In books such as The World Within the World and The Anthropic Cosmological Principle, astronomer John Barrow has emerged as a leading writer on our efforts to understand the universe. Timothy Ferris, writing in The Times Literary Supplement of London, described him as "a temperate and accomplished humanist, scientist, and philosopher of science--a man out to make a contribution, not a show." Now Barrow offers the general reader another fascinating look at modern physics, as he explores the (...) quest for a single, unifying theory that will unlock nature's secrets. Theories of Everything is more than a history of science, more than a popular report on recent research and discoveries. Barrow provides a reflective, intelligent commentary on what a true Theory of Everything would be--its ingredients, its limitations, and what it could tell us about the universe. Never before, he writes, have physicists been so confident and so eager in the hunt for this "cosmic Rosetta Stone," as he calls it: "a single all-embracing picture of all the laws of nature from which the inevitability of all things seen must follow with unimpeachable logic." He lays out eight essential ingredients for a Theory of Everything and then explores each in turn, tracing how our knowledge has developed and how scientific discovery relates to our changing philosophy and religious thought in each area. Some of these ingredients are obvious--the laws of nature must be explained, for example, as well as its organizing principles--but others may be surprising, such as broken symmetries and selection biases. A Theory of Everything must account for the fact that the universe is "messy and complicated," he tells us, and for the limitations imposed by the questions we ask and the information we can obtain. The key lies in the remarkable capacity of mathematics to express the fundamental workings of the physical world--a language that the human mind is uniquely equipped to understand and manipulate. Barrow examines what mathematics actually is and describes how it makes the universe intelligible and provides a path to the underlying coherence in nature--which has led, in fact, to arguments that the universe itself is a vast computer. Yet even the most complete theory, even the most comprehensive mathematical explanation, cannot account for the uncomputable varieties of human experience and thought. "No non-poetic account of reality," he writes, "can be complete." In a field where the authorities converse in equations and mathematical notations, John Barrow speaks with the voice of thoughtful and knowledgeable humanist. Written with eloquence and expertise, Theories of Everything establishes a new perspective on humanity's efforts to explain the universe. (shrink)

Ever since Copernicus, scientists have continually adjusted their view of human nature, moving it further and further from its ancient position at the center of Creation. But in recent years, a startling new concept has evolved that places it more firmly than ever in a special position. Known as the Anthropic Cosmological Principle, this collection of ideas holds that the existence of intelligent observers determines the fundamental structure of the Universe. In its most radical version, the Anthropic (...) Principle asserts that "intelligent information-processing must come into existence in the Universe, and once it comes into existence, it will never die out." This wide-ranging and detailed book explores the many ramifications of the Anthropic Cosmological Principle, covering the whole spectrum of human inquiry from Aristotle to Z bosons. Bringing a unique combination of skills and knowledge to the subject, John D. Barrow and Frank J. Tipler--two of the world's leading cosmologists--cover the definition and nature of life, the search for extraterrestrial intelligence, and the interpretation of the quantum theory in relation to the existence of observers. The book will be of vital interest to philosophers, theologians, mathematicians, scientists, and historians, as well as to anyone concerned with the connection between the vastness of the universe of stars and galaxies and the existence of life within it on a small planet out in the suburbs of the Milky Way. (shrink)

Carter’s anthropic principle reminds us that intelligent life can find itself only in life-permitting times, places or universes. The principle concerns a possible observational selection effect, not a designing deity. It has no special concern with humans, nor does it say that intelligent life is inevitable and common. Barrow and Tipler, who discuss all this, are not biologically ignorant. As argued in "Universes" (Leslie, 1989) they may well be right in thinking that "fine tuning" of force strengths and (...) particle masses, without which life would be impossible, proves the reality of God or else of multiple universes plus observational selection. (shrink)

John Leslie presents a thought experiment to show that chances are sometimes observer-relative in a paradoxical way. The pivotal assumption in his argument – a version of the weak anthropic principle – is the same as the one used to get the disturbing Doomsday argument off the ground. I show that Leslie's thought experiment trades on the sense/reference ambiguity and is fallacious. I then describe a related case where chances are observer-relative in an interesting way. But (...) not in a paradoxical way. The result can be generalized: At least for a very wide range of cases, the weak anthropic principle does not giverise to paradoxical observer-relative chances. This finding could be taken to give new indirect support to the doomsday argument. (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)

