Fine-tuning in physics and cosmology is often used as evidence that a theory is incomplete. For example, the parameters of the standard model of particle physics are “unnaturally” small, which has driven much of the search for physics beyond the standard model. Of particular interest is the fine-tuning of the universe for life, which suggests that our universe’s ability to create physical life forms is improbable and in need of explanation, perhaps by a multiverse. This claim has been challenged on (...) the grounds that the relevant probability measure cannot be justified because it cannot be normalized, and so small probabilities cannot be inferred. We show how fine-tuning can be formulated within the context of Bayesian theory testing in the physical sciences. The normalizability problem is seen to be a general problem for testing any theory with free parameters, and not a unique problem for fine-tuning. Physical theories in fact avoid such problems in one of two ways. Dimensional parameters are bounded by the Planck scale, avoiding troublesome infinities, and we are not compelled to assume that dimensionless parameters are distributed uniformly, which avoids non-normalizability. (shrink)

“Absence of evidence isn’t evidence of absence” is a slogan that is popular among scientists and nonscientists alike. This article assesses its truth by using a probabilistic tool, the Law of Likelihood. Qualitative questions (“Is E evidence about H ?”) and quantitative questions (“How much evidence does E provide about H ?”) are both considered. The article discusses the example of fossil intermediates. If finding a fossil that is phenotypically intermediate between two extant species provides evidence that those species have (...) a common ancestor, does failing to find such a fossil constitute evidence that there was no common ancestor? Or should the failure merely be chalked up to the imperfection of the fossil record? The transitivity of the evidence relation in simple causal chains provides a broader context, which leads to discussion of the fine-tuning argument, the anthropic principle, and observation selection effects. (shrink)

Bird argues that Armstrong’s necessitarian conception of physical modality and laws of nature generates a vicious regress with respect to necessitation. We show that precisely the same regress afflicts Bird’s dispositional-monist theory, and indeed, related views, such as that of Mumford & Anjum. We argue that dispositional monism is basically Armstrongian necessitarianism modified to allow for a thesis about property identity.

I argue that the rationale behind the fine-tuning argument for design is self-undermining, refuting the argument’s own premise that fine-tuning is to be expected given design. In (Weisberg 2010) I argued on informal grounds that this premise is unsupported. White (2011) countered that it can be derived from three plausible assumptions. But White’s third assumption is based on a fallacious rationale, and is even objectionable by the design theorist’s own lights. The argument that shows this, the argument from divine indifference, (...) simultaneously exposes the fine-tuning argument’s self-undermining character. The same argument also answers Bradley’s (forthcoming) reply to my earlier objection. (shrink)

I argue that the standard way of formalizing the fine-tuning argument for design is flawed, and I present an alternative formalization. On the alternative formalization, the existence of life is not treated as the evidence that confirms design; instead it is treated as part of the background knowledge, while the fact that fine tuning is required for life serves as the evidence. I argue that the alternative better captures the informal line of thought that gives the fine-tuning argument its intuitive (...) plausibility, and I show that the alternative formalization avoids all of the most prominent objections to the fine-tuning argument, including the objection from observation selection effects, the problem of old evidence, the problem of non-normalizable probability measures and a further objection due to Monton. I conclude that the alternative formalization is the one that attention should be focused on. (shrink)

The fine-tuning argument can be used to support the Many Universe hypothesis. The Inverse Gambler’s Fallacy objection seeks to undercut the support for the Many Universe hypothesis. The objection is that although the evidence that there is life somewhere confirms Many Universes, the specific evidence that there is life in this universe does not. I will argue that the Inverse Gambler’s Fallacy is not committed by the fine-tuning argument. The key issue is the procedure by which the universe with life (...) is selected for observation. Once we take account of the procedure, we find that the support for the Many Universe hypothesis remains. (shrink)

The fundamental constants that are involved in the laws of physics which describe our universe are finely-tuned for life, in the sense that if some of the constants had slightly different values life could not exist. Some people hold that this provides evidence for the existence of God. I will present a probabilistic version of this fine-tuning argument which is stronger than all other versions in the literature. Nevertheless, I will show that one can have reasonable opinions such that the (...) fine-tuning argument doesn’t lead to an increase in one’s probability for the existence of God. (shrink)

This article defends the Doomsday Argument, the Halfer Position in Sleeping Beauty, the Fine-Tuning Argument, and the applicability of Bayesian confirmation theory to the Everett interpretation of quantum mechanics. It will argue that all four problems have the same structure, and it gives a unified treatment that uses simple models of the cases and no controversial assumptions about confirmation or self-locating evidence. The article will argue that the troublesome feature of all these cases is not self-location but selection effects.

