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This chapter discusses the idea that the treatment of time in present-day physical theories, general relativity and quantum theory, might be an approximation to a very different treatment in the as yet unknown quantum theory of gravity. It considers the general idea that one theory could be emergent from another, emergence being a relation analogous to, but weaker than, intertheoretic reduction. It also gives a broad description of the search for a quantum theory of gravity and some of its interpretative problems. Thereafter, the discussion focuses on the emergence of time in two specific quantum gravity programmes: quantum geometrodynamics and the Euclidean programme. It also addresses the so-called ‘problem of time’. It is really a cluster of problems; technical and conceptual, arising from how time is treated very differently in general relativity and quantum theory.

This chapter presents the quantization of canonical gravity in the metric formulation. The central equations are the Wheeler-DeWitt equation and the quantum diffeomorphism constraints, whose general properties are discussed at length. Special attention is focused on conceptual problems such as the problems of time and the inner product. The chapter includes general remarks on the functional Schr\"odinger picture, the connection with path integrals, and the extension of the formalism to quantum supergravity. A detailed section is devoted to the semiclassical approximation. Starting from quantum mechanical analogies, an approximate functional Schr\"odinger equation as well as quantum gravitational corrections are derived and discussed. Possible observational tests are pointed out.

This chapter considers in great detail the quantization of canonical gravity in the metric formulation. The central equations are the Wheeler–DeWitt equation and the quantum diffeomorphism constraints, whose general properties are discussed. Special attention is focused on conceptual problems such as the problems of time and the inner product. The chapter includes general remarks on the functional Schrödinger picture, the connection with path integrals, and the extension of the formalism to quantum supergravity. A detailed section is devoted to the semiclassical approximation. Starting from quantum mechanical analogies, an approximate functional Schrödinger equation as well as quantum gravitational corrections are derived and discussed.

Using the Doomsday Clock as an organizing symbol, the introduction makes the case for time’s relevance to a range of global political phenomena, clears important conceptual ground, and sets the stage for the theory and analyses to follow. It notes a number of empirical and disciplinary areas where time and temporal assumptions play important roles but argues that International Relations (IR) mostly fails to take time seriously as an object of analysis in its own right. It then sketches two dominant and seemingly contradictory cultures of time operating across politics and IR: Western standard time, or the time reckoned by reliable clocks and calendars; and the problem of Time—a much more venerable and vindictive image of time as antagonistic to human and social life, sometimes couched in fluvial metaphors. The problem of Time tradition sets up politics in practice and in theory as efforts to tame Time with sound knowledge and effective action, often linked to Western standard time symbols. Before summarizing the rest of the book, the introduction argues that the prevalence of these two contradictory time cultures in IR opens up important questions about the field’s relationship to time and its means of engaging global politics.

Chapter two makes the case for timing theory’s value. Timing offers a simple but powerful gestalt shift, from taking “times” as existential givens or temporalities as subjective and subordinate constructs to a rigorous framework for tracing how practices and symbolic language interact to produce all the times of our lives—from our innermost experiences to the rhythms of the universe. These only become “real” and “natural” if they work for us almost by second nature. Timing theory also resolves several thorny problems with our grasp of time. Within IR, timing theory offers superior explanatory power while accommodating and often clarifying the way that other time studies approach their subject matter. It further stands apart in its ability to integrate IR’s two dominant cultures of time—Western standard time and the problem of Time. Finally, it exposes basic issues in IR as matters of timing, from concerns with change and surprise, to scholarly practices and knowledge development, to central disciplinary discussions like the “neo-neo debate.”

The book’s conclusion takes stock of insights developed throughout and highlights some of their wider implications. After summarizing narrative timing theory’s contributions to IR and our understanding of time, it proposes that taking timing seriously entails rethinking several aspects of what it means to do IR. Timing theory suggests that IR’s intellectual and academic hierarchies require revision and perhaps outright inversion. It also shows how, in re-timing IR, scholars can also re-claim their field from arbitrary and largely impertinent scientific standards ill-suited to the level of difficulty at which IR scholarship operates. Timing theory also bears on recent efforts to cultivate a more reflexive brand of scholarship, warning against the tendency to reify any methodological, theoretical, or disciplinary doxa when studying the temporal domain of global politics.

In early childhood we come to model the world as having a special present that carves the world up into a past, present, and future. We regard the past as fixed and the future open, and we feel that this structure updates itself, or flows. The core features of this conception of time—manifest time—appear to be virtually universal, and they pervade our language, thought, and behavior. Yet manifest time seems to conflict with time as understood by physics. This conflict worried Albert Einstein, but the philosopher Rudolph Carnap pointed toward a way forward.

This chapter discusses several topics in which loop quantum gravity techniques have been applied. These include black hole entropy in the context of black hole thermodynamics and how loop quantum gravity accounts for the entropy; the master constraint technique and the closely related uniform discretizations as a means of dealing with some of the problems of the Hamiltonian constraint; the spin foam techniques to treat the covariant quantization of gravity via path integral techniques; the possibility that observational effects could arise in the dispersion of the light that arrives from gamma ray bursts; possible limitations in the measurement of times and distances; and the problem of time in quantum gravity and recent proposals to deal with it.

This chapter explains in detail the current Hamiltonian formulation of SD, and the concept of Linking Theory of which (GR) and SD are two complementary gauge-fixings. The physical degrees of freedom of SD are identified, the simple way in which it solves the problem of time and the problem of observables in quantum gravity are explained, and the solution to the problem of constructing a spacetime slab from a solution of SD (and the related definition of physical rods and clocks) is described. Furthermore, the canonical way of coupling matter to SD is introduced, together with the operational definition of four-dimensional line element as an effective background for matter fields. The chapter concludes with two ‘structural’ results obtained in the attempt of finding a construction principle for SD: the concept of ‘symmetry doubling’, related to the BRST formulation of the theory, and the idea of ‘conformogeometrodynamics regained’, that is, to derive the theory as the unique one in the extended phase space of GR that realizes the symmetry doubling idea.

Some models of time do not match the human experience of time ‘flowing’ or passing. This chapter touches upon those models that suggest that this experience is an illusion. The Block Universe model is a contextually incomplete geometric model of spacetime that explicitly fails to describe our feeling of the ‘now’ or the moment of the present. The chapter discusses this and the phenomenon of persistence and transtemporality, that conspire to give us the impression that things exist or endure in time. The chapter discusses the extreme form of this, the so-called problem of time in quantum cosmology, which suggests that the wave-function of the universe is changeless and that time does not exist on the cosmological level.

This chapter reviews the parametrization of absolute time and develop the concept of temporal reparametrizations, or changes in our clocks. Using the action integral and Dirac’s constraint mechanics, the chapter discusses the mathematics of temporal reparametrization and reparametrization form invariance. This latter is related to general covariance in general relativity. Working in an extended phase space that now includes time and its associated ‘momentum’, the chapter derives the result that the extended Hamiltonian is zero on the surface of constraints, that is, over the true or classical trajectory. The implications of this for quantum cosmology and the ‘problem of time’ discussed in Chapter 8 are examined and analysed in terms of contextual completeness.