Anthropic reasoning has lately been strongly associated with the string theory landscape and some theories of particle cosmology, such as cosmological inflation. The association is not, contrary to multiple statements by physicists and philosophers alike, necessary. On the contrary, there are clear reasons and instances in which the anthropic reasoning is useful in a diverse range of fields such as planetary sciences, geophysics, future studies, risk analysis, origin of life studies, evolutionary theory, astrobiology and SETI studies, ecology, or even strategic (...) studies and global policy. The association of anthropic reasoning with string theory and particle cosmology has not only become the standard wisdom, but has been often construed in a negative way, in order to demonstrate or insinuate that such reasoning is too abstract or even belongs to 'fringe science', remote from run-of-the-mill research practices in any other more 'mundane' and less theoretical scientific discipline. The purpose of this paper is to (i) analyse some of the counter-examples to the standard wisdom, (ii) suggest that the anthropic reasoning is more flexible, more general, and less fashion-driven than the detractors state. In addition, we consider some historical and/or extrascientific motivation for this persistent prejudice. (shrink)

Candidates for fundamental physical laws rarely, if ever, employ higher than second time derivatives. Easwaran sketches an enticing story that purports to explain away this puzzling fact and thereby provides indirect evidence for a particular set of metaphysical theses used in the explanation. I object to both the scope and coherence of Easwaran's account, before going on to defend an alternative, more metaphysically deflationary explanation: in interacting Lagrangian field theories, it is either impossible or very hard to incorporate higher than (...) second time derivatives without rendering the vacuum state unstable. The so-called Ostrogradski instability represents a powerful constraint on the construction of new field theories and supplies a novel, largely overlooked example of non-causal explanation in physics. (shrink)

Extracting predictions from cosmological theories that describe a multiverse, for what we are likely to observe in our domain, is crucial to establishing the validity of these theories. One way to extract such predictions is from theory-generated probability distributions that allow for selection effects---generally expressed in terms of assumptions about anthropic conditionalization and how typical we are. In this paper, I urge three lessons about typicality in multiverse settings. Because it is difficult to characterize our observational situation in the multiverse, (...) we cannot assume that we are typical : nor can we ignore the issue of typicality, for it has a measurable impact on predictions for our observations. There are spectra of assumptions about both conditionalization and typicality, which lead to coincident predictions for our observations, leading to problems of confirmation in multiverse cosmology. And moreover, when one has the freedom to consider competing theories of the multiverse, the assumption of typicality may not lead to the highest likelihoods for our observations. These three entwined aspects of typicality imply that positive assertions about our typicality, such as the 'principle of mediocrity', are more questionable than has been recently claimed. (shrink)

Does the claimed fine-tuning of the constants of nature for life give reason to think that there are many other universes in which the constants have different values? Or does the inference from fine-tuning to a multiverse commit what Hacking calls the inverse gambler’s fallacy? The present paper considers two fine-tuning problems that seem promising to consider because they are in many respects analogous to the problem of the fine-tuned constants. Reasoning that parallels the inference from fine-tuning to a multiverse (...) seems prima facie adequate in these problems. However, it turns out that in both cases there are independent empirical reasons to believe the hypotheses that are analogous to the multiverse hypothesis. In the absence of such evidence, it would be coherent to raise the inverse gambler’s fallacy charge against the inference from fine-tuning to these multiverse-type hypotheses. In response to this finding, I suggest taking the possibility seriously that established standards of rationality may not allow us to decide whether the inference from fine-tuning to a multiverse is fallacious or not. The paper concludes by sceptically assessing the prospects for obtaining independent empirical evidence for concrete multiverse theories. (shrink)

A short review of some recent developments in the philosophy of physics is presented. I focus on themes which illustrate relations and points of common interest between philosophy of physics and three of its `neighboring' elds: Physics, metaphysics and general philosophy of science. The main examples discussed in these three `border areas' are decoherence and the interpretation of quantum mechanics; time in physics and metaphysics; and methodological issues surrounding the multiverse idea in modern cosmology.

