If the laws of nature are fine-tuned for life, can we infer other universes with different laws? How could we even test such a theory without empirical access to those distant places? Can we believe in the multiverse of the Everett interpretation of quantum theory or in the reality of other possible worlds, as advocated by philosopher David Lewis? At the intersection of physics and philosophy of science, this book outlines the philosophical challenge to theoretical physics in a measured, well-grounded (...) manner. The origin of multiverse theories are explored within the context of the fine-tuning problem and a systematic comparison between the various different multiverse models are included. Cosmologists, high energy physicists, and philosophers including graduate students and researchers will find a systematic exploration of such questions in this important book. (shrink)

The multiverse theodicy proposes to reconcile the existence of God and evil by supposing that God created all and only the creation-worthy universes and that some universes like ours are, despite their evils, creation-worthy. Drawing on work in population ethics, this paper develops a novel challenge to the multiverse theodicy. Roughly, the challenge contends that the axiological underpinnings of the multiverse theodicy harbor a ‘mere addition paradox’: the assumption that creating creation-worthy universes would always make the world better turns out (...) to have morally repugnant consequences akin to those of the assumption that adding worthwhile lives to a population would always make the overall welfare of the population better. Further, the challenge leverages this difficulty into an argument against God’s having created all and only the creation-worthy universes, and hence against the multiverse theodicy. Responses to this challenge are considered but found wanting, largely because of commitments of the multiverse theodicy that have no analogs in population ethics. (shrink)

In this article, I develop a novel version of the multiverse theory of sets called hierarchical pluralism by introducing the notion of “degrees of intentionality” of theories. The presented view is articulated for the purpose of reconciling epistemological realism and the multiverse theory of sets so as to preserve a considerable amount of epistemic objectivity when working with the multiverse theory. I give some arguments in favor of a hierarchical picture of the multiverse in which theories or models are thought (...) to be ordered with respect to their plausibility as a manifestation of endorsing the idea that some set theories are more plausible than others. The proposed multiverse account settles the pluralist’s dilemma, the dichotomy that there is a trade-off between the richness of mathematical ontology and the objectivity of mathematical truth. The view also extends and serves as an alternative position to Balaguer’s intention-based Platonism, from which he claims that a certain version of mathematical pluralism follows. (shrink)

In reply to the problem of evil, some suggest that God created an infinite number of universes—for example, that God created every universe that contains more good than evil. I offer two objections to these multiverse theodicies. First, I argue that, for any number of universes God creates, he could have created more, because he could have created duplicates of universes. Next, I argue that multiverse theodicies can’t adequately account for why God would create universes with pointless suffering, and hence (...) they don’t solve the problem of evil. (shrink)

We review different conceptions of the set-theoretic multiverse and evaluate their features and strengths. In Sect. 1, we set the stage by briefly discussing the opposition between the ‘universe view’ and the ‘multiverse view’. Furthermore, we propose to classify multiverse conceptions in terms of their adherence to some form of mathematical realism. In Sect. 2, we use this classification to review four major conceptions. Finally, in Sect. 3, we focus on the distinction between actualism and potentialism with regard to the (...) universe of sets, then we discuss the Zermelian view, featuring a ‘vertical’ multiverse, and give special attention to this multiverse conception in light of the hyperuniverse programme introduced in Arrigoni and Friedman (2013). We argue that the distinctive feature of the multiverse conception chosen for the hyperuniverse programme is its utility for finding new candidates for axioms of set theory. (shrink)

Multiverse Views in set theory advocate the claim that there are many universes of sets, no-one of which is canonical, and have risen to prominence over the last few years. One motivating factor is that such positions are often argued to account very elegantly for technical practice. While there is much discussion of the technical aspects of these views, in this paper I analyse a radical form of Multiversism on largely philosophical grounds. Of particular importance will be an account of (...) reference on the Multiversist conception, and the relativism that it implies. I argue that analysis of this central issue in the Philosophy of Mathematics indicates that Radical Multiversism must be algebraic, and cannot be viewed as an attempt to provide an account of reference without a softening of the position. (shrink)

