I investigate the role of stability in cosmology through two episodes from the recent history of cosmology: Einstein’s static universe and Eddington’s demonstration of its instability, and the flatness problem of the hot big bang model and its claimed solution by inflationary theory. These episodes illustrate differing reactions to instability in cosmological models, both positive ones and negative ones. To provide some context to these reactions, I also situate them in relation to perspectives on stability from dynamical systems theory and (...) its epistemology. This reveals, for example, an insistence on stability as an extreme position in relation to the spectrum of physical systems which exhibit degrees of stability and fragility, one which has a pragmatic rationale, but not any deeper one. (shrink)

During the last three decades, there has been a growing realization among physicists and cosmologists that the relation between particle physics and cosmology may constitute yet another successful example of the unity of science. However, there are important conceptual problems in the unification of the two disciplines, e.g. in connection with the cosmological constant and the conjecture of inflation. The present article will outline some of these problems, and argue that the victory for the unity of science in the context (...) of cosmology and particle physics is still far from obvious. (shrink)

During the last three decades, there has been a growing realization among physicists and cosmologists that the relation between particle physics and cosmology may constitute yet another successful example of the unity of science. However, there are important conceptual problems in the unification of the two disciplines, e.g. in connection with the cosmological constant and the conjecture of inflation. The present article will outline some of these problems, and argue that the victory for the unity of science in the context (...) of cosmology and particle physics is still far from obvious. (shrink)

We develop and apply a multi-dimensional account of explanatory depth towards a comparative analysis of inflationary and bouncing paradigms in primordial cosmology. Our analysis builds on earlier work due to Azhar and Loeb (2021) that establishes initial conditions fine-tuning as a dimension of explanatory depth relevant to debates in contemporary cosmology. We propose dynamical fine-tuning and autonomy as two further dimensions of depth in the context of problems with instability and trans-Planckian modes that afflict bouncing and inflationary approaches respectively. In (...) the context of the latter issue, we argue that the recently formulated trans-Planckian censorship conjecture leads to a trade-off for inflationary models between dynamical fine-tuning and autonomy. We conclude with the suggestion that explanatory preference with regard to the different dimensions of depth is best understood in terms of differing attitudes towards heuristics for future model building. (shrink)

In this paper we show that any reasoning process in which conclusions can be both fallible and corrigible can be formalized in terms of two approaches: (i) syntactically, with the use of defeasible reasoning, according to which reasoning consists in the construction and assessment of arguments for and against a given claim, and (ii) semantically, with the use of partial structures, which allow for the representation of less than conclusive information. We are particularly interested in the formalization of scientific reasoning, (...) along the lines traced by Lakatos’ methodology of scientific research programs. We show how current debates in cosmology could be put into this framework, shedding light on a very controversial topic. (shrink)

The cosmological constant problem arises at the intersection between general relativity and quantum field theory, and is regarded as a fundamental problem in modern physics. In this paper we describe the historical and conceptual origin of the cosmological constant problem which is intimately connected to the vacuum concept in quantum field theory. We critically discuss how the problem rests on the notion of physically real vacuum energy, and which relations between general relativity and quantum field theory are assumed in order (...) to make the problem well-defined. (shrink)

The cosmological constant problem arises at the intersection between general relativity and quantum field theory, and is regarded as a fundamental problem in modern physics. In this paper we describe the historical and conceptual origin of the cosmological constant problem which is intimately connected to the vacuum concept in quantum field theory. We critically discuss how the problem rests on the notion of physically real vacuum energy, and which relations between general relativity and quantum field theory are assumed in order (...) to make the problem well-defined. (shrink)

