_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)

The questions that were purely in the realms of philosophy are now beginning to be answered by science. The second Venice Conference on Cosmology and Philosophy explores the anthropic principle which states that the Universe has the conditions we observe because we are here. Out of all possible universes we can only experience the restricted class that permits observers. This realization has profound implications for cosmology, philosophy and theology; all of which are explored in this book by (...) thirteen contributors who gathered to discuss and share their theories within the context of science. The result is a unique collection of papers of great value to professional astronomers and philosophers interested in the role of observers in the Universe. (shrink)

The successes scored by the big bang model of cosmic evolution in the 1960’s led to an intensive application of quantum theory to the problem of how the expansion might have begun and what its likely first stages were. It seemed as though an incredibly precise setting of the initial conditions would have been needed in order that a long-lived galactic universe containing heavy elements might develop. One response was to suppose that the fine-tuning could somehow be explained by the (...) presence of humans in the universe. This ran quite counter to the traditional supposition, according to which an initial "chaos" was sufficient. This essay outlines the history of the two principles, argues that the so-called "weak" anthropic principle is banal, distinguishes between two sorts of anthropic explanation, and assesses the prospects of the anthropic turn in cosmology. (edited). (shrink)

The anthropic principle, that the universe exists in some sense for life, has persisted in recent religious and scientific thought because it derives from cosmological fact. It has been unsuccessful in furthering our understanding of the world because its advocates tend to impose final metaphysical solutions onto what is a physical problem. We begin by outlining the weak and strong versions of the anthropic principle and reviewing the discoveries that have led to their formulation. We present the reasons (...) some have given for ignoring the anthropic implications of these discoveries and find these reasons wanting—a real phenomenon demands real investigation. Theological and scientific solutions of the problem are then considered and criticized; these solutions provide dead ends for explanation. Finally, we pursue the path that explanation must follow and look at the physical details of the problem. It seems clear that the anthropic principle has been poorly framed. Removing the ambiguities surrounding the meaning of “life” may lead to more profitable investigations. (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)

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)

The Anthropic Principle suggests that the universe may have been designed for human life. This anthropocentric, anti-Copernican, notion elicits a variety of responses from scientists, including some elaborate attempts to invalidate it by trying to show that there may be an infinity of alternative universes. These attempts may be challenged as unreasonably speculative and presumptive. What emerges is the suggestion that cosmology may at last be in possession of some raw material for a postmodern creation myth. If the (...) Anthropic Principle can be integrated with biological explanations of human origins, and the result joined to the traditional Biblical Creation story, what emerges is a possible recovery of a religiously traditional, yet scientifically coherent, creation story for our generation. (shrink)

THE SAME PHILOSOPHICAL IDEAS often become the object of extremely diverse opinions. When Leibniz presented his idea of "possible worlds," Voltaire used the occasion for an ironic comment on "metaphysico-theologo-cosmology," whereas for P. L. M. de Maupertuis it was an idea that inspired his important discoveries in the domain of mathematical analysis of dynamic systems. Similar differences of opinion appear today in discussions on the so-called Anthropic Principle. Unequivalent variants of this principle state the existence of close links (...) between the appearance of carbon-based life and the cosmological structure of the universe, between the laws of cosmic evolution and values of physical constants. Many authors question the philosophical significance of the Anthropic Principle, regarding the principle as the product of arbitrary speculations. Their philosophical opponents try to show that certain versions of the principle, which do not go beyond generalization of empirical data, provide grounds for solid teleological assertions claiming that the appearance of the human observer is the goal of cosmic evolution. (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)