Recently Díaz, Hössjer and Marks (DHM) presented a Bayesian framework to measure cosmological tuning (either fine or coarse) that uses maximum entropy (maxent) distributions on unbounded sample spaces as priors for the parameters of the physical models (https://doi.org/10.1088/1475-7516/2021/07/020). The DHM framework stands in contrast to previous attempts to measure tuning that rely on a uniform prior assumption. However, since the parameters of the models often take values in spaces of infinite size, the uniformity assumption is unwarranted. This is known as (...) the normalization problem. In this paper we explain why and how the DHM framework not only evades the normalization problem but also circumvents other objections to the tuning measurement like the so called weak anthropic principle, the selection of a single maxent distribution and, importantly, the lack of invariance of maxent distributions with respect to data transformations. We also propose to treat fine-tuning as an emergence problem to avoid infinite loops in the prior distribution of hyperparameters (common to all Bayesian analysis), and explain that previous attempts to measure tuning using uniform priors are particular cases of the DHM framework. Finally, we prove a theorem, explaining when tuning is fine or coarse for different families of distributions. The theorem is summarized in a table for ease of reference, and the tuning of three physical parameters is analyzed using the conclusions of the theorem. (shrink)

This paper investigates ‘exterminous hypertime’, a model of time travel in which time travellers can change the past in virtue of there being two dimensions of time. This paper has three parts. Part one discusses the laws which might govern the connection between different ‘hypertimes’, showing that there are no problems with overdetermination. Part two examines a set of laws that mean changes to history take a period of hypertime to propagate through to the present. Those laws are of interest (...) because: (i) at such worlds, a particular problem for non-Ludovician time travel (‘the multiple time travellers’ problem) is avoided; and (ii) they allow us to make sense of certain fictional narratives. Part three discusses how to understand expectations and rational decision making in a world with two dimensions of time. I end with an appendix discussing how the different theories in the metaphysics of time (e.g., tensed/tenseless theories and presentism/eternalism/growing block theory) marry up with exterminous hypertime. (shrink)

استدلال بر وجود خدا از طریق توسل به تنظیم‌ظریف کیهان، تنظیم‌شدگیِ ظریف جهان را به منظور شکل‌گیری حیات انسانی، شاهدی بر وجود خداوند تلقی می‌کند. بر خلاف باور رایج، استدلال تنظیم‌ظریف، در صورت‌بندی مرسوم، نه موفق است و نه خداباورانه. استدلال خواهم کرد که اگر تنظیم‌شدگی ظریف جهان بیشتر از حد مورد نیاز باشد، این حقیقتی نخواهد بود که خداباور مایل به استفاده از آن برای حجت آوردن له وجود خداوند باشد. از دید خداباور دو اشکال به استدلال تنظیم‌ظریف وارد (...) است: نخست، اشکال «زیاده‌روی»، که بیان می‌دارد این استدلال رویدادهای نامحتمل دیگری را نیز شاهدی بر وجود خدا تلقی می‌کند، که خداباور از آنها چنین تفسیری ندارد. دوم، اشکال «شلیک‌به‌خود»، که بیان می‌دارد استدلال تنظیم‌ظریف نقض‌غرض خداباور است. سوم، در استدلال تنظیم‌ظریف فرض شده است که به وقوع پیوستن رویدادی نامحتمل نیازمند تبیینی متفاوت نسبت به تبیین وقوع رویدادهای محتمل است، که پیشفرض نادرستی است و به اعتراض «خدای رخنه‌ها» دچار می‌شود. خداباور نیز مستقلاً این تمایز را نمی‌پذیرد. بنابراین، استدلال تنظیم‌ظریف مبتنی بر مفروضاتی است که با خداباوری، در معنای متعارف، سازگار نیست. (shrink)

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)

I provide an argument from consciousness for God’s existence. I first consider a version of the argument which is ultimately difficult to evaluate. I then consider a stronger argument, on which consciousness, given our worldly laws of nature, is rather substantial evidence for God’s existence. It is this latter argument the paper largely focuses on, both in setting it out and defending it from various objections.