The cosmic singularity provides negligible evidence for creation in the finite past, and hence theism. A physical theory might have no metric or multiple metrics, so a ‘beginning’ must involve a first moment, not just finite age. Whether one dismisses singularities or takes them seriously, physics licenses no first moment. The analogy between the Big Bang and stellar gravitational collapse indicates that a Creator is required in the first case only if a Destroyer is needed in the second. The need (...) for and progress in quantum gravity and the underdetermination of theories by data make it difficult to take singularities seriously. The singularity exemplifies the sort of gap that is likely to be closed by scientific progress, obviating special divine action. The apparent irrelevance of cardinality to practices of counting infinite sets in classical field theory and Fourier analysis is noted. Introduction The Doctrine of Creation and Its Warrant Cardinality and Sizes of Infinity Modern Cosmology and Creation Tolerance or Intolerance toward Singularities? Leibniz against Incompetent Watchmaker? Induction from Earlier Theories' Breakdown? Stellar Collapse Implies Theistic Destroyer Stacking the Deck for GTR Quantum Gravity Tends to Resolve Singularities Vicious God-of-the-Gaps Character Fluctuating or Inaccessible Warrant Big Bang Cosmology Not Especially Congenial to Faith CiteULike Connotea Del.icio.us What's this? (shrink)

The claim of inflationary cosmology to explain certain observable facts, which the Friedmann-Roberston-Walker models of `Big-Bang' cosmology were forced to assume, has already been the subject of significant philosophical analysis. However, the principal empirical claim of inflationary cosmology, that it can predict the scale-invariant power spectrum of density perturbations, as detected in measurements of the cosmic microwave background radiation, has hitherto been taken at face value by philosophers. The purpose of this paper is to expound the theory of density perturbations (...) used by inflationary cosmology, to assess whether inflation really does predict a scale-invariant spectrum, and to identify the assumptions necessary for such a derivation. The first section of the paper explains what a scale invariant power-spectrum is, and the requirements placed on a cosmological theory of such density perturbations. The second section explains and analyses the concept of the Hubble horizon, and its behaviour within an inflationary space-time. The third section expounds the inflationary derivation of scale-invariance, and scrutinises the assumptions within that derivation. The fourth section analyses the explanatory role of `horizon-crossing' within the inflationary scenario. (shrink)

I present a recent historical case from cosmology—the story of inflationary cosmology—and on its basis argue that solving explanatory problems is a reliable method for making progress in science. In particular, I claim that the success of inflationary theory at solving its predecessor’s explanatory problems justified the theory epistemically, even in advance of the development of novel predictions from the theory and the later confirmation of those predictions.

Cosmological inflation is widely considered an integral and empirically successful component of contemporary cosmology. It was originally motivated by its solution of certain so-called fine-tuning problems of the hot big bang model, particularly what are known as the horizon problem and the flatness problem. Although the physics behind these problems is clear enough, the nature of the problems depends on the sense in which the hot big bang model is fine-tuned and how the alleged fine-tuning is problematic. Without clear explications (...) of these, it remains unclear precisely what problems inflationary theory is meant to be solving and whether it does in fact solve them. I analyze the structure of these problems and consider various interpretations that may substantiate the alleged fine-tuning. On the basis of this analysis I argue that at present there is no unproblematic interpretation available for which it can be said that inflation solves the big bang model’s alleged fine-tuning problems. (shrink)

The discovery that the universe is fine-tuned for life ? a discovery to which the phrase ?the anthropic principle? is often applied ? has prompted much extra-cosmic speculation by philosophers, theologians, and theoretical physicists. Such speculation is referred to as extra-cosmic because an inference is made to the existence either of one unobservable entity that is distinct from the cosmos and any of its parts (God) or of many such entities (multiple universes). In this article a case is mounted for (...) the sceptical position that cosmic fine-tuning does not support an inference to anything extra-cosmic. To that end three definitions of ?fine-tuned for life? are proposed: the ?slight difference? definition, the (unconditional) probability definition, and John Leslie?s conditional probability definition. These three definitions are the only ones suggested by the relevant literature on fine-tuning and the anthropic principle. Since on none of them do claims of fine-tuning warrant an inference to something extracosmic, it is concluded that there is no definition of ?fine-tuned for life? serving this function. (shrink)

The Fine-Tuning Argument (FTA) is a variant of the Design Argument for the existence of God. In this paper the evidence of fine-tuning is explained and the Fine-Tuning Design Argument for God is presented. Then two objections are covered. The first objection is that fine-tuning can be explained in terms of the existence of multiple universes (the 'multiverse') plus the operation of the anthropic principle. The second objection is the 'normalizability problem'– the objection that the Fine-Tuning Argument fails because fine-tuning (...) is not actually improbable. (shrink)

