover new possibilities and new impossibilities. This book’s quantum theory of contingency takes naturalistic metaphysics one step further, allowing that science may discover what it is to be possible. As electromagnetism revealed the nature of light, as acoustics revealed the nature of sound, as statistical mechanics revealed the nature of heat, so quantum physics reveals the nature of contingency.
Modal Actualism offers a realist, non-Everettian interpretation of quantum mechanics that preserves unitary dynamics while explaining definite outcomes without invoking collapse or branching. The central distinction is between modal structure—the full set of decoherent histories physically supported by the universal wavefunction—and actuality, the single decoherent history that is realised. Decoherence partitions modal structure into quasiclassical trajectories, but only one such trajectory constitutes the actual worldline. Probability is interpreted as modal measure: a structural feature of the wavefunction that quantifies the weight of possible histories without implying their actuality. This framework dissolves foundational paradoxes by blocking the inference from modal multiplicity to ontological multiplicity, thereby avoiding Everettian inflation while retaining the explanatory power of decoherence. Modal Actualism reconciles quantum correlations with relativistic locality and reframes cosmological fine-tuning as a feature of modal structure rather than evidence for multiverse ensembles
As we humans have expanded our horizons to see things vastly smaller, faster, larger, and farther than ever before, we have been forced to confront preconceptions born of the human experience and create wholly new ways of looking at the world around us. The theories of relativity and quantum physics were developed out of this need and have provided us with phenomenal, mind-twisting insights into the strange and exciting reality show of our universe.Relativity and Quantum Physics For Beginners is an entertaining and accessible introduction to the bizarre concepts that fueled the scientific revolution of the 20th century and led to amazing advances in our understanding of the universe.