The present volume of Time and Science series is devoted to Physical Sciences and Cosmology. Today more than ever, the question 'is Time an ontological property, a necessary ingredient for the physical description of the world, or a purely epistemological element, relative to our situation in the world?' worry physicists and cosmologists alike. For many of them, Relativity (and particularly General Relativity), as well as its reconciliation with quantum mechanics in the elaboration of a quantum theory of gravitation, points to a negative answer to the first alternative, and leads them to deny the objective reality of time. For others, the answer is nuanced by the evidence of an emerging temporal property when one climbs the scales of the complexity of systems and/or the applicability of the statistical laws of thermodynamics. But for some, the illusion of the unreality of time comes from certain confusions that they denounce, and plead for the re-establishment of time at the heart of physical theories.

Contents:

• The Physics of 'Now' (James B Hartle)


• Discovering Physical Time within Human Time (Ronald P Gruber, Carlos Montemayor and Richard A Block)


• New (and Old) Work on the Fundamentality of Time (Dean Rickles and Jules Rankin)


• The Layers That Build Up the Notion of Time (Carlo Rovelli)


• Senses in Which Time Does and Does Not Exist (Julian Barbour)


• The Complex Timeless Emergence of Time in Quantum Gravity (Daniele Oriti)


• Time and Durations in Relativistic Physics (Marc Lachièze-Rey)


• Problem of Time: Lie Theory Suffices to Resolve It (Edward Anderson)


• Views, Variety, and Celestial Spheres (Lee Smolin)


• Scientific Cosmogony, the Time in Quantum Relativistic Physics (Gilles Cohen-Tannoudji and Jean-Pierre Gazeau)


• PT Symmetry (Carl M Bender)


• Experimental Evidence for Time Reversal Violation (David G Hitlin)


• Free Will and the Arrow of Time (Marina Cortês)

Readership: Researchers and people with academic or teaching professions in Physics (particularly General Relativity, Quantum Mechanics, Quantum Gravitation, Cosmology), or Philosophy of Science.

Key Features:

• Examines the fundamental question of how the concept of time fits into a theoretical description of the universe by psychologists to theoretical physicists and cosmologists. This has become a hotly-debated question, as theories of quantum gravitation point to timeless theories, consistent with the most popular interpretation of Einsteinian Relativity with its full determinism and block-universe. However, scientists including Lee Smolin, Dean Rickles and Jules Rankin, are convinced that we need time in the more fundamental physical theories, while others like Daniel Oriti, Gilles Cohen-Tannoudji and Jean-Pierre Gazeau explore new ways to give the concept a role in modern cosmology