In this article we analyze the method of forcing from a more philosophical perspective. After a brief presentation of this technique we outline some of its philosophical imports in connection with realism. We shall discuss some philosophical reactions to the invention of forcing, concentrating on Mostowski’s proposal of sharpening the notion of generic set. Then we will provide an overview of the notions of multiverse and the related philosophical debate on the foundations of set theory. In conclusion, we connect this (...) modern debate and Mostowski’s proposal, suggesting a way to analyze the notion of genericity within the framework of a multiverse structure. (shrink)

A multiverse is comprised of many universes, which quickly leads to the question: How many universes? There are either finitely many or infinitely many universes. The purpose of this paper is to discuss two conceptions of infinite number and their relationship to multiverses. The first conception is the standard Cantorian view. But recent work has suggested a second conception of infinite number, on which infinite numbers behave very much like finite numbers. I will argue that that this second conception (...) of infinite number is the correct one, and analyze what this means for multiverses. (shrink)

I provide the account of divine creation found in multiverse theorists Donald Turner, Klaas Kraay, and Tim O’Connor. I show that the accounts Kraay and Turner offer are incoherent. God does not survey all possible worlds and necessarily actualize those universes in the (on balance) good worlds or the worthy worlds. If God necessarily actualizes the multiverse, we have no idea which universes are parts of that multiverse. I show next that Tim O’Connor’s multiverse account of creation is also incoherent. (...) I argue that a preferable multiverse would include a much greater variety of universes than are included in Turner, Kraay or O’Connor. In the last section I offer some concluding remarks. (shrink)

We review different conceptions of the set-theoretic multiverse and evaluate their features and strengths. In Sect. 1, we set the stage by briefly discussing the opposition between the ‘universe view’ and the ‘multiverse view’. Furthermore, we propose to classify multiverse conceptions in terms of their adherence to some form of mathematical realism. In Sect. 2, we use this classification to review four major conceptions. Finally, in Sect. 3, we focus on the distinction between actualism and potentialism with regard to the (...) universe of sets, then we discuss the Zermelian view, featuring a ‘vertical’ multiverse, and give special attention to this multiverse conception in light of the hyperuniverse programme introduced in Arrigoni-Friedman :77–96, 2013). We argue that the distinctive feature of the multiverse conception chosen for the hyperuniverse programme is its utility for finding new candidates for axioms of set theory. (shrink)

As a candidate theory of quantum gravity, the popularity of string theory has waxed and waned over the past four decades. One current source of scepticism is that the theory can be used to derive, depending upon the input geometrical assumptions that one makes, a vast range of different quantum field theories, giving rise to the so-called landscape problem. One apparent way to address the landscape problem is to posit the existence of a multiverse; this, however, has in turn drawn (...) heightened attention to questions regarding the empirical testability and predictivity of string theory. We argue first that the landscape problem relies on dubious assumptions and does not motivate a multiverse hypothesis. Nevertheless, we then show that the multiverse hypothesis is scientifically legitimate and could be coupled to string theory for other empirical reasons. Looking at various cosmological approaches, we offer an empirical criterion to assess the scientific status of multiverse hypotheses. (shrink)

David Wallace argues that we should take quantum theory seriously as an account of what the world is like--which means accepting the idea that the universe is constantly branching into new universes. He presents an accessible but rigorous account of the 'Everett interpretation', the best way to make coherent sense of quantum physics.

The multiverse view in set theory, introduced and argued for in this article, is the view that there are many distinct concepts of set, each instantiated in a corresponding set-theoretic universe. The universe view, in contrast, asserts that there is an absolute background set concept, with a corresponding absolute set-theoretic universe in which every set-theoretic question has a definite answer. The multiverse position, I argue, explains our experience with the enormous range of set-theoretic possibilities, a phenomenon that challenges the universe (...) view. In particular, I argue that the continuum hypothesis is settled on the multiverse view by our extensive knowledge about how it behaves in the multiverse, and as a result it can no longer be settled in the manner formerly hoped for. (shrink)