Complexity and life as we know it depend crucially on the laws and constants of nature as well as the boundary conditions, which seem at least partly “fine-tuned.” That deserves an explanation: Why are they the way they are? This essay discusses and systematizes the main options for answering these foundational questions. Fine-tuning might just be an illusion, or a result of irreducible chance, or nonexistent because nature could not have been otherwise (which might be shown within a fundamental theory (...) if some constants or laws could be reduced to boundary conditions or boundary conditions to laws), or it might be a product of selection: either observational selection (weak anthropic principle) within a vast multiverse of many different realizations of physical parameters, or a kind of cosmological natural selection making the measured parameter values quite likely within a multiverse of many different values, or even a teleological or intentional selection or a coevolutionary development, depending on a more or less goal-directed participatory contribution of life and intelligence. In contrast to observational selection, which is not predictive, an observer-independent selection mechanism must generate unequal reproduction rates of universes, a peaked probability distribution, or another kind of differential frequency, resulting in a stronger explanatory power. The hypothesis of Cosmological Artificial Selection (CAS) even suggests that our universe may be a vast computer simulation or could have been created and transcended by one. If so, this would be a far-reaching answer – within a naturalistic framework! – of fundamental questions such as: Why did the big bang and fine-tunings occur, what is the role of intelligence in the universe, and how can it escape cosmic doomsday? This essay critically discusses some of the premises and implications of CAS and related problems, both with the proposal itself and its possible physical realization: Does CAS deserve to be considered as a convincing explanation of cosmic fine-tuning? Is life incidental, or does CAS revalue it? And are life and intelligence ultimately doomed, or might CAS rescue them? (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)

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.

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” 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)

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 Anthropic Principle, in use by physicists, astronomers, and cosmologists, is currently under consideration by philosophers. This principle, in its various forms, appeals to man's existence as a constraint on our determination of natural laws and natural constants, as a principle of prediction, and, in its strongest form, as a principle of explanation which sanctions an argument for the universe being a product of design. What I shall endeavour to show here is how this principle, in its various forms, (...) is used in furthering our understanding of cosmology, and why this principle cannot be used as a principle of explanation. (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)

The claims of some authors to have introduced a new type of explanation in cosmology, based on the anthropic principle, are examined and found wanting. The weak anthropic principle is neither anthropic nor a principle. Either in its direct or in its Bayesian form, it is a mere tautology lacking explanatory force and unable to yield any prediction of previously unknown results. It is a pattern of inference, not of explanation. The strong anthropic principle is (...) a gratuitous speculation with no other support than previous religious commitment or the assumption of an actual infinity of universes, for which there is no the slightest empirical hint. But even assuming so much, it does not work. In particular, the assumption of an infinity of different universes is no guarantee of finding among them one like this one. The loose anthropic way of reasoning does not stand up to the usual methodological standards of empirical science. And it does not signal any anthropocentric turn in contemporary science. (shrink)

This paper deals with one of the basic philosophical questions in modern cosmology: can the so-called Anthropic Principle , considered as an alternative to the classical teleology of creation, be an adequate explanation of the evidence that our universe is fine-tuned for the emergence of life and consciousness. The main problem with this principle is not its presumed teleology, as it is sometimes wrongly supposed, but quite the contrary: its intention to avoid teleological explanations by including the existence (...) of many universes ( multiverse ) into extended cosmological models. After having compared logical and cosmological many-worlds concepts, this paper reaches the conclusion that the ontological reality of the multiverse is an even more problematic presupposition than some properly revised version of teleological causality. This in itself does not imply the classical theistic explanation of creation, since it also yields a pantheistic explanation of the emergence of life and consciousness in our universe. (shrink)

In Cosmos and Theos Professor Errol E. Harris develops the theological, ethical, and social implications of the Anthropic Cosmological Principle. He argues that the twentieth-century revolution in physics reinstates the traditional arguments for the existence of God that had been inevitably invalidated by the logic appropriate to Empiricism and the presuppositions of Newtonian science. Errol E. Harris stresses that the holism of contemporary science now demands a new dialectical logic and metaphysic, in the light of which old doctrines assume (...) a new aspect and gain fresh vitality. Professor Harris reviews the history of religion in relation to contemporary developments in science, contending that the conflict between the two, persistent since the seventeenth century, is largely the effect of the Copernican-Newtonian scientific paradigm rather than of any insuperable divergence of aim or dogma. He also reviews the salient arguments--and the criticism of them--that have been offered in the history of Western philosophy for God's existence. Cosmos and Theos concludes with a reinterpretation of Christian doctrine, intended to demonstrate the essential congruity between its tenets and the current conceptions of the Anthropic Principle. (shrink)