I discuss the formal implementation, interpretation, and justification of likelihood attributions in cosmology. I show that likelihood arguments in cosmology suffer from significant conceptual and formal problems that undermine their applicability in this context.

Guthrie contends that religion can best be understood as systematic anthropomorphism - the attribution of human characteristics to nonhuman things and events. Religion, he says, consists of seeing the world as human like. He offers a fascinating array of examples to show how this strategy pervades secular life and how it characterizes religious experience.

This chapter addresses philosophical questions raised in contemporary work on cosmology. It provides an overview of the Standard Model for cosmology and argues that its deficiency in addressing theories regarding the very early universe can be resolved by introducing a dynamical phase of evolution that eliminates the need for a special initial state. The chapter also discusses recent hypotheses about dark matter and energy, issues that it relates to philosophical debates about underdetermination.

Anthropic reasoning has lately been strongly associated with the string theory landscape and some theories of particle cosmology, such as cosmological inflation. The association is not, contrary to multiple statements by physicists and philosophers alike, necessary. On the contrary, there are clear reasons and instances in which the anthropic reasoning is useful in a diverse range of fields such as planetary sciences, geophysics, future studies, risk analysis, origin of life studies, evolutionary theory, astrobiology and SETI studies, ecology, or even strategic (...) studies and global policy. The association of anthropic reasoning with string theory and particle cosmology has not only become the standard wisdom, but has been often construed in a negative way, in order to demonstrate or insinuate that such reasoning is too abstract or even belongs to 'fringe science', remote from run-of-the-mill research practices in any other more 'mundane' and less theoretical scientific discipline. The purpose of this paper is to (i) analyse some of the counter-examples to the standard wisdom, (ii) suggest that the anthropic reasoning is more flexible, more general, and less fashion-driven than the detractors state. In addition, we consider some historical and/or extrascientific motivation for this persistent prejudice. (shrink)

In the last three decades several cosmological principles and styles of reasoning termed 'anthropic' have been introduced into physics research and popular accounts of the universe and human beings' place in it. I discuss the circumstances of 'fine tuning' that have motivated this development, and what is common among the principles. I examine the two primary principles, and find a sharp difference between these 'Weak' and 'Strong' varieties: contrary to the view of the progenitors that all anthropic principles represent a (...) departure from Copernicanism in cosmology, the Weak Anthropic Principle is an instance of Copernicanism. It has close affinities with the step of Copernicus that Immanuel Kant took himself to be imitating in the 'critical' turn that gave rise to the Critique of Pure Reason. I conclude that the fact that a way of going about natural science mentions human beings is not sufficient reason to think that it is a subjective approach; in fact, it may need to mention human beings in order to be objective. (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)

This paper is a sequel to my 'Theological Misinterpretations of Current Physical Cosmology' (Foundations of Physics [1996], 26 (4); revised in Philo [1998], 1 (1)). There I argued that the Big Bang models of (classical) general relativity theory, as well as the original 1948 versions of the steady state cosmology, are each logically incompatible with the time-honored theological doctrine that perpetual divine creation ('creatio continuans') is required in each of these two theorized worlds. Furthermore, I challenged the perennial theological doctrine (...) that there must be a divine creative cause (as distinct from a transformative one) for the very existence of the world, a ratio essendi. This doctrine is the theistic reply to the question: 'Why is there something, rather than just nothing?' I begin my present paper by arguing against the response by the contemporary Oxford theist Richard Swinburne and by Leibniz to what is, in effect, my counter-question: 'But why should there be just nothing, rather than something?' Their response takes the form of claiming that the a priori probability of there being just nothing, vis-à-vis the existence of alternative states, is maximal, because the non-existence of the world is conceptually the simplest. On the basis of an analysis of the role of simplicity in scientific explanations, I show that this response is multiply flawed, and thus provides no basis for their three contentions that (i) if there is a world at all, then its 'normal', natural, spontaneous state is one of utter nothingness or total non-existence, so that (ii) the very existence of matter, energy and living beings constitutes a deviation from the allegedly 'normal', spontaneous state of 'nothingness', and (iii) that deviation must thus have a suitably potent (external) divine cause. Related defects turn out to vitiate the medieval Kalam Argument for the existence of God, as espoused by William Craig. Next I argue against the contention by such theists as Richard Swinburne and Philip L. Quinn that (i) the specific content of the scientifically most fundamental laws of nature, including the constants they contain, requires supra-scientific explanation, and (ii) a satisfactory explanation is provided by the hypothesis that the God of theism willed them to be exactly what they are. Furthermore, I contend that the theistic teleological gloss on the 'Anthropic Principle' is incoherent and explanatorily unavailing. Finally, I offer an array of considerations against Swinburne's attempt to show, via Bayes's theorem, that the existence of God is more probable than not. (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)