There is an ongoing debate over cosmological fine-tuning between those holding that design is the best explanation and those who favor a multiverse. A small group of critics has recently challenged both sides, charging that their probabilistic intuitions are unfounded. If the critics are correct, then a growing literature in both philosophy and physics lacks a mathematical foundation. In this paper, I show that just such a foundation exists. Cosmologists are now providing the kinds of measure-theoretic arguments needed to make (...) the case for fine-tuning. Introduction Probability and infinite sets 2.1 No probability function 2.2 Arbitrary and wrong probability functions The measure of the universe The coarse-tuning objection Arbitrariness and error Conclusion. (shrink)

The idea that there might be multiple universes with different parameters of nature is often considered an attractive response to the finding that various parameters appear to be delicately fine-tuned for life. The present paper investigates whether the appeal to fine-tuning can legitimately be combined with an appeal to independent empirical evidence for other universes or whether, as suggested by Cory Juhl, combining such appeals inevitably results in illegitimate double counting of the finding that the parameters are right for life. (...) In doing so, the paper takes into account the fact that the parameters' life-friendliness is old evidence for us, which makes Bayesianism's problem of old evidence relevant to Bayesian analysis of its evidential impact. Ultimately, the verdict reached is that the warning of double counting is helpful, but that double counting can in principle be avoided. The paper highlights remaining independent challenges against the fine-tuning argument for the multiverse. (shrink)

We provide a philosophical reconstruction and analysis of the debate on the scientific status of cosmic inflation that has played out in recent years. In a series of critical papers, Ijjas et al. have questioned the scientificality of the current views on cosmic inflation. Proponents of cosmic inflation have in turn defended the scientific credentials of their approach. We argue that, while this defense, narrowly construed, is successful against Ijjas et al., the latter's reasoning does point to a significant epistemic (...) issue that arises with respect to inflation. A broadening of the concept of theory assessment is needed to address that issue in an adequate way. (shrink)

For the generalizations of thermodynamics to obtain, it appears that a very ‘special’ initial condition of the universe is required. Is this initial condition itself in need of explanation? I argue that it is not. In so doing, I offer a framework in which to think about ‘special’ initial conditions in all areas of science, though I concentrate on the case of thermodynamics. I urge the view that it is not always a serious mark against a theory that it must (...) posit an ‘improbable’ initial condition. (shrink)

I discuss how modern cosmology illustrates underdetermination of theoretical hypotheses by data, in ways that are different from most philosophical discussions. I confine the discussion to the history of the observable universe from about one second after the Big Bang, as described by the mainstream cosmological model: in effect, what cosmologists in the early 1970s dubbed the ‘standard model’, as elaborated since then. Or rather, the discussion is confined to a (very!) few aspects of that history. I emphasize that despite (...) the underdetermination, a scientific realist can, and should, endorse this description. (shrink)

I discuss how modern cosmology illustrates under-determination of theoretical hypotheses by data, in ways that are different from most philosophical discussions. I emphasise cosmology's concern with what data could in principle be collected by a single observer ; and I give a broadly sceptical discussion of cosmology's appeal to the cosmological principle as a way of breaking the under-determination.I confine most of the discussion to the history of the observable universe from about one second after the Big Bang, as described (...) by the mainstream cosmological model: in effect, what cosmologists in the early 1970s dubbed the ‘standard model’, as elaborated since then. But in the closing Section 4, I broach some questions about times earlier than one second. (shrink)