ABSTRACT Brandon Carter's anthropic principle reminds us that observers are most likely to find themselves in the spatiotemporal regions containing most of them. One should tend to prefer theories which make one's own observed spatiotemporal position fairly ordinary. This could much increase the estimated likelihood that our technological civilisation was not the very first in a universe which would include hugely many such civilisations. Similarly, which is the Carter‐Leslie ‘doomsday argument’, it could much increase the estimated likelihood that (...) you and I are not in the earliest 0.01%, for instance, of all humans who will ever have lived—as we would be if the human race survived for long even at its present size, let alone if it colonised the galaxy. With the aid of thought‐experiments, the article defends this argument against many objections. Other thought‐experiments suggest, though, that the argument is weaker if the world is radically indeterministic. In this case, it perhaps indicates only that we should not be highly confident in humankind's long survival, because high confidence would be equivalent to saying that any indeterminism would be unlikely to be relevant. (shrink)

John D. Barrow and Frank J. Tipler's recently published Anthropic Cosmological Principle is an encyclopedic defense of melioristic evolutionary cosmology. They review the history of the idea from ancient times to the present, and defend both a “weak” version, and two “strong” versions of the anthropic principle. I argue the weak version of the anthropic principle is true and important, but that neither of the two strong versions are well grounded in fact. Their “final” (...) class='Hi'>anthropic principle is a revision of Teilhard de Chardin's evolutionary cosmology. They rectify Teilhard's factual errors but commit even more serious psychological and religious errors of their own. (shrink)

The design argument for the existence of God took a probabilistic turn in the 17 th and 18 th centuries. Earlier versions, such as Thomas Aquinas' 5 th way, usually embraced the premise that goal-directed systems (things that "act for an end" or have a function) must have been created by an intelligent designer. This idea – which we might express by the slogan "no design without a designer" – survived into the 17 th and 18 th centuries, 1 and (...) it is with us still in the writings of many creationists. The new version of the argument, inspired by the emerging mathematical theory of probability, removed the premise of necessity. It begins with the thought that goal-directed systems might have arisen by intelligent design or by chance; the problem is to discern which hypothesis is more plausible. With the epistemic concept of plausibility characterized in terms of the mathematical concept of probability, the design argument was given a new direction. The new probabilistic perspective did not extinguish the older idea of "no design without a designer." The two conflicting approaches coexisted, often with less than perfect clarity about their fundamental difference. At the same time, the details of how the probabilistic perspective ought to be articulated were slow in emerging. These characteristics of uneven development are exemplified in a debate that took place in the 18 th century among three probabilists – John Arbuthnot, Nicholas Bernoulli, and Abraham DeMoivre – on the proper explanation of human sex ratio. Arbuthnot proposed a probabilistic version of the design argument, claiming that it is intelligent design, not chance, that provides the better explanation of why slightly more boys than girls are born each year. Bernoulli rejected Arbuthnot's argument. DeMoivre defended Arbuthnot against Bernoulli's criticisms. The problem of explaining sex ratio, both in human populations and in the rest of nature, experienced another transformation after 1859 --it became a problem for the theory of evolution by natural selection. Darwin (1871) addressed the question in the first edition of The Descent of Man but withdrew his suggestion in the second (Darwin 1874). Carl Düsing (1884) provided a mathematical model that moved beyond the explanation Darwin offered. Fisher (1930) added the new idea of parental expenditure. Williams (1966) argued that the sex ratios found in nature provide the opportunity to test hypotheses of group selection against hypotheses of individual selection. Hamilton (1967) constructed a model that generalizes Fisher's approach and represents the effects of both group and individual selection. The theory of natural selection gradually developed the ability to predict sex ratios, not just explain them post hoc. (shrink)

Suppose various observers are divided randomly into two groups, a large and a small. Not knowing into which group anyone has been sent, each can have strong grounds for believing in being in the large group, although recognizing that every observer in the other group has equally powerful reasons for thinking of this other group as the large one. Justified belief can therefore be observer-relative in a rather paradoxical way. Appreciating this allows one to reject an intriguing new objection against (...) Brandon Carter's 'doomsday argument'. Carter encourages us to doubt that we are among only the first hundredth, say, or first millionth, of all humans who will ever have existed. He thereby reinforces whatever reasons we may have for suspecting that, unless we take great care, the human race will not survive long. Admittedly his argument is weakened if our world is indeterministic, so that there is no suitably guaranteed 'fact of the matter' of how many humans will ever have existed. But even then, it can caution us against believing that a lengthy future for humankind 'is as good as determined'. Of all the objections the argument has yet faced, the new one is the most interesting. (shrink)

