Dean Rickles

Where does the study of the flow of time belong: physics, the cognitive sciences, philosophy, or somewhere else? Physicists and philosophers have set themselves up into two camps: those who believe there is genuine flow or becoming in the world and those who believe there is just a block of events. What had not been considered is whether the subjective feeling of flow of time is the same the world over, whether it could be tampered with by brain injury, or whether it is present at all developmental stages. We lay out the problem, explain terms, and provide synopses of relevant ideas.

_Thinking about Science, Reflecting on Art: Bringing Aesthetics and Philosophy of Science togethe_r is the first book to systematically examine the relationship between the philosophy of science and aesthetics. With contributions from leading figures from both fields this edited collection engages with such questions as: Does representation function in the same way in science and in art? What important characteristic do scientific models share with literary fictions? What is the difference between interpretation in the sciences and in the arts? Can there be a science of aesthetics? In what ways can aesthetics and philosophy of science be integrated? Aiming to develop the interconnections between the philosophy of science and the philosophy of art more broadly and more deeply than ever before this volume not only explores scientific representation by comparison with fiction but extends the scope of interaction to include metaphysical and other questions around methodology in mainstream philosophy of science, including the aims of science, the characterisation of scientific understanding, and the nature of observation, as well as drawing detailed comparisons between specific examples in both art and the sciences.

What is spacetime? General relativity and quantum field theory answer this question in very different ways. This collection of essays by physicists and philosophers looks at the problem of uniting these two most fundamental theories of our world, focusing on the nature of space and time within this new quantum framework, and the kind of metaphysical picture suggested by recent developments in physics and mathematics. This is a book that will inspire further philosophical reflection on recent advances in modern physics.

This brief paper shows how an exact analogue of Einstein's original hole argument can be constructed in the loop representation of quantum gravity. The new argument is based on the embedding of spin-networks in a manifold and the action of the diffeomorphism constraint on them. The implications of this result are then discussed. I argue that the conclusions of many physicists working on loop quantum gravity---Rovelli and Smolin in particular---that the loop representation uniquely supports relationalism are unfounded.

In this paper I wish to make some headway on understanding what \emph{kind} of problem the ``problem of time'' is, and offer a possible resolution---or, rather, a new way of understanding an old resolution. The response I give is a variation on a theme of Rovelli's \emph{evolving constants of motion} strategy. I argue that by giving correlation strategies a \emph{structuralist} basis, a number of objections to the standard account can be blunted. Moreover, I show that the account I offer provides a suitable ontology for time in both classical and quantum canonical general relativity

I argue that, under the glitz, dual theories are examples of theoretically equivalent descriptions of the same underlying physical content: I distinguish them from cases of genuine underdetermination on the grounds that there is no real incompatibility involved between the descriptions. The incompatibility is at the level of unphysical structure. I argue that dual pairs are in fact very strongly analogous to gauge- related solutions even for dual pairs that look the most radically distinct, such as AdS/CFT.

Many of the advances in string theory have been generated by the discovery of new duality symmetries connecting what were once thought to be distinct theories, solu- tions, processes, backgrounds, and more. Indeed, duality has played an enormously important role in the creation and development of numerous theories in physics and numerous fields of mathematics. Dualities often lie at those fruitful intersections at which mathematics and physics are especially strongly intertwined. In this paper I describe some of these dualities and unpack some of their philosophical conse- quences, focusing primarily on string-theoretic dualities. I argue that dualities fall uncomfortably between symmetries and gauge redundancies, but that they differ in that they point to genuinely new deeper structures.