We develop an untyped framework for the multiverse of set theory. $\mathsf {ZF}$ is extended with semantically motivated axioms utilizing the new symbols $\mathsf {Uni}(\mathcal {U})$ and $\mathsf {Mod}(\mathcal {U, \sigma })$, expressing that $\mathcal {U}$ is a universe and that $\sigma $ is true in the universe $\mathcal {U}$, respectively. Here $\sigma $ ranges over the augmented language, leading to liar-style phenomena that are analyzed. The framework is both compatible with a broad range of multiverse conceptions and suggests its (...) own philosophically and semantically motivated multiverse principles. In particular, the framework is closely linked with a deductive rule of Necessitation expressing that the multiverse theory can only prove statements that it also proves to hold in all universes. We argue that this may be philosophically thought of as a Copernican principle that the background theory does not hold a privileged position over the theories of its internal universes. Our main mathematical result is a lemma encapsulating a technique for locally interpreting a wide variety of extensions of our basic framework in more familiar theories. We apply this to show, for a range of such semantically motivated extensions, that their consistency strength is at most slightly above that of the base theory $\mathsf {ZF}$, and thus not seriously limiting to the diversity of the set-theoretic multiverse. We end with case studies applying the framework to two multiverse conceptions of set theory: arithmetic absoluteness and Joel D. Hamkins’ multiverse theory. (shrink)

The intended title was “Universe Oriented Ontology” or “Multiverse Oriented Ontology”, or “Universe or Multiverse Metaphysics”. I mention this as it gives an idea about the meaning and intention of the title and the work as well as the titles I considered and why I moved away from them to the present one. The sub-title provides a further hint towards the intentions of the work, namely: ” Beyond Earth- and Human-centricity’. I opted for ‘transcending’ rather than beyond, as I am (...) still in the process of describing the process of transcending and many of the ideas I am obliged to use from our conceptual system and practices are still earth- and anthropo-centered, And, they have not yet gone to a state beyond those two -isms. I say something about universe-centeredness, then about planet earth as point and frame of reference and anthropo-centricity. The socio-cultural practice of philosophy and the doing of philosophy is merely one of many human, social and cultural practices. I post different notions of philosophy by a number of writers, some of them philosophers. These notions are about their perceptions of what philosophy is. Few of them go into detail about the subject-matter of philosophy. No one really deal with the aims, purposes and objectives of the discipline and none deal with the nature of the doing of philosophy or philosophizing. Activities that I suggest resemble certain features of the processes of theorizing. I end with explorations of possible characteristics of original- and creative thinkers. I do this by mentioning a number of themes of meta-philosophy listed and described by Peter Suber. I make a number of comments in them and highlight aspects relevant to these type of thinkers. One find them of course in all disciplines and socio-cultural [racticesand disciplines be they the arts,humanities, sciences, etc. I am of course specifically concerned with original andcreative thinkers inthe Western tradition of philosophy. As I am a radical and absolute sceptic, I end with an article on this theme. It is said by everyone, for example Hume, Russell and Pascal, that such a radical position is psychologically impossible and that it cannot be lived 24/7. Pascal for example opted for believe or faith and he and a number of writers suggest that that is the only way out and the final position of radical sceptics. I disagree with him. (shrink)

Recent advances in string theory and inflationary cosmology have led to a surge of interest in the possible existence of an ensemble of cosmic regions, or “universes”, among the members of which key physical parameters, such as the masses of elementary particles and the coupling constants, might assume different values. The observed values in our cosmic region are then attributed to an observer selection effect (the so-called anthropic principle). The assemblage of universes has been dubbed “the multiverse”. In this paper (...) we review the multiverse concept and the criticisms that have been advanced against it on both scientific and philosophical grounds. (shrink)

The multiverse hypothesis is one of the leading proposed explanations of cosmic fine-tuning for life. One common objection to the multiverse hypothesis is that, even if it were true, it would not explain why this universe, our universe, is fine-tuned for life. To think it would so explain is allegedly to commit “the inverse gambler's fallacy.” This paper presents what the inverse gambler's fallacy is supposed to be, then surveys the discussion of it in the philosophical literature of the last (...) 35 years. (shrink)

The multiverse hypothesis is growing in popularity among theistic philosophers because some view it as the preferable way to solve certain difficulties presented by theistic belief. In this paper, I am concerned specifically with its application to Rowe’s problem of no best world, which suggests that God’s existence is impossible given the fact that the world God actualizes must be unsurpassable, yet for any given possible world, there is one greater. I will argue that, as a solution to the problem (...) of no best world, the multiverse hypothesis fails. To defend my thesis, I will first define the multiverse hypothesis and articulate the problem of no best world and how the multiverse hypothesis is thought to solve it. I will then show that the solution fails by articulating two problems that have been mentioned, but not developed, in the literature—what I call the problem of no highest standard and the problem of multiverse cardinality. In each case, after articulating the problem, I will offer possible responses to the problem and show why those responses are inadequate. (shrink)