Recent discussions about the anthropic principle and the argument from design can perhaps be summarized as follows : The world is very unusual, so it must have been made by an intelligent creator. The world is very unusual, but unusual things do occur by chance. Both and , in their ordinary interpretations, have been labelled probabilistic fallacies. In my paper I will discuss in particular the following two aspects: The contemporary relevance of Cicero's discussions on chance. The fact that (...) any talk of chance events is only possible subject to the more encompassing idea of "limited belief in chance". (shrink)

Reconstructing the Past seeks to clarify and help resolve the vexing methodological issues that arise when biologists try to answer such questions as whether human beings are more closely related to chimps than they are to gorillas. It explores the case for considering the philosophical idea of simplicity/parsimony as a useful principle for evaluating taxonomic theories of evolutionary relationships. For the past two decades, evolutionists have been vigorously debating the appropriate methods that should be used in systematics, the field that (...) aims at reconstructing phylogenetic relationships among species. This debate over phylogenetic inference, Elliott Sober observes, raises broader questions of hypothesis testing and theory evaluation that run head on into long standing issues concerning simplicity/parsimony in the philosophy of science. Sober treats the problem of phylogenetic inference as a detailed case study in which the philosophical idea of simplicity/parsimony can be tested as a principle of theory evaluation. Bringing together philosophy and biology, as well as statistics, Sober builds a general framework for understanding the circumstances in which parsimony makes sense as a tool of phylogenetic inference. Along the way he provides a detailed critique of parsimony in the biological literature, exploring the strengths and limitations of both statistical and nonstatistical cladistic arguments. (shrink)

The purpose of this paper is to analyze the theoretical commitments of autopoietic enactivism in relation to Errol E Harris’s dialectical holism in the interest of establishing a common metaphysical ground. This will be undertaken in three stages. First, it is argued that Harris’s reasoning provides a means of developing enactivist ontology beyond discussions limited to cognitive science and into domains of metaphysics that have traditionally been avoided by phenomenologists. Here, I maintain enactivist commitments are consistent with Harris’s reasoning from (...) certain synthetic a priori first principles, to his derivation of a teleological anthropic principle, which asserts the necessity of consciousness within the cosmos. Second, it is proposed that Steven Rosen’s long-standing proposal for a topology of phenomenology may provide a common logical foundation for both Harris and enactivists regarding anthropic reasoning. Third, it is argued that a pragmatic approach to process ontology is the most rigorous way of responding to the realism/anti-realism concerns that inevitably follow. If successful, this work will update Harris’s arguments with contemporary scientific and philosophical terminology and extend enactivism from philosophy of mind, into a general phenomenological ontology. (shrink)

Elliott Sober has recently argued that the cosmological design argument is unsound, since our observation of cosmic fine-tuning is subject to an observation selection effect (OSE). I argue that this view commits Sober to rejecting patently correct design inferences in more mundane scenarios. I show that Sober's view, that there are OSEs in those mundane cases, rests on a confusion about what information an agent ought to treat as background when evaluating likelihoods. Applying this analysis to the design (...) argument shows that our observation of fine-tuning is not rendered uninformative by an OSE. Design and the Anthropic Objection Previous responses to the Anthropic Objection Variations: experimental squads and survivor reunions Why there is no OSE in firing squad cases Application to the design argument. (shrink)

The design argument is one of three main arguments for the existence of God; the others are the ontological argument and the cosmological argument. Unlike the ontological argument, the design argument and the cosmological argument are a posteriori. And whereas the cosmological argument could focus on any present event to get the ball rolling (arguing that it must trace back to a first cause, namely God), design theorists are usually more selective.