The phenomenon of philosophizing scientists is well known in the twentieth century literature; one need mention only Arthur Eddington, James Jeans or Edmund Whittaker. Even the wide spread of neopositivistic ideology was not able to stop the best among scientists from publicly expressing their philosophical views. The writings of Einstein, Schrodinger, Heisenberg and of many other outstanding physicists have significantly shaped our way of understanding the Universe and our place in it. The fall of neopositivism and recent advances in theoretical (...) physics, which seem to touch extremities of the empirical method and to demand some sort of philosophical justification, have strengthened this tendency. The gap between philosophy and science may not exist any longer, but the gap between philosophers and scientists continues to exercise its deplorable influence on science and philosophy. The book by Barrow and Tipler testifies to both of these things: it shows how the far-reaching horizons of modern physics and cosmology could be open for philosophical thinking, and simultaneously it demonstrates how this thinking, when done by physicists, is far away from that to which professional philosophers are accustomed. I. (shrink)

Harris elucidates the important philosophical implications of the Anthropic Principle. Tracing the continuous development of the principle from physics through biology and psychology, he examines the case for the thesis that intelligent life is necessarily involved from the very beginning of physical reality and that the entire process of natural evolution comes to consciousness of itself in the human mind.

This sequel to the highly acclaimed Cosmos and Anthropos demonstrates the impact on social, ethical, and theological doctrines of the twentieth-century scientific revolution, particularly the Anthropic Principle. Harris reviews the main arguments put forward in the Western philosophical tradition for the existence of God, as well as the critique of those arguments, and shows that the conflict between religion and science since the seventeenth century has resulted more from the implications of the Copernican-Newtonian scientific paradigm than from any insuperable (...) divergence of dogma or ultimate aim. (shrink)

Anthropic arguments in multiverse cosmology and string theory rely on the weak anthropic principle (WAP). We show that the principle, though ultimately a tautology, is nevertheless ambiguous. It can be reformulated in one of two unambiguous ways, which we refer to as WAP_1 and WAP_2. We show that WAP_2, the version most commonly used in anthropic reasoning, makes no physical predictions unless supplemented by a further assumption of "typicality", and we argue that this assumption is both (...) misguided and unjustified. WAP_1, however, requires no such supplementation; it directly implies that any theory that assigns a non-zero probability to our universe predicts that we will observe our universe with probability one. We argue, therefore, that WAP_1 is preferable, and note that it has the benefit of avoiding the inductive overreach characteristic of much anthropic reasoning. (shrink)

This sequel to the highly acclaimed "Cosmos and Anthropos" demonstrates the impact on social, ethical, and theological doctrines of the twentieth-century scientific revolution, particularly the Anthropic Principle. Harris reviews the main arguments put forward in the Western philosophical tradition for the existence of God, as well as the critique of those arguments, and shows that the conflict between religion and science since the seventeenth century has resulted more from the implications of the Copernican-Newtonian scientific paradigm than from any insuperable (...) divergence of dogma or ultimate aim. (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)

Fr. Ernan McMullin wrote at least five essays in which anthropic reasoning in cosmology was a prominent topic of discussion and evaluation. Unlike thewritings of many passionate advocates and hostile critics of the so-called “anthropic principle” (AP), they are all nuanced essays—very much in keeping with Fr. Ernan’s usual approach to difficult and controversial subjects. Supporters of that approach will praise what he has to say as properly cautious and circumspect; others will likely find him often indecisive. (...) In this essay, I will indicate why, while I largely agree with the first group of readers, I am nevertheless sympathetic to the concerns of the latter group. (shrink)

