This book discusses the notion that quantum gravity may represent the "breakdown" of spacetime at extremely high energy scales. If spacetime does not exist at the fundamental level, then it has to be considered "emergent", in other words an effective structure, valid at low energy scales. The author develops a conception of emergence appropriate to effective theories in physics, and shows how it applies (or could apply) in various approaches to quantum gravity, including condensed matter approaches, discrete approaches, and loop (...) quantum gravity. (shrink)

Nagel’s official model of theory-reduction and the way it is represented in the literature are shown to be incompatible with the careful remarks on the notion of reduction Nagel gave while developing his model. Based on these remarks, an alternative model is outlined which does not face some of the problems the official model faces. Taking the context in which Nagel developed his model into account, it is shown that the way Nagel shaped his model and, thus, its well-known deficiencies, (...) are best conceived of as a mere by-product of his philosophical background. (shrink)

Assume that water reduces to H2O. If so water is identical to H2O. At the same time, if water reduces to H2O then H2O does not reduce to water–the reduction relation is asymmetric. This generates a puzzle–if water just is H2O it is hard to see how we can account for the asymmetry of the reduction relation. The paper proposes a solution to this puzzle. It is argued that the reduction predicate generates intensional contexts and that in order to account (...) for the asymmetry, we should develop conditions on the meanings of expressions that flank the reduction predicate in true reduction statements. Finally, it is argued that if we adopt this interpretation, we can illuminate the epistemological difference between reduced and reducing item commonly referred to in the literature. (shrink)

Philosophers look to the realization relation as a way to make sense of the possibility that special science kinds are physical, yet not reducible to kinds in physics. A realized property fails to reduce because it can be realized in multiple ways, thus blocking its identification with lower-level properties. One prominent analysis of realization, subset realization, distinguishes multiple realizers on the basis their “left-over powers,” that is, those that don’t contribute to the individuative powers of the realizer. However, I argue, (...) the subset analysis of realization fails to mark an important distinction between different ways that a property might be realized, and also makes questions about the reducibility of kinds—presumably an empirical issue—tractable from the armchair. I offer as an alternative mechanistic multiple realization, which avoids both these problems. (shrink)

This paper attempts a critical reappraisal of Nagel's (1961, 1970) model of reduction taking into account both traditional criticisms and recent defenses. This model treats reduction as a type of explanation in which a reduced theory is explained by a reducing theory after their relevant representational items have been suitably connected. In accordance with the deductive-nomological model, the explanation is supposed to consist of a logical deduction. Nagel was a pluralist about both the logical form of the connections between the (...) reduced and reducing theories (which could be conditionals or biconditionals) and their epistemological status (as analytic connections, conventions, or synthetic claims). This paper defends Nagel's pluralism on both counts and, in the process, argues that the multiple realizability objection to reductionism is misplaced. It also argues that the Nagel model correctly characterizes reduction as a type of explanation. However, it notes that logical deduction must be replaced by a broader class of inferential techniques that allow for different types of approximation. Whereas Nagel (1970), in contrast to his earlier position (1961), recognized the relevance of approximation, he did not realize its full import for the model. Throughout the paper two case studies are used to illustrate the arguments: the putative reduction of classical thermodynamics to the kinetic theory of matter and that of classical genetics to molecular biology. (shrink)

Philosophers have traditionally addressed the issue of scientific unification in terms of theoretical reduction. Reductive models, however, cannot explain the occurrence of unification in areas of science where successful reductions are hard to find. The goal of this essay is to analyse a concrete example of integration in biology—the developmental synthesis—and to generalize it into a model of scientific unification, according to which two fields are in the process of being unified when they become explanatorily relevant to each other. I (...) conclude by suggesting that this methodological conception of unity, which is independent of the debate on the metaphysical foundations of science, is closely connected to the notion of interdisciplinarity. 1 Introduction2 Some Troubles with Theory Reduction3 Interfield and Mechanistic Unification4 Foundations of the Developmental Synthesis5 Explanatory Relevance6 Concluding Remarks. (shrink)

Recent advancements in the brain sciences have enabled researchers to determine, with increasing accuracy, patterns and locations of neural activation associated with various psychological functions. These techniques have revived a longstanding debate regarding the relation between the mind and the brain: while many authors claim that neuroscientific data can be employed to advance theories of higher cognition, others defend the so-called ‘autonomy’ of psychology. Settling this significant issue requires understanding the nature of the bridge laws used at the psycho-neural interface. (...) While these laws have been the topic of extensive discussion, such debates have mostly focused on a particular type of link: reductive laws. Reductive laws are problematic: they face notorious philosophical objections and they are too scarce to substantiate current research at the intersection of psychology and neuroscience. The aim of this article is to provide a systematic analysis of a different kind of bridge laws—associative laws—which play a central, albeit overlooked role in scientific practice. (shrink)

