Jenann Ismael

What is time? What does it mean for time to pass? Is it possible to travel in time? What is the difference between the past and future? Until the work of Newton, these questions were purely topics of philosophical speculation. Since then we've learned a great deal about time, and its study has moved from a subject of philosophical reflection to instead became part of the subject matter of physics. This Very Short Introduction introduces readers to the current physical understanding of the direction of time, from the Second Law of Thermodynamics to the emergence of complexity and life. Jenann Ismael charts the line of development in physical theory from Newton, via Einstein's Theory of Relativity, to the current day. Einstein's innovations led to a vision of time very different from the familiar time of everyday sense. In this new vision, time is one of the dimensions in which the universe is extended alongside the spatial dimensions. The universe appears as a static block of events, in which there is no more a difference between past and future than there is between east and west. Discussing the controversy and philosophical confusion which surrounded the reception of this new vision, Ismael also covers the contemporary mixture of statistical mechanics, cognitive science, and phenomenology that point the way to reconciling the familiar time of everyday sense with the vision of time presented in Einstein's theories."--Amazon.com.

This chapter argues that Humean analyses do not provide content‐preserving reductions and non‐trivial accounts of the reference. It introduces a distinction between structure in the realm of Being and structure in the representations of Being. The chapter argues that there are good reasons not to expect content‐preserving reductions of the modal to the non‐modal at the level of content, or useful mappings of content‐level structures into structures at the level of Being. In the rest of the chapter, the author deals with the relationship between content‐level structure and structure at the level of Being. The debate between the Humean and non‐Humean should be reconceived as a debate about whether non‐Humean facts play a substantive role in the story of how beliefs about laws and chances are formed and used.

Before the twentieth century, the Universe was usually imagined as a large spatially extended thing unfolding in time. The past was fixed and the future was open; unfolding was conceived as an asymmetric process of coming into being. Relativity introduced a new vision in which space and time are presented together as a single four-dimensional manifold of events. That, together with the fact that the fundamental laws of our classical theories are symmetric in time, made understanding why the past and future present themselves so differently in our experience one of the central challenges of physics. The last two centuries have seen a great deal of progress in understanding various of the so-called arrows of time: the thermodynamic arrow, the cosmological arrow, the arrow of knowledge or information. There remains an outstanding piece of this puzzle that has seen little progress, one that Roger Penrose described in his beautiful paper Singularities and Time-Asymmetry in 1979 as: “The arrow most difficult to comprehend … namely the feeling of relentless forward temporal progression, according to which potentialities seem to be transformed into actualities.”I will propose that the insight needed to resolve the problem involves taking into account that we are part of the universe and that any attempt to model it as a totality involves self-reference. I will argue specifically that self-reference, against the background of a thermodynamic gradient, creates an instability in an embedded agent’s ability to know the future or even treat it as a potential object of knowledge. That instability captures the sense in which the future remains for her perpetually open and the passage of time resolves openness into the fixity of fact.

Quantum mechanics seems to portray nature as nonseparable, in the sense that it allows spatiotemporally separated entities to have states that cannot be fully specified without reference to each other. This is often said to implicate some form of “holism.” We aim to clarify what this means, and why this seems plausible. Our core idea is that the best explanation for nonseparability is a “common ground” explanation, which casts nonseparable entities in a holistic light, as scattered reflections of a more unified underlying reality.

In a famous passage drawing implications from determinism, Laplace introduced the image an intelligence who knew the positions and momenta of all of the particles of which the universe is composed, and asserted that in a deterministic universe such an intelligence would be able to predict everything that happens over its entire history. It is not, however, difficult to establish the physical possibility of a counterpredictive device, i.e., a device designed to act counter to any revealed prediction of its behavior. What would happen if a Laplacean intelligence were put into communication with such a device and forced to reveal its prediction of what the device would do on some occasion? On the one hand, it seems that the Laplacean Intelligence should be able to predict the device's behavior. On the other hand, it seems like that device should be able to act counter to the prediction. An examination of the puzzle leads to clarification of what determinism does entail, with some insights about various other things along the way.

On April 1, 2016, at the Annual Meeting of the Pacific Division of the American Philosophical Association, a book symposium, organized by Alyssa Ney, was held in honor of David Albert’s After Physics. All participants agreed that it was a valuable and enlightening session. We have decided that it would be useful, for those who weren’t present, to make our remarks publicly available. Please bear in mind that what follows are remarks prepared for the session, and that on some points participants may have changed their minds in light of the ensuing discussion.

