GOD, CHANCE AND PURPOSE Scientific accounts of existence give chance a central role. At the smallest level, quantum theory involves uncertainty, and evolution is driven by chance and necessity. These ideas do not fit easily with theology, in which chance has been seen as the enemy of purpose. One option is to argue, as proponents of Intelligent Design do, that chance is not real and can be replaced by the work of a Designer. Others adhere to a deterministic theology in which God is in total control. Neither of these views, it is argued, does justice to the complexity of nature or the greatness of God. The thesis of this book is that chance is neither unreal nor non-existent but an integral part of God s creation. This view is expounded, illustrated and defended by drawing on the resources of probability theory and numerous examples from the natural and social worlds. is Emeritus Professor of Statistics at the London School of Economics and Political Science. His numerous publications include Measuring Intelligence: Facts and Fallacies (2004).
GOD, CHANCE AND PURPOSE Can God Have It Both Ways? DAVID J. BARTHOLOMEW
cambridge university press Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo, Delhi, Mexico City Cambridge University Press The Edinburgh Building, Cambridge cb2 8ru, UK Published in the United States of America by Cambridge University Press, New York Information on this title: /9780521707084 2008 This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 2008 A catalogue record for this publication is available from the British Library isbn 978-0-521-88085-5 Hardback isbn 978-0-521-70708-4 Paperback Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. Information regarding prices, travel timetables, and other factual information given in this work is correct at the time of first printing but Cambridge University Press does not guarantee the accuracy of such information thereafter.
Contents List of figures Preface page vii ix 1 What is the problem? 1 2 What is chance? 16 3 Order out of chaos 28 4 Chaos out of order 55 5 What is probability? 67 6 What can very small probabilities tell us? 77 7 Can Intelligent Design be established scientifically? 97 8 Statistical laws 116 9 God s action in the quantum world 136 10 The human use of chance 156 11 God s chance 173 12 The challenge to chance 196 v
vi Contents 13 Choice and chance 211 14 God and risk 223 References 243 Further reading 248 Index 250
Figures 3.1 The form of the exponential frequency distribution page 35 3.2 The form of the normal frequency distribution 37 8.1 The frequency distribution of the two outcomes in a single toss of a fair coin 122 8.2 The frequency distribution of run length in successive tosses of a fair coin 123 8.3 The binomial distribution of the number of heads in four tosses of a fair coin 124 vii
Preface Chance has become an integral part of contemporary science but, for the most part, is still not at home in theology. Theology speaks of a purposeful God while chance, by very definition, seems to signify a total lack of purpose. To suggest the very opposite that chance lies within the purposes of God may seem perverse, if not foolhardy, and yet that is precisely what is argued for in this book. One might have expected that the slow seepage of evolutionary theory or quantum theory into the public consciousness would at least have softened the hard edges of the confrontation. But to change the metaphor the Intelligent Design debate has fanned the dying embers into flames. Atheistic evolution is now set in stark opposition to the theistic design which Intelligent Design sees as responsible for the wonder of the universe. This, therefore, is an opportune moment to argue again for the positive benefits which flow to theology from seeing chance as an intended part of the creation. As is so often the case when matters are hotly disputed, the stark conflict between opposites begins to dissolve when we examine them carefully. Much depends on the level at which we choose to observe the world. Many of the regularities of nature are built on randomness and much of the seeming randomness around us is like a shower of sparks thrown off by ix
x Preface the lawfulness of processes on a larger scale. Self-organisation in apparently disorganised systems occurs on such a scale that one suspects it does not emerge by accident. It is just possible that primeval chaos was the precondition of a lawful world. This is an exciting question which is probed from several angles in this book. I make no pretence that this is an easy book, even for those who are familiar with, if not expert in, the technical material which lies behind it. Many of the big recurring questions with which the theological giants have wrestled over the centuries reappear in these pages. The theology of chance is no magic solvent to dissolve the problems of yesteryear. What I do claim is that there is a great deal of misunderstanding which can be dispelled by rigorously subjecting widely accepted arguments to the critical eyes of someone trained in the statistical sciences. These are not, in themselves, intrinsically difficult so much as unfamiliar but the reader must expect to read slowly and to go over the ground several times, perhaps. I hope that the use of familiar, even homely, examples in place of mathematics will help. As an additional help, each chapter begins with a brief summary of its argument. I suspect that chapter 7, refuting Dembski s claim to have produced a method for eliminating chance as an explanation, will be particularly challenging. It is, perhaps, also the most important chapter. Although I have reduced the technical matter to a minimum, it is essential to engage with Dembski on his own ground and in his own language. He has not spared his lay readers and I have, to some extent, followed his example. There is, in fact, almost no technical discussion in the book which requires formulae for its expression and very little use is made of symbols. This does not really make things any easier because the economy and clarity of a mathematical argument makes it, typically, briefer and more precise than the equivalent
Preface verbal version. Its absence however, does make the text more reader-friendly and that counts for much. This observation should not lull one into thinking that probabilities, for example, can be plucked from thin air by some sort of innate intuition. Probability theory provides the backbone of reasoning about chance. Although it is not necessary to understand the theory to grasp the message of the book, it is important to follow the gist of the argument, and in particular, to be aware of the pitfalls which await the unwary. For this reason, some chapters represent a marking time in the progress of the main argument as I secure the foundations, albeit informally. This is not the first time that I have ventured into this field. My God of Chance appeared in 1984. It is now out of print and seriously out-of-date although it is still available and may be downloaded free of charge at www.godofchance.com. Its primary aim, appropriate at the time, was to counter the implication of books such as Monod s Chance and Necessity that science had finally banished belief in God to the obscurantist backwoods. At that time I was not as well informed as I ought to have been about the late Arthur Peacocke s thinking in the same direction. The aim here is more ambitious, namely to give chance its rightful place in serious theology. My Uncertain Belief, first published in 1996, discussed reasoning about theological matters in an uncertain world. The uncertainty there was in our heads rather than in the world. For the rest, articles, lectures and chapters in books have provided the opportunity to develop many of the strands of thought which have come together in this book. Chapter 14 is a shortened and updated version of the Gowland lecture which I gave to the Christ and the Cosmos Initiative at Westminster College, Oxford in 1999. It represents a first attempt to draw out, on a small front, the kind of theological thinking that is becoming imperative. xi
xii Preface The footnotes serve the usual purpose of leading the reader into interesting and relevant byways. However, the reader with access to the Internet can track down a wealth of additional information by using a search engine such as Google. Occasionally web addresses are given here but the use of a search engine is so easy that they are almost superfluous. As a solitary thinker I may not acknowledge, as readily as I should, the debt I owe to others. Most of those from whom I have learnt much will recognise their contributions in these pages. I now find it impossible to identify and properly apportion credit where it is due. However, the Science and Religion community in the United Kingdom and internationally is a constant reminder of the interdependence of all thinking in this field. In a book of this kind a disclaimer is essential. Anyone attempting to span so many disciplines must, inevitably, echo St Paul, who asked, in a different context: who is sufficient for these things? (2 Cor. 2.15) The short answer, of course, is: no one. But if the apologetic task is not to go by default someone must take the risk. My only claim is that I am a statistical scientist whose work has taken him into many other fields. As one of the most famous of my colleagues (the late John Tukey) once said, the best thing about being a statistician is that you get to play in everyone else s back yard. It is becoming increasingly difficult to know how to thank my wife adequately for her continual and very practical support. Indeed, in these gender-sensitive days, it is hard to know whether these things should be mentioned in public at all! Whatever the proprieties, I cannot conclude without remarking that Proverbs 31.10 31 gets it about right.