Currently, there are almost as many conceptions of emergence as authors who address the issue. Most literature on the matter focuses either on discussing, evaluating and comparing particular contributions or accounts of emergence, or on assessing a particular case study. Our aim in this paper is rather different. We here set out to introduce a distinction that has not been sufficiently taken into account in previous discussions on this topic: the distinction between inter-domain emergence—a relation between items belonging to different (...) ontic domains—and intra-domain emergence—a relation between items belonging to a same ontic domain. Our final purpose is not to assume and defend a definite stance on emergence, but to stress the relevance of such distinction when attempting to argue for or against emergence, in the first place. We will also address the connections between emergence so distinguished and more general philosophical perspectives, suggesting where would reductionists and pluralists stand with respect to intra- and inter-domain emergence. (shrink)

Multiply realizable properties are those whose realizers are physically diverse. It is often argued that theories which contain them are ipso facto irreducible. These arguments assume that physical explanations are restricted to the most specific descriptions possible of physical entities. This assumption is descriptively false, and philosophically unmotivated. I argue that it is a holdover from the late positivist axiomatic view of theories. A semantic view of theories, by contrast, correctly allows scientific explanations to be couched in the most perspicuous, (...) powerful language available. On a semantic view, traditional notions of multiple realizability are thus very hard to motivate. At best, one must abandon either the idea that multiple realizability is an interesting scientific notion, or else admit that multiply realizable properties do not automatically block scientific reductions. (shrink)

In this paper I reply to Olimpia Lombardi’s comment on my recent book Reducing Chemistry to Physics: Limits, Models, Consequences.

Currently, there are almost as many conceptions of emergence as authors who address the issue. Most literature on the matter focuses either on discussing, evaluating and comparing particular contributions or accounts of emergence, or on assessing a particular case study. Our aim in this paper is rather different. We here set out to introduce a distinction that has not been sufficiently taken into account in previous discussions on this topic: the distinction between inter-domain emergence—a relation between items belonging to different (...) ontic domains—and intra-domain emergence—a relation between items belonging to a same ontic domain. Our final purpose is not to assume and defend a definite stance on emergence, but to stress the relevance of such distinction when attempting to argue for or against emergence, in the first place. We will also address the connections between emergence so distinguished and more general philosophical perspectives, suggesting where would reductionists and pluralists stand with respect to intra- and inter-domain emergence. (shrink)

The present paper surveys the three most prominent accounts in contemporary debates over how sound reduction should be executed. The classical Nagelian model of reduction derives the laws of the target-theory from the laws of the base theory plus some auxiliary premises (so-called bridge laws) connecting the entities of the target and the base theory. The functional model of reduction emphasizes the causal definitions of the target entities referring to their causal relations to base entities. The new-wave model of reduction (...) deduces not the original target theory but an analogous image of it, which remains inside the vocabulary of the base theory. One of the fundamental motivations of both the functional and the new-wave model is to show that bridge laws can be evaded. The present paper argues that bridge laws—in the original Nagelian sense—are inevitable, i.e. that none of these models can evade them. On the one hand, the functional model of reduction needs bridge laws, since its fundamental concept, functionalization, is an inter-theoretical process dealing with entities of two different theories. Theoretical entities of different theories (in a general heterogeneous case) do not have common causal relations, so the functionalization of an entity—without bridge laws—can only be executed in the framework of its own theory. On the other hand, the so-called images of the new-wave account cannot be constructed without the use of bridge laws. These connecting principles are needed to guide the process of deduction within the base theory; without them one would not be able to recognize if the deduced structure was an image of the target theory. (shrink)

Various scientific theories stand in a reductive relation to each other. In a recent article, we have argued that a generalized version of the Nagel-Schaffner model (GNS) is the right account of this relation. In this article, we present a Bayesian analysis of how GNS impacts on confirmation. We formalize the relation between the reducing and the reduced theory before and after the reduction using Bayesian networks, and thereby show that, post-reduction, the two theories are confirmatory of each other. We (...) then ask when a purported reduction should be accepted on epistemic grounds. To do so, we compare the prior and posterior probabilities of the conjunction of both theories before and after the reduction and ask how well each is confirmed by the available evidence. (shrink)