This article focuses on the Omega Point, an essential concept in Teilhard de Chardin’s evolutionary metaphysics. In certain passages about the Omega Point, Teilhard mentions the primeval atom hypothesis, a theory about the beginning of the universe proposed by Georges Lemaître, another contemporary Jesuit priest who was also a scientist. Although Teilhard and Lemaître are essentially evolutionists, besides being Jesuit priests, their evolutionary metaphysics and their philosophies of science are radically divergent, and two important differences are presented here – about (...) the eventual cosmic determinism and about the relationship between scientific knowledge and religious beliefs. This article also shows how Teilhard’s original concept was projected into two cosmological theories in which it reveals an essential transfiguration by losing its initial anthropic and religious matrix – the cosmological anthropic principle, proposed by physicists John Barrow and Frank Tipler, and the Omega Point Theory proposed later by Frank Tipler. (shrink)

Cosmologists using the Anthropic Principle claim that if our universe had been much different then nobody would exist to observe it. This may become explanatory when one accepts the actual existence of multiple "universes": gigantic, largely or entirely separate systems having very varied properties. Ian Hacking has urged, though, that an Inverse Gambler's Fallacy is committed during many attempts to formulate anthropic explanations. Besides disagreeing with him, the paper makes several further points in support of such explanations, in (...) particular against the background of the Inflationary Universe. (shrink)

Evolutionary gradualism, the randomness of mutations, and the hypothesis that natural selection exerts a pervasive and substantial influence on evolutionary outcomes are pair-wise logically independent. Can the claims about selection and mutation be used to formulate an argument for gradualism? In his Genetical Theory of Natural Selection, R.A. Fisher made an important start at this project in his famous “geometric argument” by showing that a random mutation that has a smaller effect on two or more phenotypes will have a higher (...) average fitness than a random mutation that has a larger phenotypic effect. Motoo Kimura’s demonstration that a gene’s probability of fixation depends on both the selection coefficient and the effective population size shows that Fisher’s argument for gradualism was mistaken. Here we analyze Fisher’s argument and explain how Kimura’s theory leads to a conclusion that Fisher did not anticipate. We identify a fallacy that reasoning about fitness differences and their evolutionary consequences should avoid. We then distinguish forward-directed from backward-directed versions of gradualism. The backward-directed thesis about a single mutation may be correct, but the forward-directed thesis is not. After that we consider a sequence of random mutations that all affect the same cluster of phenotypes and Allen Orr’s idea that there is an optimal sequence of mutation sizes, moving from larger to smaller as the population approaches a fixed optimum. This provides a likelihood justification for a forward-directed version of gradualism when there is a fixed optimum, but it also provides an argument against forward-directed gradualism if the optimum shifts substantially as the population evolves. Finally, we consider whether genome-wide association studies (GWASs) can furnish empirical evidence that bears on the truth of gradualism. The version of gradualism that GWASs directly bear on concerns the phenotypic effect size of a gene after it arises by mutation and has reached an appreciable frequency, not the phenotypic size of the mutation event itself. (shrink)

Cosmologists often claim that our universe is “fine tuned” for life. A change by 1% in the strong nuclear force would have meant little carbon would exist, and carbon can seem biologically essential. Again, the riches of chemistry and biochemistry depend on the neutron’s being heavier than the proton by no more than 0.1%. The early cosmic expansion rate may have needed fine tuning to one part in l055 to prevent speedy recollapse and speedy disintegration. To prevent excess turbulence the (...) “smoothness” perhaps needed fine tuning to one part in 10 raised to the power of 10123 (a number far greater than 101230). Etcetera (Leslie 1982, 1983a, 1985, 1986).The list of such claims is very long. No doubt some of its items are mistakes. Others may be dictated by basic physics so that they are not fine-tunable. (shrink)

The cosmos exists just because of the ethical need for it We, and all the intricate structures of our universe, exist as thoughts in a divine mind that knows everything worth knowing. There could also be infinitely many other universes in this mind....It may be hard to believe that the universe is as Leslie says it is--but it is also hard to resist his compelling ideas and arguments.

The properties, theoretical magnitudes, and natural kinds which science seeks to characterize, and not the sense or meanings which parts of speech may possess, are the subject of this paper. Many philosophers (e.g., Putnam [1971] and Achinstein [1974]) have agreed that two predicates of different meaning may pick out the same property, but they usually hold that that logically equivalent predicates must pick out the same properties. I propose to deny this thesis. My argument is by way of an example (...) and by appeal to a principle. The principle connects propertyhood with causal efficacy. The example situation I will describe in what follows is intended to show that the property of being a closed straight-sided figure having three sides is not the same property as that of being a closed straight-sided figure having three angles (a triangle). (shrink)