A new formulation of the Fine-Tuning Argument (FTA) for the existence of God is offered, which avoids a number of commonly raised objections. I argue that we can and should focus on the fundamental constants and initial conditions of the universe, and show how physics itself provides the probabilities that are needed by the argument. I explain how this formulation avoids a number of common objections, specifically the possibility of deeper physical laws, the multiverse, normalisability, whether God would fine-tune at (...) all, whether the universe is too fine-tuned, and whether the likelihood of God creating a life-permitting universe is inscrutable. (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)

Why does God allow evil? One hypothesis is that God desires the existence and activity of free creatures but He was unable to create a world with such creatures and such activity without also allowing evil. If Molinism is true, what probability should be assigned to this hypothesis? Some philosophers claim that a low probability should be assigned because there are an infinite number of possible people and because we have no reason to suppose that such creatures will choose one (...) way rather than another. Arguments like this depend on the principle of indifference. But that principle is rejected by most philosophers of probability. Some philosophers claim that a low probability should be assigned because doing otherwise violates intuitions about freewill. But such arguments can be addressed through strategies commonly employed to defend theories with counterintuitive results across ethics and metaphysics. (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)

This paper explores early Australasian philosophy in some detail. Two approaches have dominated Western philosophy in Australia: idealism and materialism. Idealism was prevalent between the 1880s and the 1930s, but dissipated thereafter. Idealism in Australia often reflected Kantian themes, but it also reflected the revival of interest in Hegel through the work of ‘absolute idealists’ such as T. H. Green, F. H. Bradley, and Henry Jones. A number of the early New Zealand philosophers were also educated in the idealist tradition (...) and were influential in their communities, but produced relatively little. In Australia, materialism gained prominence through the work of John Anderson, who arrived in Australia in 1927, and continues to be influential. John Anderson had been a student of Henry Jones, who might therefore be said to have influenced both main strands of Australian philosophical thought. (shrink)

In this paper we propose that cosmological fine-tuning arguments, when levied in support of the existence of Intelligent Designers or Multiverses, are much less interesting than they are thought to be. Our skepticism results from tracking the distinction between merely epistemic or logical possibilities on one hand and nonepistemic possibilities, such as either nomological or metaphysical possibilities, on the other. We find that fine-tuning arguments readily conflate epistemic or logical possibilities with nonepistemic possibilities and we think that this leads to (...) treating the search for an explanation of fine-tuning as analogous to standard empirical theorizing about first-order nomological matters, when in fact the two investigational enterprises are profoundly different. Similar conflation occurs when fine-tuning arguments do not carefully distinguish between different interpretations of probabilities within the arguments. Finally, these arguments often rely on spatial analogies, which are often misleading precisely in that they encourage the conflation of epistemic and nonepistemic possibility. When we pay attention to the distinctions between merely epistemic versus nonepistemic modalities and probabilities, the extant arguments in favor of intelligent designers or multiverses, or even for the nonepistemic improbability of fine-tuning, consist of empirically unconstrained speculation concerning relevant nonepistemic modal facts. (shrink)

I consider whether evolutionary explanations can debunk our moral beliefs. Most contemporary discussion in this area is centred on the question of whether debunking implications follow from our ability to explain elements of human morality in terms of natural selection, given that there has been no selection for true moral beliefs. By considering the most prominent arguments in the literature today, I offer reasons to think that debunking arguments of this kind fail. However, I argue that a successful evolutionary debunking (...) argument can be constructed by appeal to the suggestion that our moral outlook reflects arbitrary contingencies of our phylogeny, much as the horizontal orientation of the whale’s tail reflects its descent from terrestrial quadrupeds. An introductory chapter unpacks the question of whether evolutionary explanations can debunk our moral beliefs, offers a brief historical guide to the philosophical discussion surrounding it, and explains what I mean to contribute to this discussion. Thereafter follow six chapters and a conclusion. The six chapters are divided into three pairs. The first two chapters consider what contemporary scientific evidence can tell us about the evolutionary origins of morality and, in particular, to what extent the evidence speaks in favour of the claims on which debunking arguments rely. The next two chapters offer a critique of popular debunking arguments that are centred on the irrelevance of moral facts in natural selection explanations. The final chapters develop a novel argument for the claim that evolutionary explanations can undermine our moral beliefs insofar as they show that our moral outlook reflects arbitrary contingencies of our phylogeny. A conclusion summarizes my argument and sets out the key questions that arise in its wake. (shrink)

We have known for a long time that there is complex, intelligent life. More recently we have discovered that the physics of our universe is fine-tuned so as to allow for the existence of such life. Call these two observations the Old Datum and the New Datum, respectively. Our question here is: once we know the Old Datum, does the New Datum provide additional evidence for the design hypothesis? I argue that it does not. Thus, there is an important sense (...) in which the much-touted fine-tuning of physics is irrelevant to debates about design. (shrink)

This paper examines probabilistic versions of the fine-tuning argument for design (FTA), with an emphasis on the interpretation of the probability statements involved in such arguments. Three categories of probability are considered: physical, epistemic, and logical. Of the three possibilities, I argue that only logical probability could possibly support a cogent probabilistic FTA. However, within that framework, the premises of the argument require a level of justification that has not been met, and, it is reasonable to believe, will not be (...) met anytime soon. (shrink)