Philosophers of science since Nagel have been interested in the links between intertheoretic reduction and explanation, understanding and other forms of epistemic progress. Although intertheoretic reduction is widely agreed to occur in pure mathematics as well as empirical science, the relationship between reduction and explanation in the mathematical setting has rarely been investigated in a similarly serious way. This paper examines an important particular case: the reduction of arithmetic to set theory. I claim that the reduction is unexplanatory. In defense (...) of this claim, I offer evidence from mathematical practice, and I respond to contrary suggestions due to Steinhart, Maddy, Kitcher and Quine. I then show how, even if set-theoretic reductions are generally not explanatory, set theory can nevertheless serve as a legitimate foundation for mathematics. Finally, some implications of my thesis for philosophy of mathematics and philosophy of science are discussed. In particular, I suggest that some reductions in mathematics are probably explanatory, and I propose that differing standards of theory acceptance might account for the apparent lack of unexplanatory reductions in the empirical sciences. (shrink)

A longstanding criticism of Ernest Nagel's model of reduction is that it fails to take theory change into account. This criticism builds on the received view that Nagelian reductions are incompatible with theory change. This article challenges the received view by showing that Nagel's model can easily accommodate theory change. Indeed, Nagel's model is essentially static as it only gives unchanging formal and nonformal conditions for reduction; in contrast, theory change belongs to the dynamic history of science; as a result, (...) the application of Nagel's model to scientific knowledge from different historical periods yields a series of Nagelian reductions of different degrees of reductive success. This Nagelian treatment of theory change is illustrated by considering the enterprise of reducing thermodynamics to statistical mechanics in the late nineteenth century. It is also contended that, in handling theory change Nagel's model has greater merits than subsequent models (exemplified by Kenneth Schaffner's general reduction-replacement model). This article concludes by suggesting that Nagel's model of reduction deals with theory change exactly in the same way as logical empiricism does with historicism. (shrink)

This is one of two papers about emergence, reduction and supervenience. It expounds these notions and analyses the general relations between them. The companion paper analyses the situation in physics, especially limiting relations between physical theories. I shall take emergence as behaviour that is novel and robust relative to some comparison class. I shall take reduction as deduction using appropriate auxiliary definitions. And I shall take supervenience as a weakening of reduction, viz. to allow infinitely long definitions. The overall claim (...) of this paper will be that emergence is logically independent both of reduction and of supervenience. In particular, one can have emergence with reduction, as well as without it; and emergence without supervenience, as well as with it. Of the subsidiary claims, the four main ones are: : I defend the traditional Nagelian conception of reduction ; : I deny that the multiple realizability argument causes trouble for reductions, or ``reductionism'' ; : I stress the collapse of supervenience into deduction via Beth's theorem ; : I adapt some examples already in the literature to show supervenience without emergence and vice versa. (shrink)

Climate policy decisions are decisions under uncertainty and are, therefore, based on a range of future climate scenarios, describing possible consequences of alternative policies. Accordingly, the methodology for setting up such a scenario range becomes pivotal in climate policy advice. The preferred methodology of the Intergovernmental Panel on Climate Change will be characterised as ,,modal verificationism"; it suffers from severe shortcomings which disqualify it for scientific policy advice. Modal falsificationism, as a more sound alternative, would radically alter the way the (...) climate scenario range is set up. Climate science's inability to find robust upper bounds for future temperature rise in line with modal falsificationism does not disprove that methodology, rather, this very fact prescribes even more drastic efforts to curb CO2 emissions than currently proposed. (shrink)

What is the role of bridge laws in inter-theoretic relations? An assumption shared by many views about these relations is that bridge laws enable reductions. In this article, I acknowledge the naturalness of this assumption, but I question it by presenting a context within thermal physics (involving phase transitions) in which the bridge laws, puzzlingly, seem to contribute to blocking the reduction.

The current view of the relationship between areas of the mind-brain sciences is one where cross-disciplinary collaboration is required to advance claims about the mind-brain that stand on firm epistemic footing. My goal in this dissertation is to analyze what it means for information from different areas of science to fit together to produce strong epistemic claims by addressing how and to what extent claims about the mind-brain are corroborated in scientific practice. Philosophers of science have advanced various concepts of (...) the notion of fitting together information from different areas of science and its relation to scientific progress (e.g., Bickle, 1998, 2003, 2006; Darden and Maull, 1977; Mitchell, 2002, 2003; Mitchell and Dietrich, 2006; Nagel 1949, 1970, 1979; Piccinini and Craver, 2011; and Roskies, 2010). However, each concept of fitting together is vague and subject to multiple clarificatory questions. To get a handle on the notion of fitting together, I introduce the term ‘interdisciplinary corroboration’ as a placeholder for the various accounts of fitting together to facilitate my investigation of how claims about the mind-brain are corroborated in scientific practice. I argue review papers are a good place to begin analyzing interdisciplinary corroboration; accordingly, I conduct a two-part analysis of a review paper by Eichenbaum (2013) entitled ‘Memory on Time’. I use the lessons from my analysis to develop and advance a methodology for philosophers of science interested in knowledge production for evaluating review papers for corroboration in the mind-brain sciences. (shrink)