The paper presents a historical-epistemological analysis of the notion of “spontaneous symmetry breaking”, which I believe today provides a template for conceiving the relationship between symmetry and asymmetry in physics as well as in other areas of the natural sciences. The central thesis of the paper is that spontaneous symmetry breaking represents an instance of “narrative knowing” in the sense developed by recent research in history and philosophy of science (Morgan and Wise (eds) SI narrative in science, Studies in history (...) and philosophy of science, 2017a). Spontaneous symmetry breaking is best understood as a hybrid narrative comprising formulas, verbal statements, images, and at times also other media. This flexible notion can be deployed in different variations, allowing to explain a broad range of non-symmetric phenomena or models as resulting from (not necessarily observable) processes of loss of symmetry. I will support this thesis by first analysing in detail the way in which spontaneous symmetry breaking, and in particular electroweak symmetry breakdown, are presented in today’s physics textbooks and reference works, and then by reconstructing the emergence of the hybrid construct from the late 1950s until the 1970s, when spontaneous symmetry breaking definitively established itself as a key physical notion. (shrink)

Many moral debunking arguments are driven by the idea that the correlation between our moral beliefs and the moral truths is a big coincidence, given a robustly realist conception of morality.One influential response is that the correlation is not a coincidence because there is a common explainer of our moral beliefs and the moral truths. For example, the reason that I believe that I should feed my child is because feeding my child helps them to survive, and natural selection instills (...) in me beliefs and dispositions that help my children survive since that is conductive to my genes continuing through the generations. Similarly, the reason that it's morally good to feed my child is because it helps them to survive, and survival is morally valuable.But if we look at some cases from scientific practice, and from everyday life, we can see, I argue, why this response fails. A correlation can be coincidental even if there is a common explainer. I give an account of the nature of coincidence that draws upon recent literature on scientific explanation and argue that the correlation between moral belief and moral truth is a coincidence, even given such common explainers. And I use this to defend a certain form of debunking argument. (shrink)

If cosmology is to obtain knowledge about the whole universe, it faces an underdetermination problem: Alternative space-time models are compatible with our evidence. The problem can be avoided though, if there are good reasons to adopt the Cosmological Principle (CP), because, assuming the principle, one can confine oneself to the small class of homogeneous and isotropic space-time models. The aim of this paper is to ask whether there are good reasons to adopt the Cosmological Principle in order to avoid underdetermination (...) in cosmology. Various strategies to justify the CP are examined. For instance, arguments to the effect that the truth of the CP follows generically from a large set of initial conditions; an inference to the best explanation; and an inductive strategy are assessed. I conclude that a convincing justification of the CP has not yet been established, but this claim is contingent on a number of results that may have to be revised in the future. (shrink)

This article attacks “open systems” arguments that because constant conjunctions are not generally observed in the real world of open systems we should be highly skeptical that universal laws exist. This work differs from other critiques of open system arguments against laws of nature by not focusing on laws themselves, but rather on the inference from open systems. We argue that open system arguments fail for two related reasons; 1) because they cannot account for the “systems” central to their argument (...) (nor the implied systems labeled “exogenous factors” in relation to the system of interest) and 2) they are nomocentric, fixated on laws while ignoring initial and antecedent conditions that are able to account for systems and exogenous factors within a fundamentalist framework. (shrink)

The past hypothesis is that the entropy of the universe was very low in the distant past. It is put forward to explain the entropic arrow of time but it has been suggested. The emperor’s new mind. London:Vintage Books; Penrose, R.. Annals of the New York Academy of Sciences, 571, 249–264; Price, H.. In S. F. Savitt, Times’s arrows today. Cambridge: Cambridge University Press; Price, H.. Time’s arrow and Archimedes’ point. Oxford: Oxford University Press; Price, H.. In C. Hitchcock, Contemporary (...) debates in philosophy of science. Oxford: Blackwell]) that it is itself in need of explanation. It has also been suggested that cosmic inflation could provide the explanation, but Price raises a serious objection to this suggestion, which has otherwise received very little attention in the philosophical literature. Price points out that the standard inflationary explanation involves a double standard: although the evolution of the universe described by the inflationary model seems natural from the standard temporal perspective it looks highly unnatural from the reversed temporal perspective. The main purpose of this paper is to propose a novel form of the inflationary explanation that avoids this objection. It is argued that the inflationary model would not involve a double standard if we construct the model with a global “boundary” condition instead of a conventional boundary condition: if we assume that the universe is as generic as possible overall, rather than as generic as possible at some given point as is assumed in the standard inflationary model. This novel form of the inflationary explanation is then compared with Price’s 1996 preferred explanation, a version of the so-called “Weyl hypothesis”. (shrink)

