Craig Callender

In the science fiction novel Quarantine, Greg Egan imagines a universe where interactions with human observers collapse quantum wavefunctions. Aliens, unable to collapse wavefunctions, tire of being slaughtered by these collapses. In response they erect an impenetrable shield around the solar system, protecting the rest of the universe from human interference and locking humanity into a starless Bubble. When confronting scientific realism and the quantum, many philosophers try to do the theoretical counterpart of this fictional practical strategy. Quantum mechanics is beset with many hard-to-resolve interpretational challenges. Philosophers — appealing to decoherence and coarse-graining — try to put these in a bubble and hope that they can go about their philosophizing as before. My chapter aims to burst this Bubble.

Exponential discounted utility theory provides the normative standard for future discounting as it is employed throughout the social sciences. Tracing the justification for this standard through economics, philosophy and psychology, I’ll make what I believe is the best case one can for it, showing how a non-arbitrariness assumption and a dominance argument together imply that discounting ought to be exponential. Ultimately, however, I don’t find the case compelling, as I believe it is deeply flawed. Non-exponential temporal discounting is often rational–indeed, the paragon of rationality. If this is correct, it’s an important point when considering policy interventions. Instead of trying to “fix” non-exponetial discounting because it is irrational and associated with negative life outcomes, we might instead focus attention on why the conditions obtain that make such discounting rational.

Black hole thermodynamics is regarded as one of the deepest clues we have to a quantum theory of gravity. It motivates scores of proposals in the field, from the thought that the world is a hologram to calculations in string theory. The rationale for BHT playing this important role, and for much of BHT itself, originates in the analogy between black hole behavior and ordinary thermodynamic systems. Claiming the relationship is “more than a formal analogy,” black holes are said to be governed by deep thermodynamic principles: what causes your tea to come to room temperature is said additionally to cause the area of black holes to increase. Playing the role of philosophical gadfly, we pour a little cold water on the claim that BHT is more than a formal analogy. First, we show that BHT is often based on a kind of caricature of thermodynamics. Second, we point out an important ambiguity in what systems the analogy is supposed to govern, local or global ones. Finally, and perhaps worst, we point out that one of the primary motivations for the theory arises from a terribly controversial understanding of entropy. BHT may be a useful guide to future physics. Only time will tell. But the analogy is not nearly as good as is commonly supposed.

Phase transitions are an important instance of putatively emergent behavior. Unlike many things claimed emergent by philosophers, the alleged emergence of phase transitions stems from both philosophical and scientific arguments. Here we focus on the case for emergence built from physics, in particular, arguments based upon the infinite idealization invoked in the statistical mechanical treatment of phase transitions. After teasing apart several challenges, we defend the idea that phase transitions are best thought of as conceptually novel, but not ontologically or explanatorily irreducible to finite physics; indeed, by looking at ongoing work on “smooth phase transitions” we even suggest that they’re not even conceptually novel. In the case of renormalization group theory, consideration of infinite systems and their singular behavior provides a central theoretical tool, but this is compatible with an explanatory reduction. Phase transitions may be “emergent” in some sense of this protean term, but not in a sense that is incompatible with the reductionist project broadly construed.

Phase transitions are an important instance of putatively emergent behavior. Unlike many things claimed emergent by philosophers (e.g., tables and chairs), the alleged emergence of phase transitions stems from both philosophical and scientific arguments. Here we focus on the case for emergence built from physics, in particular, arguments based upon the infinite idealization invoked in the statistical mechanical treatment of phase transitions. After teasing apart several challenges, we defend the idea that phase transitions are best thought of as conceptually novel, but not ontologically or explanatorily irreducible to finite physics; indeed, by looking at ongoing work on “smooth phase transitions” we even suggest that they’re not even conceptually novel. In the case of renormalization group theory, consideration of infinite systems and their singular behavior provides a central theoretical tool, but this is compatible with an explanatory reduction. Phase transitions may be “emergent” in some sense of this protean term, but not in a sense that is incompatible with the reductionist project broadly construed.