In 1687 Isaac Newton ushered in a new scientific era in which laws of nature could be used to predict the movements of matter with almost perfect precision. Newton's physics also posed a profound challenge to our self-understanding, however, for the very same laws that keep airplanes in the air and rivers flowing downhill tell us that it is in principle possible to predict what each of us will do every second of our entire lives, given the early conditions of the universe. Can it really be that even while you toss and turn late at night in the throes of an important decision and it seems like the scales of fate hang in the balance, that your decision is a foregone conclusion? Can it really be that everything you have done and everything you ever will do is determined by facts that were in place long before you were born? This problem is one of the staples of philosophical discussion. It is discussed by everyone from freshman in their first philosophy class, to theoretical physicists in bars after conferences. And yet there is no topic that remains more unsettling, and less well understood. If you want to get behind the façade, past the bare statement of determinism, and really try to understand what physics is telling us in its own terms, read this book. The problem of free will raises all kinds of questions. What does it mean to make a decision, and what does it mean to say that our actions are determined? What are laws of nature? What are causes? What sorts of things are we, when viewed through the lenses of physics, and how do we fit into the natural order? Ismael provides a deeply informed account of what physics tells us about ourselves. The result is a vision that is abstract, alien, illuminating, and-Ismael argues-affirmative of most of what we all believe about our own freedom. Written in a jargon-free style, How Physics Makes Us Free provides an accessible and innovative take on a central question of human existence.

The intuitive difference between a system that choreographs the motion of its parts in the service of goals of its own formulation and a system composed of a collection of parts doing their own thing without coordination has been shaken by now familiar examples of self-organization. There is a broad and growing presumption in parts of philosophy and across the sciences that the appearance of centralized information-processing and control in the service of system-wide goals is mere appearance, i.e., an explanatory heuristic we have evolved to predict behavior, but one that will eventually get swept away in the advancing tide of self-organization. I argue that there is a distinction of central importance here, and that no adequate science of complex systems can dispense with it

The role of probability is one of the most contested issues in the interpretation of contemporary physics. In this paper, I’ll be reevaluating some widely held assumptions about where and how probabilities arise. Larry Sklar voices the conventional wisdom about probability in classical physics in a piece in the Stanford Online Encyclopedia of Philosophy, when he writes that “Statistical mechanics was the first foundational physical theory in which probabilistic concepts and probabilistic explanation played a fundamental role.” And the conventional wisdom about quantum probabilities is that they are basic, not reducible to the types of probabilities we see in statistical mechanics. In the first section of this paper, I’ll argue that in fact classical physics was steeped in probability long before statistical mechanics came on the scene, specifically, that an objective measure over phase space is an indispensable component of any informative physical theory. In the next section, I’ll argue that this objective measure is the fundamental form of physical probability and that quantum probabilities can be defined in terms of it. In the last, I’ll raise some questions about the metaphysical status of the fundamental measure

I propose, in the context of Everett interpretations of quantum mechanics, a way of understanding how there can be genuine uncertainty about the future notwithstanding that the universe is governed by known, deterministic dynamical laws, and notwithstanding that there is no ignorance about initial conditions, nor anything in the universe whose evolution is not itself governed by the known dynamical laws. The proposal allows us to draw some lessons about the relationship between chance and determinism, and to dispel one source of the tendency among Everettians to introduce consciousness as a primitive element into physical description.

Philosophers of mind tend to take it for granted that causal relations are part of the mind-independent, objective fabric of the physical world. In fact, their status has been hotly contested since Russell famously observed that the closest thing to causal relations in physics are timesymmetric dynamical laws relating global time slices of world-history. 1 These bear a distant relationship to the local, asymmetric relations that form the core of the folk notion of cause. Nancy Cartwright, in an influential response, agreed about the absence of causal relations from physics, but argued that Russell’s position was not viable because agents choosing among potential actions need specifically causal information to distinguish effective from ineffective strategies for bringing about ends. 2 Causal beliefs play an ineliminable role in practical deliberation In recent years, there has been a great deal of progress in understanding the relationship between causal concepts and the dynamical laws that appear in advanced physics, together with a proliferation of new tools for representing and discovering causal structure