What thesis is Hume trying to establish in his essay “On Miracles” and does he succeed? John Earman’s answer to the latter question is clearly conveyed by the title of his new book. Earman uses a Bayesian representation of the problem to make his case. For Earman, this mode of analysis is both perspicuous and nonanachronistic, in that probability reasoning was central to the 18th century debate about miracles in particular and testimony in general. Indeed, one of Hume’s most (...) interesting antagonists, Richard Price, was the person to whom Thomas Bayes entrusted his now-famous essay for posthumous publication. For Earman, Price is the proper Bayesian, while Hume’s essay provides only “rhetoric and schein geld”. Earman’s tone is consistently prosecutorial and sometimes snide; he says that his animus is not so much against Hume himself as against those who smugly invoke Hume’s essay as definitively settling the matter. This tone should not deter potential readers who are convinced that Hume’s essay contains something of value. Earman’s book is interesting and provocative in multiple ways—it places Hume’s essay in its historical setting, it offers an insightful close reading of the text, and it shows how the resources of Bayesianism can be powerfully put to work. Besides Earman’s own essay, the volume also contains Hume’s essay and relevant work by others, including Locke, Spinoza, Samuel Clarke, Price, Laplace, and Babbage. The book would be an excellent choice for an advanced undergraduate or graduate seminar. (shrink)

Solipsism poses a familiar epistemological problem. Each of us has beliefs about a world that allegedly exists outside our own minds. The problem is to justify these nonsolipsistic convictions. One standard approach is to argue that the existence of things outside our own sensations may reasonably be inferred from regularities that obtain within our sensations. Certain experiences, which I will call tiger sounds and tiger visual images, exhibit a striking correlation. We can explain the existence of this correlation by postulating (...) an entity that is a cause of both. If there were tigers, it would be no surprise that certain sights and certain sounds tend to co-occur. Our rejection of solipsism can thus be justified by appeal to an abductive argument; we advance an inference to the best explanation conforming to the pattern that Reichenbach called the principle of the common cause. (shrink)

John Beatty (1995) and Alexander Rosenberg (1994) have argued against the claim that there are laws in biology. Beatty's main reason is that evolution is a process full of contingency, but he also takes the existence of relative significance controversies in biology and the popularity of pluralistic approaches to a variety of evolutionary questions to be evidence for biology's lawlessness. Rosenberg's main argument appeals to the idea that biological properties supervene on large numbers of physical properties, but he also (...) develops case studies of biological controversies to defend his thesis that biology is best understood as an instrumental discipline. The present paper assesses their arguments. (shrink)

The positivists suggest that some truths may be immune from empirical refutation and yet lacking in rational justification. Quine holds that every proposition is in principle empirically refutable so there are no a priori truths. I’ll provide a working characterization of the idea of “rational revisability” and argue it’s impossible for us to take a chain of rational revision and end up revising everything which we now believe. Quine's position on revisability is also in tension with certain theses about epistemic (...) holism. Finally, I discuss a more general context in which rational argument is viewed as one mechanism among many for reliably modifying beliefs. This more biological perspective allows us to formulate Quine's claims about revisability in a new way and to raise some interesting questions about the potential impact of natural selection on our cognitive capacities. (shrink)

Evidence and Evolution has four chapters: (1) Evidence, (2) Intelligent Design, (3) Natural Selection, and (4) Common Ancestry. The first chapter develops tools that are used in the rest of the book, though more ideas about evidence are added. In Chapter 1, I endorse a pluralistic outlook—Bayesianism is fine in some inference problems, likelihoodism in others, and AIC in still others. In Chapter Two, on intelligent design, I try to develop the strongest possible formulation of the design argument for the (...) existence of God, after which I criticize the argument so conceived. This second chapter also attempts to resuscitate the concept of testability. Chapter 3, on natural selection, discusses how to evaluate competing hypotheses on evolution mechanisms and evaluate the use of the principle of common cause, molecular data, and cladistic parsimony. Chapter 4 is on common ancestry: what it means to say that all life on earth has a common ancestor, and s. Why should the similarity of two species be evidence that they have a common ancestor? The chapter concludes with a discussion of how biologists use cladistic parsimony to infer phylogenetic trees and compare it with explicit statistical approaches. (shrink)