Recently, different versions of a cosmological “anthropic principle” have been used to try to explain various features of the universe. This essay, which focuses on some early uses of AP, argues that even modest appeals to it cannot be regarded as genuinely explanatory.

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)

ports the thesis that there exist very many universes. The view has found favor with a number of philosophers such as Derek Parfit ~1998!, J. J. C. Smart ~1989! and Peter van Inwagen ~1993!.1 My purpose is to argue that this is a mistake. First let me set out the issue in more detail.

It is commonly argued that an undesirable feature of a theoretical or phenomenological model is that salient observables are sensitive to values of parameters in the model. But in what sense is it undesirable to have such ‘fine-tuning’ of observables? In this paper, we argue that the fine-tuning can be interpreted as a shortcoming of the explanatory capacity of the model: in particular it signals a lack of a particular type of explanatory depth. The aspect of depth that we probe (...) relates most closely to a lack of sensitivity to changes in parameters associated with such models. In support of this argument, we develop a schema—for models that arise broadly in physical settings—that quantitatively relates fine-tuning of observables to a lack of depth of explanations based on these models. We apply our schema in two different settings in which, within each setting, we compare the depth of two competing explanations. The first setting involves explanations for the Euclidean nature of spatial slices of the universe today: in particular, we compare an explanation provided by the big-bang model of the early 1970s with an explanation provided by a general model of cosmic inflation. The second setting has a more phenomenological character, where the goal is to infer from a limited sequence of data points, using maximum entropy techniques, the underlying probability distribution from which these data are drawn. In both of these settings we find that our analysis favors the model that intuitively provides the deeper explanation of the observable of interest. We thus provide an account that relates two ‘theoretical virtues’ of models used broadly in physical settings—namely, a lack of fine-tuning and explanatory depth—and argue that finely tuned models sacrifice explanatory depth. (shrink)

-/- Some phenomena within nature exhibit such exquisiteness of structure, function or interconnectedness that many people have found it natural—if not inescapable—to see a deliberative and directive mind behind those phenomena. The mind in question, being prior to nature itself, is typically taken to be supernatural. Philosophically inclined thinkers have both historically and at present labored to shape the relevant intuition into a more formal, logically rigorous inference. The resultant theistic arguments, in their various logical forms, share a focus on (...) plan, purpose, intention and design, and are thus classified as teleological arguments (or, frequently, as arguments from or to design). -/- Although enjoying some prominent defenders over the centuries, such arguments have also attracted serious criticisms from a number of major historical and contemporary thinkers. Both critics and advocates are found not only among philosophers, but come from scientific and other disciplines as well. In the following discussion, major variant forms of teleological arguments will be distinguished and explored, traditional philosophical and other criticisms will be discussed, and the most prominent contemporary turns (cosmic fine tuning arguments, many-worlds theories, and the present Intelligent Design debate) will be tracked. Discussion will conclude with a brief look at one historically important non-inferential approach to the issue. (shrink)