A central component to scientific practice is the construction and use of scientific models. Scientists believe that the success of a model justifies making claims that go beyond the model itself. However, philosophical analysis of models suggests that drawing inferences about the world from successful models is more complex. In this dissertation I develop a framework that can help disentangle the related strands of evaluation of model success, model extendibility, and the ability to draw ampliative inferences about the world from (...) models. I present and critically assess two leading accounts of model assessment, arguing that neither is sufficient to provide a complete understanding of model evaluation. I introduce a more powerful framework incorporating elements of the two views, which can help answer these three questions: What is the target of evaluation in model assessment? How does that evaluation proceed? What licenses us in making inferences about the real world, based on the evaluation of our models as successful? The framework identifies two distinct targets of model evaluation: representational similarity between the model and target system, and the adequacy of the model as a tool to answer questions. Both assessments must be relativized to a purpose, of which there are three general kinds: descriptive, predictive, and explanatory. These purposes differ in the way they inform the similarity relation, which is relevant for the similarity assessment, and the output they produce, which is relevant for the adequacy assessment. Any model can be assessed relative to any purpose, however a model encodes certain decisions made during the model’s construction, which impact its ability to be applied to a new purpose or new domain. My framework shows that extending a model, and drawing inferences from it, depends on its representational similarity. I apply this framework to several examples taken from astrophysics showing in detail how it can help illuminate the structure of the models, as well as make the justification for inferences made from them clear. The final chapter is a detailed analysis of a contemporary debate surrounding the use of models in astrophysics, between proponents of MOND and the standard ΛCDM model. (shrink)

This dissertation shows how initial conditions play a special role in the explanation of contingent and irregular outcomes, including, in the form of geographic context, the special case of uneven development in the social sciences. The dissertation develops a general theory of this role, recognizes its empirical limitations in the social sciences, and considers how it might be applied to the question of uneven development. The primary purpose of the dissertation is to identify and correct theoretical problems in the study (...) of uneven development; it is not intended to be an empirical study. Chapter 1 introduces the basic problem, and discusses why it has become especially salient in debates concerning uneven development. Chapter 2 develops an argument for the importance of initial conditions in the philosophy of science, developed specifically in the context of the Bhaskar/Cartwright ‘open systems’ (and by extension, ‘exogenous factor’) emphasis on the ubiquity of contingency in the universe and rejection of explanation based on laws of nature (regularity accounts) of causation. Chapter 3 makes three claims concerning the concept of contingency, especially as related to the study of society: 1) that there are eight distinct uses of the word contingency, and its many meanings are detrimental to clarity of discussion and thought in history and the social sciences; 2) that it is possible to impose some order on these different uses through developing a classification of contingency into three types based on assumptions concerning possible worlds and determinism; 3) that one of the classes is a special use of the word without relevance to the social sciences, while the two remaining classes are nothing more than a variety of the ‘no hidden factors’ argument in the debate on indeterminism and determinism (and thus related to the concept of spacetime trajectories caused by initial conditions and the interference of these in the form of ‘exogenous factors’ with ‘open systems’). Chapter 4 The concept of explanation based on initial conditions together with laws of nature is widely associated with determinism. In the social sciences determinism has frequently been rejected due to the moral dilemmas it is perceived as presenting. Chapter 4 considers problems with this view. Chapter 5 considers attitudes among geographers, economists, and historians towards using geographic factors as initial conditions in explanation and how they might acceptably be used, in particular their role in ‘anchoring’ aspatial theories of social processes to real-world distributions. Chapter 6 considers the relationship of the statistical methods common in development studies with the trend towards integrating geographical factors into econometric development studies. It introduces the statistical argument on ‘apparent populations’ that arrives at conclusions concerning determinism consistent with Chapters 2 and 3 of the dissertation. The need for the visual interpretation of data with descriptive statistics and maps and their utility in the study of uneven development is discussed with a number of examples. Chapter 7 applies these concepts to the ‘institutions versus geography’ debate in development studies, using Acemoglu, Johnson and Robinson’s 2002 ‘reversal of fortune’ argument as a primary example. Chapter 8 considers possible directions for future work, both theoretical and empirical. Chapter 9 concludes with a discussion of additional possible objections to the use of initial conditions as exogenous factors in explanation. (shrink)

