Recent developments in cosmology and particle physics, such as the string landscape picture, have led to the remarkable realization that our universe - rather than being unique - could be just one of many universes. The multiverse proposal helps to explain the origin of the universe and some of its observational features. Since the physical constants can be different in other universes, the fine-tunings which appear necessary for the emergence of life may also be explained. Nevertheless, many physicists remain uncomfortable with the multiverse proposal, since it is highly speculative and perhaps untestable. In this volume, a number of active and eminent researchers in the field - mainly cosmologists and particle physicists but also some philosophers - address these issues and describe recent developments. The articles represent the full spectrum of views, providing for the first time an overview of the subject. They are written at different academic levels, engaging lay-readers and researchers alike.
• Large number of distinguished contributors provide a broad range of perspectives, from enthusiastic support to deep skepticism • Contains contributions from cosmologists, astrophysicists, particle physicists and philosophers • Spans a range of levels, from articles that can be read by people with a scientific background to more advanced, technical articles
Part I. Overviews: 1. Introduction and overview Bernard Carr; 2. Living in the multiverse Steven Weinberg; 3. Enlightenment, knowledge, ignorance, temptation Frank Wilczek; Part II. Cosmology and Astrophysics: 4. Cosmology and the multiverse Martin J. Rees; 5. The anthropic principle revisited Bernard Carr; 6. Cosmology from the top down Stephen Hawking; 7. The multiverse hierarchy Max Tegmark; 8. The inflationary universe Andrei Linde; 9. A model of anthropic reasoning: the dark to ordinary matter ratio Frank Wilczek; 10. Anthropic predictions: the case of the cosmological constant Alexander Vilenkin; 11. The definition and classification of universes James D. Bjorken; 12. M/string theory and anthropic reasoning Renata Kallosh; 13. The anthropic principle, dark energy and the LHC Savas Dimopoulos and Scott Thomas; Part III. Particle Physics and Quantum Theory: 14. Quarks, electrons and atoms in closely related universes Craig J. Hogan; 15. The fine-tuning problems of particle physics and anthropic mechanisms John F. Donoghue; 16. The anthropic landscape of string theory Leonard Susskind; 17. Cosmology and the many worlds interpretation of quantum mechanics Viatcheslav Mukhanov; 18. Anthropic reasoning and quantum cosmology James B. Hartle; 19. Micro-anthropic principle for quantum theory Brandon Carter; Part IV. More General Philosophical Issues: 20. Scientific alternatives to the anthropic principle Lee Smolin; 21. Making predictions in a multiverse: conundrums, dangers, coincidences Anthony Aguirre; 22. Multiverses: description, uniqueness and testing George Ellis; 23. Predictions and tests of multiverse theories Don N. Page; 24. Observation selection theory and cosmological fine-tuning Nick Bostrom; 25. Are anthropic arguments, involving multiverses and beyond, legitimate? William R. Stoeger; 26. The multiverse hypothesis: a theistic perspective Robin Collins; 27. Living in a simulated universe John D. Barrow; 28. Universes galore: where will it all end? Paul Davies; Index.
'… probably the most comprehensive tome on the subject around at the moment and, like the others, I imagine it will have a long shelf-life … this well-constructed collection of writings is the best we can possibly hope for in the era of this new great debate.' Pedro Ferreira, Physics World
'This book really does lie at the frontier of cosmology, philosophy and possibly even theology. It is essential reading for anyone who wants to consider these ideas in depth.' Martin Redfern, Science, People and Politics
'Reading this book is a complex and rich experience. I find it useful as recommended reading as an introduction for undergraduate students.' Luca Valenziano, CERN Courier
'… an essential acquisition for those requiring an up to date account of the various physical proposals and their problems.' Science and Christian Belief