Solipsism poses a familiar epistemological problem. Each of us has beliefs about a world that allegedly exists outside our own minds. The problem is to justify these nonsolipsistic convictions. One standard approach is to argue that the existence of things outside our own sensations may reasonably be inferred from regularities that obtain within our sensations. Certain experiences, which I will call tiger sounds and tiger visual images, exhibit a striking correlation. We can explain the existence of this correlation by postulating (...) an entity that is a cause of both. If there were tigers, it would be no surprise that certain sights and certain sounds tend to co-occur. Our rejection of solipsism can thus be justified by appeal to an abductive argument; we advance an inference to the best explanation conforming to the pattern that Reichenbach called the principle of the common cause. (shrink)

Do the methods of science lead to atheism? This is different from asking whether the results of science (e.g., well‐confirmed theories in evolutionary biology or cosmology) have that consequence. In this chapter, I consider several philosophical theories about scientific reasoning and trace out their implications for atheism, theism, and agnosticism. These theories include different versions of empiricism, logical positivism, inference to the best explanation, Bayesianism, hypothetico‐deductivism, and the principle of parsimony (Ockham's razor).

Biological knowledge has increased exponentially in the last century or so, and it would be surprising if some of this knowledge did not have implications for philosophy. In contrast with a good deal of Elliott Sober's best known work, which aims to bring philosophical methods to bear on issues within biology, the theme of this collection of essays is to explore some ways in which biological ideas, or more specifically evolutionary ideas, may be brought to bear on philosophical issues. (...) Sober notes in his Introduction that there is no systematic theme beyond the attempt to explore the philosophical implications of taking evolutionary biology seriously. And certainly this is a diverse collection, especially with regard to the extent to which the various arguments of these papers depend on any particular content to evolutionary claims. (shrink)

Are we in imminent danger of extinction? Yes, we probably are, argues John Leslie in his chilling account of the dangers facing the human race as we approach the second millenium. The End of the World is a sobering assessment of the many disasters that scientists have predicted and speculated on as leading to apocalypse. In the first comprehensive survey, potential catastrophes - ranging from deadly diseases to high-energy physics experiments - are explored to help us understand the (...) risks. One of the greatest threats facing humankind, however, is the insurmountable fact that we are a relatively young species, a risk which is at the heart of the 'Doomsday Argument'. This argument, if correct, makes the dangers we face more serious than we could have ever imagined. This more than anything makes the arrogance and ignorance of politicians, and indeed philosophers, so disturbing as they continue to ignore the manifest dangers facing future generations. (shrink)

The argument from design is best understood as a likelihood inference. Its Achilles heel is our lack of knowledge concerning the aims and abilities that the putative designer would have; in consequence, it is impossible to determine whether the observations are more probable under the design hypothesis than they are under the hypothesis of chance. Hypotheses about the role played by natural selection in the history of life also can be evaluated within a likelihood framework, and here too there are (...) auxiliary assumptions that need to be in place if the likelihoods of selection and chance are to be compared. I describe some problems that arise in connection with the project of obtaining independent evidence concerning those auxiliary assumptions. (shrink)

This paper is an essay review of John Earman's book,\nHume's Abject Failure--the Argument against Miracles\n(Oxford University Press, New York, 2000). Earman is very\ncritical of Hume's famous argument about miracles, I am\nmore sympathetic, though I grant that Earman makes many\ngood critical points. Earman's method of analysis is\nBayesian, as is mine.

Studies in astrophysical cosmology have served to reveal the incomprehensible fine-tuning of the fundamental constants and cosmological quantities which must obtain if a universe like ours is to be life-permitting. Traditionally, such fine-tuning of the universe for life would have been taken as evidence of divine design. William Dembski’s ’generic chance elimination argument’ provides a framework for evaluating the hypothesis of design with respect to the fine-tuning of the universe. On Dembski’s model the key to a design inference is (...) the elimination of the competing alternatives of physical necessity and chance. In debates over fine-tuning, the former is represented by a ’theory of everything’, which would eliminate or significantly reduce the improbabilities of fine-tuning. The latter takes the shape of the ’many worlds hypothesis’, according to which a ’world ensemble’ of universes exist, thus providing purchase for the ’anthropic principle’. This paper assesses the relative merit. (shrink)

What force has the Argument from Design—the attempt to argue to Design, and hence to God, from various alleged signs of it in Nature? Some preliminary points. First: To establish the reality of God need not be to prove that there exists an actual person meriting that name. Many theologians, for example P. Tillich, have denied that God is any manner of existent. On a fairly simple and attractive interpretation, their view is that ‘God’ names the principle that ethical requirements (...) are creatively powerful. In previous papers I tried to make sense of this principle: there is much that can be said for it. So when talking of ‘design’ I am not presupposing anything as specific as an actual designer. (shrink)