Multiverses are predictions based on theories. Focusing on each theory’s assumptions is key to evaluating a proposed multiverse. Although accepted theories of particle physics and cosmology contain non-intuitive features, multiverse theories entertain a host of “strange” assumptions classified as metaphysical topics such as: infinity, duplicate yous, hypothetical fields, more than three space dimensions, Hilbert space, advanced civilizations, and reality established by mathematical relationships. It is easy to confuse multiverse proposals because many divergent models exist. This overview defines the characteristics (...) of eleven popular multiverse proposals. The characteristics compared are: initial conditions, values of constants, laws of nature, number of space dimensions, number of universes, and fine tuning explanations. Future scientific experiments may validate selected assumptions; but until they do, proposals by philosophers may be as valid as theoretical scientific theories. (shrink)

Multiverses are predictions based on theories. Focusing on each theory’s assumptions is key to evaluating a proposed multiverse. Although accepted theories of particle physics and cosmology contain non-intuitive features, multiverse theories entertain a host of “strange” assumptions classified as metaphysical topics such as: infinity, duplicate yous, hypothetical fields, more than three space dimensions, Hilbert space, advanced civilizations, and reality established by mathematical relationships. It is easy to confuse multiverse proposals because many divergent models exist. This overview defines the characteristics (...) of eleven popular multiverse proposals. The characteristics compared are: initial conditions, values of constants, laws of nature, number of space dimensions, number of universes, and fine tuning explanations. Future scientific experiments may validate selected assumptions; but until they do, proposals by philosophers may be as valid as theoretical scientific theories. (shrink)

Recent developments in cosmology and particle physics have led to speculation that our universe is merely one of a multitude of universes. While this notion, the multiverse hypothesis, is highly contested as legitimate science, it has nonetheless struck many physicists as a necessary consequence of the effort to construct a final, unified theory. In Process and Reality (1929), his magnum opus, Alfred North Whitehead advanced a cosmology as part of his general metaphysics of process. Part of this project involved a (...) theory of cosmic epochs which bears a remarkable affinity to current cosmological speculation. This paper demonstrates how the basic framework of a multiverse theory is already present in Whitehead’s cosmology and defends the necessity of speculation in the quest for an explanatory description. (shrink)

Given recent scientific findings suggesting that our world is part of a multiverse, Leland Harper argues that we ought to abandon the idea of an active God in Judeo-Christian theism. This shift results in a more coherent, cohesive and, ultimately, better account of God than is currently offered by the Judeo-Christian monotheistic tradition.

We argue that Kraay's "theistic multiverse" response to the objections to theism [Kraay 2011] is unsuccessful as it simply shifts the problems leveled against theism from the level of possible worlds to the level of possible universes. Furthermore, when we restate the objections at the level of possible universes, we can show how Kraay's conclusion about the uniqueness of the theistic multiverse is undermined.

From a physical point of view, the no-boundary Hartle-Hawking model put forward in 1983 was an attempt to demonstrate that the incorporation of quantum effects into the general theory of relativity would solve the problem of singularities that make the theory of relativity incomplete. This was achieved by imposing the so called “no-boundary conditions” whereby the Universe could emerge with non-zero probability from a non-existing state. Stephen Hawking quickly turned this result into a metaphysical claim that physical laws explained away (...) the necessity of the Divine intervention at the origin of the Universe. This paper offers an inquiry into the line of arguments presented by Hawking and Mlodinow in their book The Grand Design and supported with the claim that the yet unknown versionof the superstring theory, the M-theory, is an ultimate theory of the Universe. The upshot of the paper is that although the argument in the Grand Design relies on the newer achievements of physics embedded in the controversial multi-verse setting, it does not escape the question of the origin of the most general laws of physics that bring the Universe into existence. (shrink)

Some analytic philosophers of religion argue that theists should embrace the hypothesis of the multiverse to address the problem of evil and make the concept of a “best possible creation” plausible. I discuss what classical theists, such as Augustine, Anselm, and Aquinas, might make of the multiverse hypothesis including issues such as: the principle of plenitude, what a classical theist multiverse could look like, and how a classical theist multiverse could deal with the problem of evil and the question of (...) a best possible creation. (shrink)

Presents a comprehensive history of multiverse theory, reviewing the discoveries that shaped astrophysicists' current consensus view while showing that the multiverse is able to be explained entirely in naturalistic terms.