An important feature of life is the temporal value asymmetry. Not to be confused with temporal discounting, the value asymmetry is the fact that we prefer future rather than past preferences be satisfied. Misfortunes are better in the past--where they are "over and done"--than in the future. Using recent work in empirical psychology and evolutionary theory, we develop a theory of the nature and causes of the temporal value asymmetry. The account we develop undercuts philosophy of time arguments such as that of Prior (1959), but more importantly, also begins a serious study of an interesting but understudied feature of our valuations and emotional attitudes. While in the spirit of certain past sketches about the possible origins of the temporal value asymmetry, our theory improves on them in many significant respects and suggests many clear avenues of future study. More generally, our hope is that work on the temporal value asymmetry will eventually attain the degree of rigor and explanatory power that the discounting asymmetry presently enjoys, for like this latter asymmetry, we believe the temporal value asymmetry has relevance to many practical issues in decision-making. Our paper can thus be seen as a call for a more unified methodological treatment of the two temporal asymmetries.

This is my commentary on Jonathan Schaffer's paper "Evidence for Fundamentality?”; both the paper and comments were presented at the Pacific APA, San Francisco, March 2001. Schaffer argues against the view that there is an ultimate fundamental level to the world. Seeing that quarks and leptons may have an infinite hierarchy of constituents, he claims, “empowers and dignifies the whole of nature” (15). Like Kant he holds that there are as good reasons for believing matter infinitely divisible as composed of fundamental simples. I’m afraid that Schaffer’s provocative arguments have not convinced me. In the paper, I criticize the idea that fundamentalism 'weakens' and 'denigrates' the whole of nature and try to show that an infinite hierarchy can not do the work Schaffer needs it to. I then argue that we should not in fact be agnostic between the two rival hypotheses.

Many believe that quantum mechanics makes the world hospitable to the tensed theory of time. Quantum mechanics is said to rescue the significance of the present moment, the mutability of the future and possibly even the whoosh of time’s flow. It allegedly does so in two different ways: by making a preferred foliation of spacetime into space and time scientifically respectable, and by wavefunction collapse injecting temporal ‘becoming’ into the world. The aim of this paper is to show that the reasoning underlying these claims is wishful thinking. Against the first claim I develop what I call the “coordination problem” for tensers. The upshot of this problem is that if tensers escape the threat of relativity, they do so only by embracing conflict with the branch of physics they believed saved them, quantum mechanics. I then step back from the fray and examine some methodological issues, concluding that scientific methodology will always be “against” tenses as they are currently conceived. The Appendix deals with the confused tangle of issues linking wavefunction collapse to an open future.

As the study of time has flourished in the physical and human sciences, the philosophy of time has come into its own as a lively and diverse area of academic research. Philosophers investigate not just the metaphysics of time, and our experience and representation of time, but the role of time in ethics and action, and philosophical issues in the sciences of time, especially with regard to quantum mechanics and relativity theory. This Handbook presents twenty-three specially written essays by leading figures in their fields: it is the first comprehensive collaborative study of the philosophy of time, and will set the agenda for future work.

As we navigate through life, we model time as flowing, the present as special, and the past as “dead.” This model of time—manifest time—develops in childhood and later thoroughly infiltrates our language, thought, and behavior. It is part of what makes a human life recognizably human. Yet if physics is correct, this model of the world is deeply mistaken. This book is about this conflict between manifest and physical time. The first half dives into the physics and philosophy to establish the conflict’s existence; but it also argues that the claim that physics “spatializes” time is overstated. Rather, even relativity theory makes time special in deep and significant ways. The second half turns to psychology, biology, and more, seeking to understand why creatures like us develop manifest time. The novel picture that results is that manifest time is a natural reaction to the many cognitive and evolutionary challenges that we face. For subjects embedded in our circumstances, it makes sense to develop—even if fundamentally wrong.

An important obstacle to lawhood in the special sciences is the worry that such laws would require metaphysically extravagant conspiracies among fundamental particles. How, short of conspiracy, is this possible? In this paper we'll review a number of strategies that allow for the projectibility of special science generalizations without positing outlandish conspiracies: non-Humean pluralism, classical MRL theories of laws, and Albert and Loewer's theory. After arguing that none of the above fully succeed, we consider the conspiracy problem through the lens of our preferred view of laws, an elaboration of the MRL view that we call the Better Best System (BBS) theory. BBS offers a picture on which, although all events supervene on a fundamental level, there is no one unique locus of projectibility; rather there are a large number of loci corresponding to the different areas (ecology, economics, solid-state chemistry, etc.) in which there are simple and strong generalizations to be made. While we expect that some amount of conspiracy-fear-inducing special science projectibility is inevitable given BBS, we'll argue that this is unobjectionable. It follows from BBS that the laws of any particular special or fundamental science amount to a proper subset of the laws. From this vantage point, the existence of projectible special science generalizations not guaranteed by the fundamental laws is not an occasion for conspiracy fantasies, but a predictable fact of life in a complex world