A modern assessment of the classical Boltzmann-Schuetz argument for large-scale entropy fluctuations as the origin of our observable cosmological domain is given.The emphasis is put on the central implication of this picture which flatly contradicts the weak anthropic principle as an epistemological statement about the universe. Therefore, to associate this picture with the anthropic principle as it is usually done is unwarranted. In particular, Feynman's criticism of theanthropic principle based on the entropy-fluctuation picture is a product of (...) this semantic confusion. (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)

A synchronic probability is the probability at a time that an outcome occurs at that very time. Common sense invokes synchronic probabilities with values between 0 and 1, as do scientific theories such as classical statistical mechanics. Recently, philosophers have argued about whether any synchronic probabilities are best interpreted as objective chances. I add to this debate an underappreciated reason we might have to believe in synchronic chance; it might turn out that the best interpretation of our common sense and (...) scientific theories is one in which the macrophysical properties of physical systems are partly determined by synchronic chance distributions over microphysical properties of those systems. Additionally, I argue against the common charge that synchronic probability fails to satisfy various platitudes about chance—most notably Lewis’s Principal Principle. (shrink)

If it survives for a little longer, the human race will probably start to spread across its galaxy. Germ warfare, though, or environmental collapse or many another factor might shortly drive humans to extinction. Are they likely to avoid it? Well, suppose they spread across the galaxy. Of all humans who would ever have been born, maybe only one in a hundred thousand would have lived as early as you. If, in contrast, humans soon became extinct then because of the (...) population explosion you would have been 'fairly ordinary'. Roughly ten per cent of all humans would have been your contemporaries. Now (as the cosmologist Brandon Carter saw to his dismay) a scientific principle tells us not to treat observations as highly extraordinary when they could easily be fairly ordinary. How to apply the principle is controversial, yet it seems we can safely conclude that humanity's chances of galactic colonization cannot be high. Still, we should work to make them as high as possible, resisting those philosophers who argue that human extinction would be no tragedy. (shrink)

A common type of argument against the existence of God is to argue that certain essential features associated with the existence of God are inconsistent with certain other features to be found in the actual world. for an analysis of the different ways to deploy the term “God” in philosophical and theological discourse and for an analysis of the logical form of arguments for and against the existence of God.) A recent example of this type of argument against the existence (...) of God is based on the assumption that there are random processes or chancy states of affairs in the actual world that contradict God being absolute sovereign over his creation: Chancy states of affairs are said to entail a denial of divine providence or omniscience. argues that “classical Big Bang cosmology is inconsistent with theism due to the unpredictable nature of the Big Bang singularity.”) More often than not, however, this apparent conflict is formulated only intuitively and lacks sufficient conceptual clarification of the crucial terms involved. As a consequence, it is seldom clear where the conflict really lies. In what follows, I first provide a brief analysis of chance and randomness before I turn to cosmological and evolutionary arguments against the existence of God that in some way or other are based on chance and randomness. I end by way of comparing three popular conceptions of God as regards their ability to deal with God’s relation to a world of chance and randomness. Neither classical theism, nor open theism, nor indeed process panentheism has difficulties in accounting for God’s relation to a world of chance and randomness. (shrink)

The structure of the universe and of most objects in it is determined by a small number of physical constants. It can be shown that only a limited range of values for each of these constants is compatible with the existence of human life. The fact that we are able to exist--but just barely--calls for an explanation. In the last fifteen years, an "anthropic principle" has been proposed as a possible scientific explanation of the fortuitous features of our world. (...) This type of explanation focuses on ways in which the presence of human beings guarantees that conditions in the early universe be suitable for the eventual development of intelligent life. In its strongest form, the anthropic principle is teleological: the universe is habitable precisely so that humans can evolve in it. ;Many issues surrounding the principle and its role in contemporary cosmology have been widely misunderstood by physicists and philosophers alike. My project is to clarify the nature of the principle and to criticize its value as a scientific claim. In chapters 1 and 2, I discuss the principle's historical background, and differentiate between several distinct ideas often misleadingly categorized as "anthropic." In chapter 3, after considering the principle's scientific justification, I conclude that it is neither essentially anthropic nor capable of predictive success. In chapter 4, I argue that the principle has little, if any, explanatory power, even in its teleological form. Having put fourth a number of criticisms of the principle as a scientific principle, in the final chapter I look at the possibility of construing it in a theistic context. Although the principle is not usually considered a religious principle, its resemblance to premises used in traditional theistic arguments from design suggests that it may be more defensible if thought of in a theistic context. (shrink)

