What makes time special?

Description

As we navigate through life we instinctively model time as having a flowing present that divides a fixed past from open future. This model develops in childhood and is deeply saturated within our language, thought and behavior, affecting our conceptions of the universe, freedom and the self. Yet as central as it is to our lives, physics seems to have no room for this flowing present. What Makes Time Special? demonstrates this claim in detail and then turns to two novel positive tasks. First, by looking at the world "sideways" - in the spatial directions -- it shows that physics is not "spatializing time" as is commonly alleged. Even relativity theory makes significant distinctions between the spacelike and timelike directions, often with surprising consequences. Second, if the flowing present is an illusion, it is a deep one worthy of explanation. The author develops a picture whereby the temporal flow arises as an interaction effect between an observer and the physics of the world. Using insights from philosophy, cognitive science, biology, psychology and physics, the theory claims that the flowing present model of time is the natural reaction to the perceptual and evolutionary challenges thrown at us. Modeling time as flowing makes sense even if it misrepresents it. Content: Cover What Makes Time Special? Copyright Dedication Contents Acknowledgments List of Figures List of Boxes 1: The Problem of Time 1.1 Manifest Time 1.1.1 Now 1.1.2 Flow 1.1.3 Past/Future asymmetry 1.1.4 Is manifest time universal? 1.2 Physical Time 1.2.1 No manifest time 1.2.2 What makes time special? 1.3 The "Two Times" Problem 1.4 FromThere to Here 2: Lost Time: RelativityTheory 2.1 Classical Physics 2.1.1 Recovering space and time 2.1.2 Classical ideal clocks and manifest time 2.1.3 Trautman-Cartan theory 2.2 Relativity 2.3 Where's Time? 2.4 Minkowski Spacetime 2.5 L orentzian Time2.6 Outside Minkowski: Domes, Donuts, and Diamonds 2.7 Conclusion 3: Tearing Spacetime Asunder 3.1 Cauchy Time 3.2 "Unique" Time Functions 3.3 Time, Stuff, and Laws 3.4 Conclusion 4: Quantum Becoming? 4.1 Quantum Mechanics 4.2 Popper's Experimentis Crucis 4.2.1 Quantum preferred frames and time 4.2.2 Caveats and alternatives 4.2.3 The coordination problem 4.3 Quantum Becoming via Collapses? 4.4 Conclusion 5: Intimations of Quantum Gravitational Time 5.1 The Best of Times: "Asynchronous Becoming" in Causal Sets 5.1.1 The basic kinematics of CST 5.1.2 Taking growth seriously5.2 TheWorst of Times: Disappearing Time in Canonical Quantum Gravity 5.2.1 Semiclassical time 5.2.2 Justifying the approximations 5.3 Conclusion 6: The Differences Between Time and Space 6.1 The Project Reconceived 6.2 Time in Physics 6.2.1 The metric 6.2.2 Dimensionality 6.2.3 Mobility asymmetry 6.2.4 Direction of time 6.2.5 Natural kind asymmetry 6.3 The Fragmentation of Time 6.4 Conclusion 7: Laws, Systems, and Time 7.1 System Laws and Time 7.2 Time is the Great Informer 7.3 Binding Time 7.3.1 One-dimensionality 7.3.2 Closed timelike curves 7.3.3 The direction of time7.3.4 Natural kind asymmetry 7.4 Metaphysical Variations 7.5 Questions and Connections 7.6 onclusion 8: Looking at the World Sideways 8.1 Strength and Well-posed Cauchy Problems 8.2 The Worlds 8.3 Proposal 8.4 The Argument 8.5 Illustration 8.6 Is It Time? 8.7 Turning Pages in Non-temporal Directions 8.7.1 Pages of light 8.7.2 Pages of time 8.8 Conclusion 9: Do We Experience the Present? 9.1 Metaphysics of Time 9.2 The Problem of the Presence of Experience 9.3 The Temporal Knowledge Argument 9.4 From Metaphysics to Psychology: Perceived Synchrony 9.4.1 Temporal ventriloquism9.4.2 Temporal recalibration 9.4.3 Comments 9.5 Interlude: Measuring Subjective Simultaneity 9.6 Exploding the Now 9.7 Does Synchrony Pop Out? 9.8 Conclusion 10: Stuck in the Common Now 10.1 Disagreement and the Case of PH 10.2 Manufacturing the Now: Signals, Speed, and Stamps 10.2.1 Time stamps not needed 10.2.2 The common now 10.3 Wiggling in Time vsWiggling in Space 10.4 Conclusion 11: The Flow of Time: Stitching the World Together 11.1 Sharpening Focus 11.2 Meet IGUS 11.3 Getting IGUS Stuck in Time 11.4 Outfitting IGUS