I present and defend an “indexical” version of the Fine-Tuning Argument. I begin by outlining the dialectic between the Fine-Tuning Argument, the Multiverse Objection, and the This-Universe Reply. Next, I sketch an indexical fine-tuning argument and defend it from two new objections. Then, I show that such an argument is immune to the Multiverse Objection. I explain how a further augmentation to the argument allows it to avoid an objection I call the “Indifference Objection.” I conclude that my indexical version (...) of the Fine-Tuning Argument is no less cogent than the standard version, and yet it is immune to the Multiverse Objection. (shrink)

Anselm’s ontological argument for the existence of God is examined. It is concluded that Anselm errs in assuming the greatest "thing" must be a sentient being. The existence of God, then, is not established by Anselm’s argument, and is concluded to be unlikely for other reasons as well, one being that a perfected sentient being would be a logical impossibility. An afterlife and personal immortality are not precluded however; these goals could be reached by future scientific means. For now cryonics (...) is advocated as a means to reach a more advanced future when death may be physically overcome. (shrink)

The objective of this paper is analyzing to which extent the multiverse hypothesis provides a real explanation of the peculiarities of the laws and constants in our universe. First we argue in favor of the thesis that all multiverses except Tegmark’s “mathematical multiverse” are too small to explain the fine tuning, so that they merely shift the problem up one level. But the “mathematical multiverse" is surely too large. To prove this assessment, we have performed a number of experiments (...) with cellular automata of complex behavior, which can be considered as universes in the mathematical multiverse. The analogy between what happens in some automata (in particular Conway’s “Game of Life") and the real world is very strong. But if the results of our experiments can be extrapolated to our universe, we should expect to inhabit—in the context of the multiverse—a world in which at least some of the laws and constants of nature should show a certain time dependence. Actually, the probability of our existence in a world such as ours would be mathematically equal to zero. In consequence, the results presented in this paper can be considered as an inkling that the hypothesis of the multiverse, whatever its type, does not offer an adequate explanation for the peculiarities of the physical laws in our world. (shrink)

Few topics in cosmology are as hotly debated as the Multiverse: for some it is untestable and hence unscientific; for others it is unavoidable and a natural extension of previous science. A third position is that it is seen to follow from other theories, but those other theories might themselves be seen as too speculative. The idea of fine-tuning has a similar status. Some of this disagreement might be due to misunderstanding, in particular the degree to which probability distributions are (...) necessary to interpret conclusions based on the Multiverse, especially with regard to the Anthropic Principle. I present undisputed facts, discuss some common misunderstandings, and investigate the role played by probability. The Multiverse is perhaps an important component necessary for interpreting cosmological and other physical parameters. (shrink)

In the Marvel Cinematic Universe (MCU), according to the Ancient One, magic is created by drawing energy from the other dimensions of the multiverse. This sounds like a concept from science fiction, but the idea that people are living in a vast multiverse is very possibly science fact. A recurring and especially important theme in Doctor Strange is the role that human beings are supposed to play in the universe. The concept of the multiverse is well established in the Marvel (...) comics and has officially been introduced into the MCU, and the way it is introduced touches on central issues in the philosophy of physics. Quantum mechanics is hands‐down one of the greatest accomplishments of science. Understanding the apparent collapse of the wave function upon observation is the core of the measurement problem. There are different ways of explaining this, which are called “interpretations” of quantum mechanics. (shrink)