John Barrow is increasingly recognized as one of our most elegant and accomplished science writers, a brilliant commentator on cosmology, mathematics, and modern physics. Barrow now tackles the heady topic of impossibility, in perhaps his strongest book yet. Writing with grace and insight, Barrow argues convincingly that there are limits to human discovery, that there are things that are ultimately unknowable, undoable, or unreachable. He first examines the limits on scientific inquiry imposed by the deficiencies of the human mind: (...) our brain evolved to meet the demands of our immediate environment, Barrow notes, and much that lies outside this small circle may also lie outside our understanding. Barrow investigates practical impossibilities, such as those imposed by complexity, uncomputability, or the finiteness of time, space, and resources. Is the universe finite or infinite? Can information be transmitted faster than the speed of light? The book also examines the deeper theoretical restrictions on our ability to know, including Godel's theorem--which proved that there were things that could not be proved--and Arrow's Impossibility theorem about democratic voting systems. Finally, having explored the limits imposed on us from without, Barrow considers whether there are limits we should impose upon ourselves. For instance, if the secrets of the atom are to be found only by recreating extreme environments at great financial cost, just how much should we devote to that quest? Weaving together this intriguing tapestry, he illuminates some of the most profound questions of science, from the possibility of time travel to the very structure of the universe. (shrink)

The fundamental constants and initial conditions of the universe seem "finely tuned" for human habitation. The anthropic principle attempts to explain this fine tuning in terms of the eventual development of intelligent life. A closer look at the principle’s explanandum, however, reveals that it is teleologically and anthropocentrically biased. Our ignorance of the physical requirements of nonhuman forms of life forces the principle to be more unjustifiably anthropocentric and more speculative than is commonly admitted. Leslie’s, Barrow’s and Tipler’s (...) attempts to avoid an overly anthropocentric anthropic principle fail to solve these problems. (shrink)

Will we ever discover a single scientific theory that explains everything that has ever happened and everything that will happen - a key that unlocks the ...

_Anthropic Bias_ explores how to reason when you suspect that your evidence is biased by "observation selection effects"--that is, evidence that has been filtered by the precondition that there be some suitably positioned observer to "have" the evidence. This conundrum--sometimes alluded to as "the anthropic principle," "self-locating belief," or "indexical information"--turns out to be a surprisingly perplexing and intellectually stimulating challenge, one abounding with important implications for many areas in science and philosophy. There are the philosophical thought experiments and (...) paradoxes: the Doomsday Argument; Sleeping Beauty; the Presumptuous Philosopher; Adam & Eve; the Absent-Minded Driver; the Shooting Room. And there are the applications in contemporary science: cosmology ; evolutionary theory ; the problem of time's arrow ; quantum physics ; game-theory problems with imperfect recall ; even traffic analysis. _Anthropic Bias_ argues that the same principles are at work across all these domains. And it offers a synthesis: a mathematically explicit theory of observation selection effects that attempts to meet scientific needs while steering clear of philosophical paradox. (shrink)

_Anthropic Bias_ explores how to reason when you suspect that your evidence is biased by "observation selection effects"--that is, evidence that has been filtered by the precondition that there be some suitably positioned observer to "have" the evidence. This conundrum--sometimes alluded to as "the anthropic principle," "self-locating belief," or "indexical information"--turns out to be a surprisingly perplexing and intellectually stimulating challenge, one abounding with important implications for many areas in science and philosophy. There are the philosophical thought experiments and (...) paradoxes: the Doomsday Argument; Sleeping Beauty; the Presumptuous Philosopher; Adam & Eve; the Absent-Minded Driver; the Shooting Room. And there are the applications in contemporary science: cosmology ; evolutionary theory ; the problem of time's arrow ; quantum physics ; game-theory problems with imperfect recall ; even traffic analysis. _Anthropic Bias_ argues that the same principles are at work across all these domains. And it offers a synthesis: a mathematically explicit theory of observation selection effects that attempts to meet scientific needs while steering clear of philosophical paradox. (shrink)