The Cosmic Microwave Background

Slobodan Perović is a professor of philosophy and history of science at the University of Belgrade. . He earned his Ph.D. at York University, Toronto, in 2005, and held teaching and research positions at Carleton University and the University of Pittsburgh, before returning to join the faculty in Belgrade in 2010. He is the principal convener of the 'Philosophy of Scientific Experimentation' conference series, and is author of From Data to Quanta: Niels Bohr's Vision of Physics (University of Chicago Press, 2021). Milan M. Ćirković is a senior researcher at the Astronomical Observatory of Belgrade. He also holds an adjunct position at the Future of Humanity Institute, University of Oxford. He has broad research interests in applying philosophical ideas to diverse areas including astrobiology and global catastrophic risks. His previous books include The Astrobiological Landscape: Philosophical Foundations of the Study of Cosmic Life (Cambridge University Press, 2012) and The Great Silence: Science and Philosophy of Fermi's Paradox (Oxford University Press, 2018).

'The Cosmic Microwave Background by Slobodan Perovic and Milan M. Cirkovic is a very welcome addition to the recent literature on the history and philosophy of experiment. The central focus is on the role that the discovery of the Cosmic Microwave Background (CMB) played in the establishment of the currently accepted 'hot big bang' theory of the origin of the universe. The authors also devote considerable discussion to the explanations of the CMB provided by alternative models of the origin, illustrating the complex relation between evidence and theory in cosmology. The discussion of the historical and philosophical issues is clear and well-written and will be understandable and valuable to those who are not expert in physics and cosmology. I strongly recommend it.' Allan Franklin, University of Colorado, Boulder

• Introduction; Part I. Physical Cosmology: A Brief Introduction: 1. Physical cosmology from Einstein to 1965; 2. The 'great controversy' (1948–65) and epistemological issues it raised; 3. Hot big bang and λCDM; Part II. Discovery of the CMB and Current Cosmological Orthodoxy: 4. Discovery of the CMB; 5. CMB phenomenology; 6. Standard 'textbook' history and its shortcomings; 7. Emergence of precision cosmology; Part III. What Constitutes an Unorthodoxy? Epistemological Framework of Cosmology: 8. Underdetermination of theories and models in cosmology; 9. Was the CMB a smoking gun?; 10. Classifying and analysing unorthodoxies; Part IV. Moderate Unorthodoxies: The CMB with the Big Bang: 11. Cold and tepid big bangs: population iii objects; 12. Models with unresolved sources; 13. Thermalization by grains, the first wave; 14. Primordial chaos; 15. Early intergalactic medium, massive population III objects and the large-numbers hypothesis; 16. Late thermalization of starlight; 17. 'An excess in moderation': high-baryon universe; Part V. Radical Unorthodoxies: The CMB Without the Big Bang: 18. Motivations: who's afraid of the big (bad) bang?; 19. Hoyle-narlikar theory and the changing masses origin of the CMB; 20. Revised steady state; 21. Closed steady-state models; 22. CMB in plasma cosmology; 23. CMB in non-expanding models; Part VI. Formation of the Orthodoxy and the Alternatives: Epistemological Lessons: 24. History and epistemology: the emergence of orthodoxy; 25. What about the alternatives?; 26. Pragmatic aspects of model-building and social epistemology of cosmology; 27. Large-scale numerical simulations in cosmology: beyond the theory-observations distinction?; Part VII. Other Philosophically Relevant Aspects of the CMB: 28. CMB and copernicanism: 'the axis of evil' and 'the fingers of god'; 29. The 'problem of other observers' and anthropic reasoning; 30. The nature of boundary conditions in cosmology, the CMB, and the 'laws of nature' debate; 31. CMB and the multiverse: limits of scientific realism?; Appendix 1: relativistic cosmological models; Appendix 2: dipole anisotropy; Notes; References; Index.