This paper deals with one of the basic philosophical questions in modern cosmology: can the so-called “Anthropic Principle”, considered as an alternative to the classical teleology of creation, be an adequate explanation of the evidence that our universe is “fine-tuned” for the emergence of life and consciousness. The main problem with this principle is not its presumed teleology, as it is sometimes wrongly supposed, but quite the contrary: its intention to avoid teleological explanations by including the existence of (...) many universes (“multiverse”) into extended cosmological models. After having compared logical and cosmological many-worlds concepts, this paper reaches the conclusion that the ontological reality of the “multiverse” is an even more problematic presupposition than some properly revised version of teleological causality. This in itself does not imply the classical theistic explanation of creation, since it also yields a pantheistic explanation of the emergence of life and consciousness in our universe. (shrink)

Lewis’s Principal Principle says that one should usually align one’s credences with the known chances. In this paper I develop a version of the Principal Principle that deals well with some exceptional cases related to the distinction between metaphysical and epistemic modal­ity. I explain how this principle gives a unified account of the Sleeping Beauty problem and chance-­based principles of anthropic reasoning. In doing so, I defuse the Doomsday Argument that the end of the world is likely to be (...) nigh. GPI Working Paper No. 8-2021. (shrink)

According to the scenario of cosmological artificial selection and artificial cosmogenesis, our universe was created and possibly even fine-tuned by cosmic engineers in another universe. This approach shall be compared to other explanations, and some far-reaching problems of it shall be discussed.

The concept of contingency serves to bridge the doctrine of creation and natural science in Wolfhart Pannenberg's theology. My paper first analyzes the relation of creatio ex nihilo and creatio continua. Next I suggest three categories of contingency: global, local, and nomological. Under each category I assess Pannenberg's use of physics, cosmology, and philosophy of science. Although I agree with Pannenberg's emphasis on continuous creation and on the role of science in renewing the doctrine of creation, I argue for (...) a shift in the discussion from Pannenberg's topics to others, such as the anthropic principle, quantum physics, and thermodynamics. (shrink)

The Doomsday argument purports to show that the risk of the human species going extinct soon has been systematically underestimated. This argument has something in common with controversial forms of reasoning in other areas, including: game theoretic problems with imperfect recall, the methodology of cosmology, the epistemology of indexical belief, and the debate over so-called fine-tuning arguments for the design hypothesis. The common denominator is a certain premiss: the Self-Sampling Assumption. We present two strands of argument in favor of (...) this assumption. Through a series of thought experiments we then investigate some bizarre prima facie consequences – backward causation, psychic powers, and an apparent conflict with the Principal Principle. (shrink)

Paying strict attention to Brandon Carter's several published renditions of anthropic reasoning, we present a ``nutshell'' version of the Doomsday argument that is truer to Carter's principles than the standard balls-and-urns or otherwise ``naive Bayesian'' versions that proliferate in the literature. At modest cost in terms of complication, the argument avoids commitment to many of the half-truths that have inspired so many to rise up against other toy versions, never adopting posterior outside of the convex hull of one's prior (...) distribution over the ``true chance'' of Doom. The hyper-pessimistic position of the standard balls-and-urn presentation and the hyper-optimistic position of naive self-indicators are seen to arise from dubiously extreme prior distributions, leaving room for a more satisfying and plausible intermediate solution. (shrink)

Inspired by anthropic reasoning behind Doomsday arguments, Nick Bostrom's Simulation Argument says: people who think advanced civilisations would run many fully-conscious simulated minds should also think they're probably simulated minds themselves. However, Bostrom's conclusions can be resisted, especially by sympathisers with Doomsday or anthropic reasoning. This paper initially offers a posterior-probabilistic ‘Doomsday lottery’ argument against Bostrom's conclusions. Suggestions are then offered for deriving anti-simulation conclusions using weaker assumptions. Anti-simulation arguments herein use more robust reference classes than Bostrom's argument, (...) require no Principles of Indifference, abide better by the total evidence requirement, and yet use empirically plausible priors and likelihoods. However, while Doomsday arguments are probabilistically, epistemically and metaphysically stronger than the Simulation Argument, anthropic reasoning can refrain from embracing either. (shrink)