Perhaps the most significant contemporary theory of lawhood is the Best System (/MRL) view on which laws are true generalizations that best systematize knowledge. Our question in this paper will be how best to formulate a theory of this kind. We’ll argue that an acceptable MRL should (i) avoid inter-system comparisons of simplicity, strength, and balance, (ii) make lawhood epistemically accessible, and (iii) allow for laws in the special sciences. Attention to these problems will bring into focus a useful menu of novel MRL theories, some of which solve problems the original MRL theory could not. Hence we conceive of the paper as moving toward a better Best System theory of laws.

We propose that scientific representation is a special case of a more general notion of representation, and that the relatively well worked-out and plausible theories of the latter are directly applicable to thc scientific special case. Construing scientific representation in this way makes the so-called “problem of scientific representation” look much less interesting than it has seerned to many, and suggests that some of the (hotly contested) debates in the literature are concerned with non-issues.

Quantum mechanics, like any physical theory, comes equipped with many metaphysical assumptions and implications. The line between metaphysics and physics is often blurry, but as a rough guide, one can think of a theory’s metaphysics as those foundational assumptions made in its interpretation that are not usually directly tested in experiment. In classical mechanics some examples of possible metaphysical assumptions are the claims that forces are real, that inertial mass is primitive, and that space is substantival. The distinctive feature of these claims is that they are all rather far removed from ordinary tests of the theory. Newton defended all three of the above claims at one time or other, whereas Mach attacked each one; however, both scientists agreed on enough of the formalism and its connection to experiment to predict (e.g.) the same periods for given pendulums. What they disagreed about were the ingredients necessary to use classical mechanics to explain and understand the world.

No one conception of time emerges from a study of physics. As science changes—over time or through varying interpretations at a time—our conception of physical time changes. Each of these changes and resulting theories of time has been the subject of philosophical scrutiny, so there are many philosophical controversies internal to particular physical theories. For instance, the move to special relativity radically transformed our understanding of time, but it also gave rise to debates about the nature of simultaneity within the theory itself. Nevertheless, there are some philosophical puzzles that appear at every stage of the development of physics. Perhaps most generally, there is the perennial question, Is there a ‘gap’ between the conception of time as found in physics and the conception of time as found in philosophy?

In 1866 J.C. Maxwell thought he had discovered a Maxwellian demon—though not under that description, of course [1]. He thought that the temperature of a gas under gravity would vary inversely with the height of the column. From this he saw that it would then be possible to obtain energy for work from a cooling gas, a clear violation of Thompson’s statement of the second law of thermodynamics. This upsetting conclusion made him worry that “there remains as far as I can see a collision between Dynamics and thermodynamics.” Later, he derived the Maxwell-Boltzmann distribution law that made the temperature the same throughout the column. However, he continued to think about the relationship between dynamics and thermodynamics, and in 1867, he sent Tait a note with a puzzle for him to ponder. The puzzle was his famous “neat-fingered being” who could make a hot system hotter and a cold system colder without any work being done. Thompson in 1874 christened this being a “demon”; Maxwell unsuccessfully tried to rename it “valve.” However named, the demon’s point was to “show that the second law of thermodynamics has only a statistical validity.” Since that time a large physics literature has arisen that asks a question similar to that asked in theology, namely, does the devil exist? Beginning with Popper, philosophers examining the literature on Maxwell’s demon are typically surprised—even horrified [2,3,4,5,6,7]. As a philosopher speaking at a physics conference exactly 100 yrs after Popper’s birth, I want to explain why this is so. The organizers of this conference instructed me to offend everyone, believers and non-believers in demons. Thus my talk, apart from an agnostic middle section, contains a section offending those who believe they have exorcized the demon and a section offending those who summon demons. Throughout the central idea will be to clearly distinguish the various second laws and the various demons..

Philosophy of science appears caught in what Einstein (1933) called the ‘eternal antithesis between the two inseparable components of our knowledge – the empirical and the rational’ (p. 271). It wants to employ metaphysical speculation, but impressed with the methods of the subject it studies, it fears overreaching. Philosophy of science thus tries to walk a fine line between scientifically grounded metaphysics and its more speculative cousins. Here I try to draft some of the contour of this boundary.