Preface 2
CONTENT 3
Acknowledgements 6
CHAPTER 1: INTRODUCTION 7
Observation selection effects 7
A brief history of anthropic reasoning 10
Synopsis of this book 12
CHAPTER 2: FINE-TUNING ARGUMENTS IN COSMOLOGY 15
Does fine-tuning need explaining? 17
No “Inverse Gambler’s Fallacy” 19
Roger White and Phil Dowe’s analysis 21
Surprising vs. unsurprising improbable events 25
Observation selection effects 34
Conclusions 40
CHAPTER 3: Anthropic Principles, the motley family 43
The anthropic principle as expressing an observation selection effect 43
Anthropic hodgepodge 46
Freak observers and why earlier formulations are inadequate 50
The Self-Sampling Assumption 55
CHAPTER 4: thought experiments supporting the SELF-SAMPLING ASSUMPTION 57
The Dungeon 57
Two thought experiments by John Leslie 60
Incubator 61
The reference class problem 65
chapter 5: The Self-Sampling Assumption in science 69
SSA in cosmology 69
SSA in thermodynamics 71
SSA in evolutionary biology 73
SSA in traffic analysis 77
SSA in quantum physics 78
Summary of the case for SSA 81
CHAPTER 6: THE DOOMSDAY ARGUMENT 83
Introduction 83
Doomsday à la Gott 84
The incorrectness of Gott’s argument 86
Doomsday à la Leslie 88
The assumptions used in DA, and the Old evidence problem 90
Leslie on the problem with the reference class 97
Alternative conclusions of the Doomsday argument 100
CHAPTER 7: invalid objections against the DOOMSDAY ARGUMENT 102
Objection One (Korb and Oliver) 102
Objection Two (Korb and Oliver) 104
Objection Three (Korb and Oliver) 107
Objection Four (Korb and Oliver) 108
Objection Five (Korb and Oliver) 110
Couldn’t a Cro-Magnon man have used the Doomsday argument? (Various) 111
Aren’t we necessarily alive now? (Mark Greenberg) 111
Sliding reference of “soon” and “late”? (Mark Greenberg) 112
How could I have been a 16th century human? (Mark Greenberg) 112
Doesn’t your theory presuppose that the content of causally disconnected regions affects what happens here? (Ken Olum) 113
But we know so much more about ourselves than our birth ranks! (Various) 113
Safety in numbers? Why the Self-Indication Assumption should be rejected (several) 114
CHAPTER 8: OBSERVER-RELATIVE CHANCES IN ANTHROPIC REASONING? 118
Leslie’s argument, and why it fails 118
Observer-relative chances: another go 121
Discussion 123
Conclusion 126
Appendix 127
CHAPTER 9: PARADOXES OF THE SELF-SAMPLING ASSUMPTION 131
The Adam & Eve experiments 131
Analysis of Lazy Adam: predictions and counterfactuals 133
The UN++ gedanken: reasons, abilities, and decision theory 139
Quantum Joe: SSA and the Principal Principle 142
Conclusion 144
Appendix: The Meta-Newcomb problem 146
CHAPTER 10: Observation theory: A methodology for anthropic reasoning 147
Building blocks, theory constraints and desiderata 147
Outline of the solution 149
SSSA: Taking account of indexical information of observer-moments 149
Reassessing Incubator 152
How the reference class may be observer-moment relative 155
Formalizing the theory: the Observation Equation 158
A quantum generalization of OE 160
Non-triviality of the reference class: why must be rejected 161
Final thought on the reference class problem 167
Chapter 11: Observation selection theory applied to cosmological fine-tuning 170
Chapter 12: The Sleeping-Beauty problem: modelling imperfect recall 178
The Sleeping Beauty Problem 178
The case of no outsiders 179
The case with outsiders 180
Synthesis 181
General summary: How the theory measures up against desiderata 182
REFERENCES 184
Although I cannot name everybody who has helped me in some way with this manuscript, there are some persons who must be singled out for my special thanks: Paul Bartha, Darren Bradley, John Broome, Jeremy Butterfield, Erik Carlson, Douglas Chamberlain, Pierre Cruse, Wei Dai, J-P Delahaye, Jean-Michel Delhotel, Dennis Dieks, William Eckhardt, Ellery Eells, Adam Elga, Hal Finney, Paul Franceschi, Mark Greenberg, Robin Hanson, Daniel Hill, Christopher Hitchcock, Richard Jeffrey, Bill Jefferys, Vassiliki Kambourelli, Loren A. King, Kevin Korb, Eugene Kusmiak, Jacques Mallah, Neil Manson, Peter Milne, Bradley Monton, Floss Morgan, Jonathan Oliver, Ken Olum, Don N. Page, David Pearce, Elliott Sober, Richard Swinburne, Max Tegmark, Alexander Vilenkin, Saar Wilf, and Roger White. I am so grateful to all those friends, named and unnamed, without whose input this book could not have been written. (The faults that it contains, however, I was perfectly capable of producing all by myself!)
I want to especially thank John Leslie for his exceedingly helpful guidance, Colin Howson and Craig Callender for long assistance and advice, Nancy Cartwright for removing a seemingly insurmountable administrative obstacle, and Milan C. Ćirković for managing to keep up collaboration with me on a paper whilst bombs were falling all around him in Belgrade. Finally, I want to thank Robert Nozick for encouraging rapid publication.
I gratefully acknowledge a generous research grant from the John Templeton Foundation that helped fund large parts of the research. I’m thankful to Synthese, Mind, Analysis, and Erkenntnis for permitting texts to be republished here. The book is dedicated to my father – tack pappa!