In this paper, an evolutionary multiverse argument against naturalism (EMAAN) is presented: E1. In an evolutionary multiverse, phenomena have variable evolutionary ages. E2. After some time T, the development of the empirical sciences will be evolutionarily conserved. E3. The phenomena with an evolutionary age above T are methodologically supernatural. Entities are classified according to whether they are (1) physical and spatiotemporal, (2) causally efficacious, and (3) either observed by or explanatorily necessary for the empirical sciences. While the conjunction of (1) (...) and (2) is taken to be sufficient for existence in reality, the negation of (3) defines methodological supernaturalness. EMAAN uses a generalization of evolutionary theory, namely cosmological natural selection, to argue that phenomena evolve that fulfill conditions (1) and (2), but not (3). This shows that methodologically supernatural phenomena have a clear epistemology according to a theory that is grounded in the commitments of naturalism. Supernatural phenomena are not observed by the empirical sciences because the empirical sciences themselves are supernaturally guided and predestined to develop according to an evolutionarily conserved plan. In spite of this scientific plan, there is room for afterlives and supernaturality in the everyday experience. (shrink)

Suppose that reality consists of parallel universes of every variety imaginable. No path through space and time leads from one to another, and each universe is causally isolated from the rest. Some physicists believe a ‘multiverse’ hypothesis not terribly distant from this one simplifies quantum mechanics and provides an elegant explanation of why our universe has its particular laws. Suppose as science advances we come to accept the multiverse hypothesis, so construed.

Cosmological models that invoke a multiverse - a collection of unobservable regions of space where conditions are very different from the region around us - are controversial, on the grounds that unobservable phenomena shouldn't play a crucial role in legitimate scientific theories. I argue that the way we evaluate multiverse models is precisely the same as the way we evaluate any other models, on the basis of abduction, Bayesian inference, and empirical success. There is no scientifically respectable way to do (...) cosmology without taking into account different possibilities for what the universe might be like outside our horizon. Multiverse theories are utterly conventionally scientific, even if evaluating them can be difficult in practice. (shrink)

In a recent paper in this journal, Jason Megill (2011) offers an innovative meta-argument which deploys considerations about multiple universes in an effort to block all arguments from evil. In what follows, I contend that Megill has failed to establish a key premise in his meta-argument. I also offer a rival account of the effect of multiverse models on the debate about evil.

In recent decades, scientific theories have postulated the existence of many universes beyond our own. The details and implications of these theories are hotly contested. Some philosophers argue that these scientific models count against the existence of God. Others, however, argue that if God exists, a multiverse is precisely what we should expect to find. Moreover, these philosophers claim that the idea of a divinely created multiverse can help believers in God respond to certain arguments for atheism. These proposals are, (...) of course, also extremely controversial. This volume collects together twelve newly published essays – two by physicists, and ten by philosophers – that discuss various aspects of this issue. Some of the essays support the idea of a divinely created multiverse; others oppose it. Scientific, philosophical, and theological issues are considered. (shrink)

Penelope Maddy has recently addressed the set-theoretic multiverseset-theoretic multiverse, and expressed reservations on its status and merits Foundations of mathematics. Essays in honor of W. Hugh Woodin’s 60th birthday. Contemporary mathematics. American Mathematical Society, Providence, pp. 289–322, 2017). The purpose of the paper is to examine her concerns, by using the interpretative framework of set-theoretic naturalismset-theoretic naturalism. I first distinguish three main forms of ‘multiversism’multiversism, and then I proceed to analyse MaddyMaddy’s concerns. Among other things, I take into account salient (...) aspects of multiverse-related mathematics, in particular, research programmes in set theory for which the use of the multiverse seems to be crucial, and show how one may provide responses to MaddyMaddy’s concerns based on a careful analysis of ‘multiverse practice’. (shrink)

I present and defend an “indexical” version of the Fine-Tuning Argument. I begin by outlining the dialectic between the Fine-Tuning Argument, the Multiverse Objection, and the This-Universe Reply. Next, I sketch an indexical fine-tuning argument and defend it from two new objections. Then, I show that such an argument is immune to the Multiverse Objection. I explain how a further augmentation to the argument allows it to avoid an objection I call the “Indifference Objection.” I conclude that my indexical version (...) of the Fine-Tuning Argument is no less cogent than the standard version, and yet it is immune to the Multiverse Objection. (shrink)