Our examination of universal origins and fine-tuning will begin with a discussion of infl ationary scenarios grafted onto Big Bang cosmology and the proof that all infl ationary spacetimes are past-incomplete. After diverting into a lengthy critical examination of the “different physics” offered by quantum cosmologists at the past-boundary of the universe, we will proceed to dissect the inadequacies of infl ationary explanations and string-theoretic constructs in the context of three cosmological models that have received much attention: the Steinhardt-Turok cyclic (...) ekpyrotic model (which does not invoke inflation), the Gasperini-Veneziano pre-Big Bang infl ationary model, and the inflationary string landscape model advanced by Susskind, Polchinski, Bousso, and Linde. We will argue that none of these highly speculative string cosmologies removes the necessity of a beginning to the process of universe generation, and we will emphasize the implications of this fact. Then, since the inflationary “mechanism” only really addresses the fi ne-tuning of the initial conditions of the universe and not the conditions embodied in its finely tuned laws and constants, we will analyze the adequacy of the string multiverse in its three versions (cyclic ekpyrotic, pre-Big Bang, and landscape) for explaining the nomological structure and values of these precisely tuned life-compatible universal parameters. When all is said and done, it will be clear that transcendent intelligent agency is not just the only causally suffi cient and therefore metaphysically sound explanation for universal origins and fine-tuning, but it is also much more parsimonious, elegant, and resonant with meaning than all of the ad hoc machinations of multiverse cosmology. (shrink)

Eliminative reasoning is a method that has been employed in many significant episodes in the history of science. It has also been advocated by some philosophers as an important means for justifying well-established scientific theories. Arguments for how eliminative reasoning is able to do so, however, have generally relied on a too narrow conception of evidence, and have therefore tended to lapse into merely heuristic or pragmatic justifications for their conclusions. This paper shows how a broader conception of evidence not (...) only can supply the needed justification but also illuminates the methodological significance of eliminative reasoning in a variety of contexts. (shrink)

We discuss scientific realism from the perspective of modern cosmology, especially primordial cosmology: i.e. the cosmological investigation of the very early universe. We first state our allegiance to scientific realism, and discuss what insights about it cosmology might yield, as against "just" supplying scientific claims that philosophers can then evaluate. In particular, we discuss: the idea of laws of cosmology, and limitations on ascertaining the global structure of spacetime. Then we review some of what is now known about the early (...) universe : meaning, roughly, from a thousandth of a second after the Big Bang onwards. The rest of the paper takes up two issues about primordial cosmology, i.e. the very early universe, where "very early" means, roughly, much earlier than one second after the Big Bang: say, less than 10^{-11} seconds. Both issues illustrate that familiar philosophical threat to scientific realism, the under-determination of theory by data---on a cosmic scale. The first issue concerns the difficulty of observationally probing the very early universe. More specifically, the difficulty is to ascertain details of the putative inflationary epoch. The second issue concerns difficulties about confirming a cosmological theory that postulates a multiverse, i.e. a set of domains each of whose inhabitants cannot directly observe, or otherwise causally interact with, other domains. This again concerns inflation, since many inflationary models postulate a multiverse. For all these issues, it will be clear that much remains unsettled, as regards both physics and philosophy. But we will maintain that these remaining controversies do not threaten scientific realism. (shrink)

This paper discusses the late Michael Dummett’s characterization of the estrangement between physics and philosophy. It argues against those physicists who hold that modern physics, rather than philosophy, can answer traditional metaphysical questions such as why there is something rather than nothing. The claim is that physics cannot solve metaphysical problems since metaphysical issues are in principle empirically underdetermined. The paper closes with a critical discussion of the assumption of some cosmologists that the Universe was created out of nothing: In (...) contrast to this misleading assumption, it is proposed that the Universe has a necessary existence and that the present epoch after the Big Bang is a contingent realization of the Universe. (shrink)