In this talk I present the main results from Anta (2021), namely, that the theoretical division between Boltzmannian and Gibbsian statistical mechanics should be understood as a separation in the epistemic capabilities of this physical discipline. In particular, while from the Boltzmannian framework one can generate powerful explanations of thermal processes by appealing to their microdynamics, from the Gibbsian framework one can predict observable values in a computationally effective way. Finally, I argue that this statistical mechanical schism contradicts the Hempelian (...) (1958) thesis that the predictive power of a scientific theory is directly proportional to its explanatory potential, and vice versa. (shrink)

Recent advancements in the brain sciences have enabled researchers to determine, with increasing accuracy, patterns and locations of neural activation associated with various psychological functions. These techniques have revived a longstanding debate regarding the relation between the mind and the brain: while many authors now claim that neuroscientific data can be used to advance our theories of higher cognition, others defend the so-called `autonomy' of psychology. Settling this significant question requires understanding the nature of the bridge laws used at the (...) psycho-neural interface. While these laws have been the topic of extensive discussion, such debates have mostly focused on a particular type of link: reductive laws. Reductive laws are problematic: they face notorious philosophical objections and they are too scarce to substantiate current research at the interface of psychology and neuroscience. The aim of this article is to provide a systematic analysis of a different kind of bridge laws--associative laws--which play a central, albeit often overlooked, role in scientific practice. (shrink)

Quantum gravity is understood as a theory that, in some sense, unifies general relativity (GR) and quantum theory, and is supposed to replace GR at extremely small distances (high-energies). It may be that quantum gravity represents the breakdown of spacetime geometry described by GR. The relationship between quantum gravity and spacetime has been deemed ``emergence'', and the aim of this thesis is to investigate and explicate this relation. After finding traditional philosophical accounts of emergence to be inappropriate, I develop a (...) new conception of emergence by considering physical case studies including condensed matter physics, hydrodynamics, critical phenomena and quantum field theory understood as effective field theory. This new conception of emergence is unconcerned with the ideas of reduction and derivation (i.e. it holds that we may have emergence with reduction or without it). Instead, a low-energy theory (or model) is understood as emergent from a high-energy theory if it is novel and autonomous compared to the high-energy theory, and the low-energy physics is dependent in a particular, minimal sense on the high-energy physics (this dependence is revealed by the techniques of effective field theory and the renormalisation group). While novelty is construed in a broad sense, the autonomy comes essentially from the underdetermination of the high-energy theory by the low-energy theory, which reflects the minimal way in which the emergent, low-energy theory depends on the high-energy one. It results from the scaling behaviour of the theories and the limiting relations between them, and is demonstrated by the renormalisation group and effective field theory techniques, the idea of universality, and the phenomenon of symmetry-breaking. These ideas are important in exploring the relationship between quantum gravity and GR, where GR is understood as an effective, low-energy theory of quantum gravity. Without experimental data or a theory of quantum gravity, we rely on principles and techniques from other areas of physics to guide the way. As well as considering the idea of emergence appropriate to treating GR as an effective field theory, I investigate the emergence of spacetime (and other aspects of GR) in several concrete approaches to quantum gravity, including examples of the condensed matter approaches, the ``discrete approaches'' (causal set theory, causal dynamical triangulations, quantum causal histories and quantum graphity) and loop quantum gravity. (shrink)

I examine the debate between reductive and non-reductive physicalists, and conclude that if we are to be physicalists, then we should be reductive physicalists. I assess how both reductionists and non-reductionists try to solve the mind-body problem and the problem of mental causation. I focus on the problem of mental causation as it is supposed to be faced by non-reductionism: the so-called overdetermination problem. I argue that the traditional articulation of that problem is significantly flawed, and I show how to (...) articulate it properly: what I call the ‘super-overdetermination problem’. In doing so, I demonstrate that the problem of mental causation faced by non-reductionism is in fact a special case of the mind-body problem, as faced by non-reductionism, and that the former can’t be solved independently of the latter. I then assess the prospects for a particular family of non-reductive views that I call immanentism, and show that they fail to solve the super-overdetermination problem. Finally, I put forward two arguments to support the conclusion that physicalism entails reductionism. Both arguments establish, via distinct reasoning, the proposition that mental property instances are identical to physical property instances; and then each argument employs the inference, which I also defend, that if mental instances are physical instances, then mental properties are physical properties; hence, reductionism follows. (shrink)