One might suppose that Everettian quantum mechanics (EQM) is inhospitable to metaphysial indeterminacy (MI), given that, as A. Wilson (2020) puts it, "the central idea of EQM is to replace indeterminacy with multiplicity" (77). But as Wilson goes on to suggest, the popular decoherence-based understanding of EQM (henceforth: DEQM) appears to admit of indeterminacy in both world number and world nature, where the latter indeterminacy---our focus here---is plausibly metaphysical. After a brief presentation of DEQM (S1), we bolster the case for (...) there being MI in world nature in DEQM (S2). The remainder of the paper is devoted to a comparative assessment of the two main approaches to MI for purposes of accommodating this MI---namely, a metaphysical supervaluationist approach (as per Barnes and Williams 2011) and a determinable-based approach (as per Wilson 2013 and Calosi and Wilson 2018 and 2021). We briefly describe each approach (S3), then offer arguments in favour of a determinable-based approach to world nature MI in DEQM (S4). (shrink)

Penelope Maddy has recently addressed the set-theoretic multiverse, and expressed reservations on its status and merits ([Maddy, 2017]). The purpose of the paper is to examine her concerns, by using the interpretative framework of set-theoretic naturalism. I first distinguish three main forms of 'multiversism', and then I proceed to analyse Maddy's concerns. Among other things, I take into account salient aspects of multiverse-related mathematics , in particular, research programmes in set theory for which the use of the multiverse seems to (...) be crucial, and show how one may provide responses to Maddy's concerns based on a careful analysis of 'multiverse practice'. (shrink)

The multiverse is a hypothesis for which there is no evidence, and perhaps can never be any evidence. It is only since 1998 that it has leapt off the blackboards of a few physicists doing esoteric mathematics and lodged itself in the popular imagination. As is the way with popular science, it is easy to move from speculating that there might have been more than one big bang to proceeding on the basis that there has been more than one big (...) bang. (shrink)

There is a long-lasting controversy concerning our mind and consciousness. The book proposes a connection between the mind the brain and the multiverse. We introduce the main philosophical ideas concerning mind and freedom. Explain the basic principles of computer science, artificial intelligence of brain research, quantum physics and quantum artificial intelligence. We indicate how we can provide an answer to the problem of the mind and consciousness by describing the nature of the physical world. Our proposed explanation includes the Everett (...) Many-worlds theory. The book tries to avoid any non-essential metaphysical speculations. The book is an essential compilation of knowledge in philosophy, computer science, biology, and quantum physics. It is written for readers without any requirements in mathematics, physics, or computer science. (shrink)

In this paper I apply the concept of _inter-Model Inconsistency in Set Theory_ (MIST), introduced by Carolin Antos (this volume), to select positions in the current universe-multiverse debate in philosophy of set theory: I reinterpret H. Woodin’s _Ultimate L_, J. D. Hamkins’ multiverse, S.-D. Friedman’s hyperuniverse and the algebraic multiverse as normative strategies to deal with the situation of de facto inconsistency toleration in set theory as described by MIST. In particular, my aim is to situate these positions on the (...) spectrum from inconsistency avoidance to inconsistency toleration. By doing so, I connect a debate in philosophy of set theory with a debate in philosophy of science about the role of inconsistencies in the natural sciences. While there are important differences, like the lack of threatening explosive inferences, I show how specific philosophical positions in the philosophy of set theory can be interpreted as reactions to a state of inconsistency similar to analogous reactions studied in the philosophy of science literature. My hope is that this transfer operation from philosophy of science to mathematics sheds a new light on the current discussion in philosophy of set theory; and that it can help to bring philosophy of mathematics and philosophy of science closer together. (shrink)

The forcing method is a powerful tool to prove the consistency of set-theoretic assertions relative to the consistency of the axioms of set theory. Laver’s theorem and Bukovský’s theorem assert that set-generic extensions of a given ground model constitute a quite reasonable and sufficiently general class of standard models of set-theory.In Sects. 2 and 3 of this note, we give a proof of Bukovsky’s theorem in a modern setting ). In Sect. 4 we check that the multiverse of set-generic extensions (...) can be treated as a collection of countable transitive models in a conservative extension of ZFC. The last section then deals with the problem of the existence of infinitely-many independent buttons, which arose in the modal-theoretic approach to the set-generic multiverse by Hamkins and Loewe :1793–1817, 2008). (shrink)