When our measurement instruments sample from only a subspace of the domain that we are seeking to understand, or when they sample with uneven sampling density from the target domain, the resulting data will be affected by a selection effect. If we ignore such selection effects, our conclusions may suffer from selection biases. A classic example of selection bias is the election poll taken by the Literary Digest in 1936. On the basis of a large survey, the Digest predicted that (...) Alf Langdon, the Republican presidential candidate, would win by a large margin. But the actual election resulted in a landslide for the incumbent, Franklin D. Roosevelt. How could such a large sample yield such a wayward prediction? The Digest, it turned out, had harvested the addresses for its survey mainly from telephone books and motor vehicle registries. This introduced a strong selection effect. The poor of the depression era, a group that disproportionally supported Roosevelt, often did not have phones or cars. Observation selection effects are an especially subtle kind of selection effect that is introduced not by limitations in our measurement apparatuses but by the fact that all evidence is preconditioned on the existence of an observer to “have” the evidence and to build the instruments in the first place. Observation selection effects have only quite recently become the subject of systematic study. As well as being of philosophical interest, they are important in many scientific areas, including cosmology, parts of evolution theory, and the foundations of thermodynamics and quantum theory. There are also interesting applications to the search for extraterrestrial life and questions such as whether we might be living in a computer simulation created by an advanced civilization.. (shrink)

Cosmology raises novel philosophical questions regarding the use of probabilities in inference. This work aims at identifying and assessing lines of arguments and problematic principles in probabilistic reasoning in cosmology. -/- The first, second, and third papers deal with the intersection of two distinct problems: accounting for selection effects, and representing ignorance or indifference in probabilistic inferences. These two problems meet in the cosmology literature when anthropic considerations are used to predict cosmological parameters by conditionalizing the distribution of, e.g., the (...) cosmological constant on the number of observers it allows for. However, uniform probability distributions usually appealed to in such arguments are an inadequate representation of indifference, and lead to unfounded predictions. It has been argued that this inability to represent ignorance is a fundamental flaw of any inductive framework using additive measures. In the first paper, I examine how imprecise probabilities fare as an inductive framework and avoid such unwarranted inferences. In the second paper, I detail how this framework allows us to successfully avoid the conclusions of Doomsday arguments in a way no Bayesian approach that represents credal states by single credence functions could. -/- There are in the cosmology literature several kinds of arguments referring to self- locating uncertainty. In the multiverse framework, different "pocket-universes" may have different fundamental physical parameters. We don’t know if we are typical observers and if we can safely assume that the physical laws we draw from our observations hold elsewhere. The third paper examines the validity of the appeal to the "Sleeping Beauty problem" and assesses the nature and role of typicality assumptions often endorsed to handle such questions. -/- A more general issue for the use of probabilities in cosmology concerns the inadequacy of Bayesian and statistical model selection criteria in the absence of well-motivated measures for different cosmological models. The criteria for model selection commonly used tend to focus on optimizing the number of free parameters, but they can select physically implausible models. The fourth paper examines the possibility for Bayesian model selection to circumvent the lack of well-motivated priors. (shrink)

Adolf Grünbaum is one of the giants of 20th century philosophy of science. This volume is the first of three collecting his most essential and highly influential work. The essays collected in this first volume focus on three related areas. They discuss scientific rationality-the problem of what it takes for a theory to be called scientific, and ask whether it is plausible to draw a clear distinction between science and non-science as was famously proposed by Karl Popper. They delve into (...) the debate between determinism and indeterminism, in both science and in the humanities. Grünbaum defends the position of the Humane Determinist, which then leads to a thorough criticism of the current theological approaches to ethics and morality-where Grünbaum defends an explicit Secular Humanism-as well as of prominent theistic interpretations of twentieth century physical cosmologies. The second volume is devoted to Grünbaum's writings on the Philosophy of Physics and Space-Time, and the third to his lectures on the Philosophy of Psychology and Psychoanalysis, including his 1985 Gifford Lectures, which are to be published for the first time. (shrink)