‘Quantum Gravity’ does not denote any existing theory: the field of quantum gravity is very much a ‘work in progress’. As you will see in this chapter, there are multiple lines of attack each with the same core goal: to find a theory that unifies, in some sense, general relativity (Einstein’s classical field theory of gravitation) and quantum field theory (the theoretical framework through which we understand the behaviour of particles in non-gravitational fields). Quantum field theory and general relativity seem to be like oil and water, they don’t like to mix—it is fair to say that combining them to produce a theory of quantum gravity constitutes the greatest unresolved puzzle in physics. Our goal in this chapter is to give the reader an impression of what the problem of quantum gravity is; why it is an important problem; the ways that have been suggested to resolve it; and what philosophical issues these approaches, and the problem itself, generate. This review is extremely selective, as it has to be to remain a manageable size: generally, rather than going into great detail in some area, we highlight the key features and the options, in the hope that readers may take up the problem for themselves—however, some of the basic formalism will be introduced so that the reader is able to enter the physics and (what little there is of) the philosophy of physics literature prepared. I have also supplied references for those cases where I have omitted some important facts. Hence, this chapter is intended primarily as a catalyst for future research projects by philosophers of physics, both budding and well-matured.

In this chapter we consider economic systems, and in particular financial systems, from the perspective of the physics of complex systems (i.e. statistical physics, the theory of critical phenomena, and their cognates). This field of research is known as econophysics—alternative names are ‘financial physics’ and ‘statistical phynance.’ This title was coined in 1995 by Eugene Stanley, and since then its researchers have attempted to forge it as an independent and important field, one that stands in opposition to standard (‘Neo-Classical’) economic theory. Econophysicists argue that the empirical data is best explained in terms flowing out of statistical physics, according to which the (stylized) facts of economics are best understood as emergent properties of a complex system. However, some economists argue that the methods used by econophysics are not sufficient to prove the existence of underlying complexity in economic systems. The complexity claim can nonetheless be defended as a good example of an inference to the best explanation rather than a definitive deduction.

In this chapter I consider what recent work on background independent physics can do for structuralism, and what structuralism can do for background independent physics. I focus on the problems of time and observables in gravitational physics. The ‘frozen’ character of the observables of general relativity is usually considered to constitute a serious problem for the theory. I argue that by invoking correlations between physical quantities we can provide a natural explanation of the appear- ance of time and change in timeless structures. I argue that this response can resolve a problem with Max Tegmark’s ‘extreme structuralist’ position. I then consider what bearing the mathematical representation used has on the debate over the nature of structure in discussions of structural realism. I argue that it has both the resources to ground the notion of structure in physics and to answer the ‘no relations without relata’ objection.

Given that worlds are defined compositionally as maximally spatiotemporally interrelated sums of possible objects, or as recombinations of actual states of affairs: what of empty worlds? It seems that such theories cannot admit such worlds, for nothing cannot come from the fusion or recombination of something. This is generally supposed to rule out metaphysical nihilism, the claim that there might have been nothing. In this brief note, I argue that the two positions can be made compatible by modifying the relationship between possibilities and possible worlds

In this paper I look at causality in the context of intervention research, and discuss some problems faced in the evaluation of causal hypotheses via interventions. I draw attention to a simple problem for evaluations that employ randomized controlled trials. The common alternative to randomized trials, the observational study, is shown to face problems of a similar nature. I then argue that these problems become especially acute in cases where the intervention is complex (i.e. that involves intervening in a complex system). Finally, I consider and reject a possible resolution of the problem involving the simulation of complex interventions. The conclusion I draw from this is that we need to radically reframe the way we think about causal inference in complex intervention research

Structural realism has rapidly gained in popularity in recent years, but it has splintered into many distinct denominations, often underpinned by diverse motivations. There is, no monolithic position known as ‘structural realism,’ but there is a general convergence on the idea that a central role is to be played by relational aspects over object-based aspects of ontology. What becomes of causality in a world without fundamental objects? In this book, the foremost authorities on structural realism attempt to answer this and related questions: ‘what is structure?’ and ‘what is an object?’ Also featured are the most recent advances in structural realism, including the intersection of mathematical structuralism and structural realism, and the latest treatments of laws and modality in the context of structural realism. The book will be of interest to philosophers of science, philosophers of physics, metaphysicians, and those interested in foundational aspects of science.