Human beings think of themselves in terms of a privileged non-descriptive designator — a mental “I”. Such thoughts are called “de se” thoughts. The mind/body problem is the problem of deciding what kind of thing I am, and it can be regarded as arising from the fact that we think of ourselves non-descriptively. Why do we think of ourselves in this way? We investigate the functional role of “I” (and also “here” and “now”) in cognition, arguing that the use of such non-descriptive “reflexive” designators is essential for making sophisticated cognition work in a general-purpose cognitive agent. If we were to build a robot capable of similar cognitive tasks as humans, it would have to be equipped with such designators. Once we understand the functional role of reflexive designators in cognition, we will see that to make cognition work properly, an agent must use a de se designator in specific ways in its reasoning. Rather simple arguments based upon how “I” works in reasoning lead to the conclusion that it cannot designate the body or part of the body. If it designates anything, it must be something non-physical. However, for the purpose of making the reasoning work correctly, it makes no difference whether “I” actually designates anything. If we were to build a robot that more or less duplicated human cognition, we would not have to equip it with anything for “I” to designate, and general physicalist inclinations suggest that there would be nothing for “I” to designate in the robot. In particular, it cannot designate the physical contraption. So the robot would believe “I exist”, but it would be wrong. Why should we think we are any different?

Is there more that one "Curie's principle"? How far are different formulations legitimate? What are the aspects that make it so scientifically fruitful, independently of how it is formulated? The paper is devoted to exploring these questions. We start with illustrating Curie's original 1894 article and his focus. Then, we consider the way that the discussion of the principle took shape from early commentators to its modern form. We say why we think that the modern focus on the inter-state version of the principle loses sight of some of the most interesting significant applications of the principle. Finally, we address criticism of the principle put forward by Norton and purported counterexamples due to Roberts.

For most of the major philosophers of the seventeenth and eighteenth centuries, human cognition was understood as involving the mind’s reflexive grasp of its own contents. But other important figures have described the very idea of a reflexive thought as incoherent. Ryle notably likened the idea of a reflexive thought to an arm that grasps itself. Recent work in philosophy, psychology, and the cognitive sciences has greatly clarified the special epistemic and semantic properties of reflexive thought. This article is an attempt to give an explicit characterization of the structure of reflexive thoughts that explains those properties and avoids the complaints of its critics

The chance of a physical event is the objective, single-case probability that it will occur. In probabilistic physical theories like quantum mechanics, the chances of physical events play the formal role that the values of physical quantities play in classical physics, and there is a temptation to regard them on the model of the latter as describing intrinsic properties of the systems to which they are assigned. I argue that this understanding of chances in quantum mechanics, despite being a part of the orthodox interpretation of the theory and the most prevalent view in the physical community, is incompatible with a very wide range of metaphysical views about the nature of chance. The options that remain are unlikely to be attractive to scientists and scientifically minded philosophers.

The most potentially powerful objection to the possibility oftime travel stems from the fact that it can, under the right conditions, give rise to closedcausal loops, and closed causal loops can be turned into self-defeating causal chains;folks killing their infant selves, setting out to destroy the world before they were born,and the like. It used to be thought that such chains present paradoxes; the receivedwisdom nowadays is that they give rise to physical anomalies in the form of inexplicably correlated events. I argue against the received wisdom. I can find nothing in them that argues against the possibility (even, the probability) of time travel.

Quantum mechanics seems to portray nature as nonseparable, in the sense that it allows spatiotemporally separated entities to have states that cannot be fully specified without reference to each other. This is often said to implicate some form of “holism.” We aim to clarify what this means, and why this seems plausible. Our core idea is that the best explanation for nonseparability is a “common ground” explanation, which casts nonseparable entities in a holistic light, as scattered reflections of a more unified underlying reality.

In the general project of trying to reconcile the subjective view of the world (how things seem from the perspective of the embedded agent) with the objective view (the view of the world from the outside, as represented, for example, in our best physics), analytic philosophy, especially in recent years, has been almost solely focused on sensory phenomenology.1 There are two very salient features of the subjective view that haven’t been explored even on the descriptive side but that present prima facie problems at least as great as sensory phenomenology. One is agential phenomenology (the experience of ourselves as agents in the world), and the other is temporal phenomenology. 2 The problems presented by these cases are very different. I want to focus on temporal phenomenology, by which I mean the felt character of a life lived in time. And my goal here is mostly descriptive; I’ll be exploring the question of what it is like to be the kind of being that has a history, that experiences that history in stages, and that keeps a running record of that history as it unfolds. 3 My suggestion is going to be that there is a special phenomenology, not supervenient on the sensory phenomenology, that arises only in the representational setting created by autobiographical memory and that is central to the felt character of a life lived in time. 4 (by autobiographical memory here, I mean not simply what is sometimes referred to as episodic memory - mental images of past experiences - I mean an explicit, account of one’s own history, rendered in explicitly first-personal form. (the difference here is the difference between a perspectival representation centered on the self of the sort that visual experience gives us and an explicit representation of self, of the sort you have, for example when you translate visual experience into a first personal belief like “I am such and such a place, seeing such and such”)..